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Doxepin (Systemic)


General


Pronunciation

(DOKS e pin)


Brand Names: U.S.

  • Silenor

Indications


Use: Labeled Indications

Depression and/or anxiety: Treatment of psychoneurotic patients with depression and/or anxiety; depression and/or anxiety associated with alcoholism; depression and/or anxiety associated with organic disease; psychotic depressive disorders with associated anxiety, including involutional depression and manic-depressive disorders.

Insomnia (Silenor only): Treatment of insomnia characterized by difficulty with sleep maintenance.


Contraindications


Hypersensitivity to doxepin, dibenzoxepins, or any component of the formulation; glaucoma; urinary retention; use of MAO inhibitors within 14 days

Documentation of allergenic cross-reactivity for tricyclic antidepressants is limited. However, because of similarities in chemical structure and/or pharmacologic actions, the possibility of cross-sensitivity cannot be ruled out with certainty.


ALERT: U.S. Boxed Warning

Suicidality and antidepressant drugs:

Antidepressants increased the risk of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults in short-term studies of major depressive disorder (MDD) and other psychiatric disorders. Anyone considering the use of doxepin or any other antidepressant in a child, adolescent, or young adult must balance this risk with the clinical need. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared with placebo in adults older than 24 years; there was a reduction in risk with antidepressants compared with placebo in adults 65 years and older. Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. Appropriately monitor patients of all ages who are started on antidepressant therapy and observe closely for clinical worsening, suicidality, or unusual changes in behavior. Advise families and caregivers of the need for close observation and communication with the health care provider. Doxepin is not approved for use in pediatric patients.


Dosing and Administration


Dosing: Adult

Depression and/or anxiety: Oral: Initial: 25 to 50 mg as a single dose at bedtime or in divided doses; gradually increase based on response and tolerability to a usual dose of 100-300 mg daily (APA 2010; Bauer 2013)

Insomnia (Silenor): Oral: 3 to 6 mg once daily within 30 minutes of bedtime; maximum dose: 6 mg daily

Chronic urticaria (off-label use): Oral: Adults: 10 mg 3 times daily (Greene, 1985) or 10 mg to 30 mg once daily at bedtime (Yadav 2009)

Discontinuation of therapy: Upon discontinuation of antidepressant therapy, gradually taper the dose to minimize the incidence of withdrawal symptoms and allow for the detection of re-emerging symptoms. Evidence supporting ideal taper rates is limited. APA and NICE guidelines suggest tapering therapy over at least several weeks with consideration to the half-life of the antidepressant; antidepressants with a shorter half-life may need to be tapered more conservatively. In addition for long-term treated patients, WFSBP guidelines recommend tapering over 4 to 6 months. If intolerable withdrawal symptoms occur following a dose reduction, consider resuming the previously prescribed dose and/or decrease dose at a more gradual rate (APA, 2010; Bauer 2002; Haddad 2001; NCCMH 2010; Schatzberg 2006; Shelton 2001; Warner 2006).

MAO inhibitor recommendations:

Switching to or from an MAO inhibitor intended to treat psychiatric disorders:

Allow 14 days to elapse between discontinuing an MAO inhibitor intended to treat psychiatric disorders and initiation of doxepin.

Allow 14 days to elapse between discontinuing doxepin and initiation of an MAO inhibitor intended to treat psychiatric disorders.

Use with other MAO inhibitors (such as linezolid or IV methylene blue):

Do not initiate doxepin in patients receiving linezolid or IV methylene blue; consider other interventions for psychiatric condition.

If urgent treatment with linezolid or IV methylene blue is required in a patient already receiving doxepin and potential benefits outweigh potential risks, discontinue doxepin promptly and administer linezolid or IV methylene blue. Monitor for serotonin syndrome for 2 weeks or until 24 hours after the last dose of linezolid or IV methylene blue, whichever comes first. May resume doxepin 24 hours after the last dose of linezolid or IV methylene blue.


Dosing: Geriatric

Depression and/or anxiety: Oral: Carefully adjust the use of doxepin on a once-a-day dosage regimen in elderly patients based on the patients condition; elderly patients generally should be started on low doses of doxepin and observed closely. Avoid doses >6 mg/day (Beers Criteria [AGS 2015]).

Insomnia: Oral: 3 mg once daily within 30 minutes of bedtime; increase to 6 mg once daily if clinically needed; maximum dose: 6 mg daily. Avoid doses >6 mg/day (Beers Criteria [AGS 2015]).

Discontinuation of therapy: Refer to adult dosing.

MAO inhibitor recommendations: Refer to adult dosing.


Dosing: Renal Impairment

There are no dosage adjustments provided in manufacturer 's labeling.


Dosing: Hepatic Impairment

Silenor: Initial: 3 mg once daily


Reconstitution

Concentrate, oral: Must dilute with approximately 120 mL of water, whole or skimmed milk, or orange, grapefruit, tomato, prune or pineapple juice prior to administration. Do not mix with carbonated beverages (physically incompatible). Doxepin concentrate and methadone syrup can be mixed together with Gatorade, lemon or orange juice, sugar water, Tang, or water, but not with grape juice.


Administration

Depression and/or anxiety: Oral: Administer the total daily dosage in divided or once a day dosage schedule. If the once a day schedule is employed the maximum recommended dose is 150 mg once daily at bedtime. The 150 mg capsule strength is intended for maintenance therapy only and is not for initiation of treatment.

Insomnia: Oral: Administer within 30 minutes prior to bedtime; do not take within 3 hours of food.


Storage

Store at room temperature. Protect from light.


Dosage Forms/Strengths


Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Capsule, Oral:

Generic: 10 mg, 25 mg, 50 mg, 75 mg, 100 mg, 150 mg

Concentrate, Oral:

Generic: 10 mg/mL (118 mL, 120 mL)

Tablet, Oral:

Silenor: 3 mg [contains brilliant blue fcf (fd&c blue #1)]

Silenor: 6 mg [contains brilliant blue fcf (fd&c blue #1), fd&c yellow #10 (quinoline yellow)]


Drug Interactions

Abiraterone Acetate: May increase the serum concentration of CYP2D6 Substrates. Management: Avoid concurrent use of abiraterone with CYP2D6 substrates that have a narrow therapeutic index whenever possible. When concurrent use is not avoidable, monitor patients closely for signs/symptoms of toxicity. Consider therapy modification

AbobotulinumtoxinA: Anticholinergic Agents may enhance the anticholinergic effect of AbobotulinumtoxinA. Monitor therapy

Acetylcholinesterase Inhibitors: May diminish the therapeutic effect of Anticholinergic Agents. Anticholinergic Agents may diminish the therapeutic effect of Acetylcholinesterase Inhibitors. Monitor therapy

Aclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Alcohol (Ethyl): CNS Depressants may enhance the CNS depressant effect of Alcohol (Ethyl). Monitor therapy

Alpha-/Beta-Agonists (Direct-Acting): Tricyclic Antidepressants may enhance the vasopressor effect of Alpha-/Beta-Agonists (Direct-Acting). Management: Avoid, if possible, the use of direct-acting alpha-/beta-agonists in patients receiving tricyclic antidepressants. If combined, monitor for evidence of increased pressor effects and consider reductions in initial dosages of the alpha-/beta-agonist. Exceptions: Dipivefrin. Consider therapy modification

Alpha1-Agonists: Tricyclic Antidepressants may enhance the vasopressor effect of Alpha1-Agonists. Tricyclic Antidepressants may diminish the vasopressor effect of Alpha1-Agonists. Monitor therapy

Alpha2-Agonists: Tricyclic Antidepressants may diminish the antihypertensive effect of Alpha2-Agonists. Exceptions: Apraclonidine; Brimonidine (Ophthalmic). Consider therapy modification

Alpha2-Agonists (Ophthalmic): Tricyclic Antidepressants may diminish the therapeutic effect of Alpha2-Agonists (Ophthalmic). Monitor therapy

Altretamine: May enhance the orthostatic hypotensive effect of Tricyclic Antidepressants. Monitor therapy

Amphetamines: Tricyclic Antidepressants may enhance the stimulatory effect of Amphetamines. Tricyclic Antidepressants may also potentiate the cardiovascular effects of Amphetamines. Monitor therapy

Analgesics (Opioid): Anticholinergic Agents may enhance the adverse/toxic effect of Analgesics (Opioid). Specifically, the risk for constipation and urinary retention may be increased with this combination. Monitor therapy

Analgesics (Opioid): May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

Anticholinergic Agents: May enhance the adverse/toxic effect of other Anticholinergic Agents. Monitor therapy

Antiemetics (5HT3 Antagonists): May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

Antipsychotic Agents: Serotonin Modulators may enhance the adverse/toxic effect of Antipsychotic Agents. Specifically, serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotic Agents may enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

Aspirin: Antidepressants (Tricyclic, Tertiary Amine) may enhance the antiplatelet effect of Aspirin. Monitor therapy

Asunaprevir: May increase the serum concentration of CYP2D6 Substrates. Consider therapy modification

Azelastine (Nasal): CNS Depressants may enhance the CNS depressant effect of Azelastine (Nasal). Avoid combination

Barbiturates: May increase the metabolism of Tricyclic Antidepressants. Consider therapy modification

Beta2-Agonists: Tricyclic Antidepressants may enhance the adverse/toxic effect of Beta2-Agonists. Monitor therapy

Blonanserin: CNS Depressants may enhance the CNS depressant effect of Blonanserin. Consider therapy modification

Brimonidine (Topical): May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Buprenorphine: CNS Depressants may enhance the CNS depressant effect of Buprenorphine. Management: Consider reduced doses of other CNS depressants, and avoiding such drugs in patients at high risk of buprenorphine overuse/self-injection. Initiate buprenorphine patches (Butrans brand) at 5 mcg/hr in adults when used with other CNS depressants. Consider therapy modification

BuPROPion: May decrease the metabolism of Tricyclic Antidepressants. Management: Seek alternatives when possible. Monitor patients receiving these combinations closely for increased serum concentrations (when testing is available) and toxic effects of the tricyclic antidepressant. Consider therapy modification

Cannabis: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

CarBAMazepine: May increase the metabolism of Tricyclic Antidepressants. Monitor therapy

Cimetidine: May decrease the metabolism of Tricyclic Antidepressants. Monitor therapy

Cimetropium: Anticholinergic Agents may enhance the anticholinergic effect of Cimetropium. Avoid combination

Cinacalcet: May increase the serum concentration of Tricyclic Antidepressants. Management: Seek alternatives when possible. If these combinations are used, monitor closely for increased effects/toxicity and/or elevated serum concentrations (when testing is available) of the tricyclic antidepressant. Consider therapy modification

Citalopram: Tricyclic Antidepressants may enhance the adverse/toxic effect of Citalopram. Tricyclic Antidepressants may increase the serum concentration of Citalopram. Citalopram may increase the serum concentration of Tricyclic Antidepressants. Management: Consider alternatives to this combination when possible. Monitor for adverse effects of tricyclic antidepressants (TCAs), including serotonin syndrome and QT-interval prolongation, when a TCA is being used in combination with citalopram. Consider therapy modification

CNS Depressants: May enhance the adverse/toxic effect of other CNS Depressants. Monitor therapy

Cobicistat: May increase the serum concentration of CYP2D6 Substrates. Monitor therapy

CYP2D6 Inhibitors (Moderate): May decrease the metabolism of CYP2D6 Substrates. Monitor therapy

CYP2D6 Inhibitors (Strong): May decrease the metabolism of CYP2D6 Substrates. Consider therapy modification

Dapoxetine: May enhance the adverse/toxic effect of Serotonin Modulators. Avoid combination

Darunavir: May increase the serum concentration of CYP2D6 Substrates. Monitor therapy

Desmopressin: Tricyclic Antidepressants may enhance the adverse/toxic effect of Desmopressin. Monitor therapy

Dexmethylphenidate: May enhance the adverse/toxic effect of Tricyclic Antidepressants. Dexmethylphenidate may increase the serum concentration of Tricyclic Antidepressants. Monitor therapy

Dimethindene: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Doxylamine: May enhance the CNS depressant effect of CNS Depressants. Management: The manufacturer of Diclegis (doxylamine/pyridoxine), intended for use in pregnancy, specifically states that use with other CNS depressants is not recommended. Monitor therapy

Dronabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Dronedarone: Tricyclic Antidepressants may enhance the arrhythmogenic effect of Dronedarone. Avoid combination

Droperidol: May enhance the CNS depressant effect of CNS Depressants. Management: Consider dose reductions of droperidol or of other CNS agents (e.g., opioids, barbiturates) with concomitant use. Consider therapy modification

DULoxetine: May enhance the serotonergic effect of Tricyclic Antidepressants. This could result in serotonin syndrome. DULoxetine may decrease the metabolism of Tricyclic Antidepressants. Management: Use these drugs in combination with caution. Monitor closely for signs and symptoms of serotonin toxicity/serotonin syndrome. Consider therapy modification

Eluxadoline: Anticholinergic Agents may enhance the constipating effect of Eluxadoline. Avoid combination

Escitalopram: Tricyclic Antidepressants may enhance the adverse/toxic effect of Escitalopram. Escitalopram may increase the serum concentration of Tricyclic Antidepressants. Management: Consider alternatives to this combination when possible. Monitor for adverse effects of tricyclic antidepressants (TCAs), including serotonin syndrome and QT-interval prolongation, when a TCA is being used in combination with escitalopram. Consider therapy modification

Flunitrazepam: CNS Depressants may enhance the CNS depressant effect of Flunitrazepam. Consider therapy modification

FLUoxetine: May enhance the adverse/toxic effect of Tricyclic Antidepressants. FLUoxetine may increase the serum concentration of Tricyclic Antidepressants. Management: Consider alternatives to this combination when possible. Monitor for adverse effects of tricyclic antidepressants (TCAs), including serotonin syndrome and QT-interval prolongation, when a TCA is being used in combination with fluoxetine. Consider therapy modification

FluvoxaMINE: May enhance the adverse/toxic effect of Tricyclic Antidepressants. FluvoxaMINE may increase the serum concentration of Tricyclic Antidepressants. Management: Consider alternatives to this combination when possible. Monitor for adverse effects of tricyclic antidepressants (TCAs), including serotonin syndrome and QT-interval prolongation, when a TCA is being used in combination with fluvoxamine. Consider therapy modification

Gastrointestinal Agents (Prokinetic): Anticholinergic Agents may diminish the therapeutic effect of Gastrointestinal Agents (Prokinetic). Monitor therapy

Glucagon: Anticholinergic Agents may enhance the adverse/toxic effect of Glucagon. Specifically, the risk of gastrointestinal adverse effects may be increased. Avoid combination

Glycopyrrolate (Oral Inhalation): Anticholinergic Agents may enhance the anticholinergic effect of Glycopyrrolate (Oral Inhalation). Avoid combination

Highest Risk QTc-Prolonging Agents: QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying) may enhance the QTc-prolonging effect of Highest Risk QTc-Prolonging Agents. Management: Avoid such combinations when possible. Use should be accompanied by close monitoring for evidence of QT prolongation or other alterations of cardiac rhythm. Consider therapy modification

HYDROcodone: CNS Depressants may enhance the CNS depressant effect of HYDROcodone. Management: Consider starting with a 20% to 30% lower hydrocodone dose when using together with any other CNS depressant. Dose reductions in the other CNS depressant may also be warranted. Consider therapy modification

HydrOXYzine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Iobenguane I 123: Tricyclic Antidepressants may diminish the therapeutic effect of Iobenguane I 123. Avoid combination

Ipratropium (Oral Inhalation): May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Itopride: Anticholinergic Agents may diminish the therapeutic effect of Itopride. Monitor therapy

Kava Kava: May enhance the adverse/toxic effect of CNS Depressants. Monitor therapy

Levosulpiride: Anticholinergic Agents may diminish the therapeutic effect of Levosulpiride. Avoid combination

Linezolid: May enhance the serotonergic effect of Tricyclic Antidepressants. This could result in serotonin syndrome. Avoid combination

Lithium: May enhance the neurotoxic effect of Tricyclic Antidepressants. Management: This combination should be undertaken with great caution. When combined treatment is clinically indicated, monitor closely for signs of serotonin toxicity/serotonin syndrome. Consider therapy modification

Magnesium Sulfate: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

MAO Inhibitors: May enhance the serotonergic effect of Tricyclic Antidepressants. This may cause serotonin syndrome. While methylene blue and linezolid are expected to interact via this mechanism, management recommendations differ from other monoamine oxidase inhibitors. Refer to monographs specific to those agents for details. Exceptions: Linezolid; Methylene Blue; Tedizolid. Avoid combination

Metaxalone: May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

Methotrimeprazine: CNS Depressants may enhance the CNS depressant effect of Methotrimeprazine. Methotrimeprazine may enhance the CNS depressant effect of CNS Depressants. Management: Reduce adult dose of CNS depressant agents by 50% with initiation of concomitant methotrimeprazine therapy. Further CNS depressant dosage adjustments should be initiated only after clinically effective methotrimeprazine dose is established. Consider therapy modification

Methylene Blue: Tricyclic Antidepressants may enhance the serotonergic effect of Methylene Blue. This could result in serotonin syndrome. Avoid combination

Methylene Blue: May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Avoid combination

Methylphenidate: May enhance the adverse/toxic effect of Tricyclic Antidepressants. Methylphenidate may increase the serum concentration of Tricyclic Antidepressants. Monitor therapy

Metoclopramide: May enhance the adverse/toxic effect of Tricyclic Antidepressants. Management: Seek alternatives to this combination when possible. Monitor patients receiving metoclopramide with tricyclic antidepressants for signs of extrapyramidal symptoms, neuroleptic malignant syndrome, and serotonin syndrome. Consider therapy modification

MetyroSINE: CNS Depressants may enhance the sedative effect of MetyroSINE. Monitor therapy

MetyroSINE: May enhance the adverse/toxic effect of Tricyclic Antidepressants. Monitor therapy

Mianserin: May enhance the anticholinergic effect of Anticholinergic Agents. Monitor therapy

MiFEPRIStone: May enhance the QTc-prolonging effect of QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying). Management: Though the drugs listed here have uncertain QT-prolonging effects, they all have some possible association with QT prolongation and should generally be avoided when possible. Consider therapy modification

Minocycline: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Mirabegron: Anticholinergic Agents may enhance the adverse/toxic effect of Mirabegron. Monitor therapy

Mirtazapine: CNS Depressants may enhance the CNS depressant effect of Mirtazapine. Monitor therapy

Moderate Risk QTc-Prolonging Agents: QTc-Prolonging Agents (Indeterminate Risk and Risk Modifying) may enhance the QTc-prolonging effect of Moderate Risk QTc-Prolonging Agents. Monitor therapy

Moxonidine: Tricyclic Antidepressants may diminish the therapeutic effect of Moxonidine. Avoid combination

Nabilone: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Nicorandil: Tricyclic Antidepressants may enhance the hypotensive effect of Nicorandil. Monitor therapy

NSAID (COX-2 Inhibitor): Antidepressants (Tricyclic, Tertiary Amine) may enhance the antiplatelet effect of NSAID (COX-2 Inhibitor). Monitor therapy

NSAID (Nonselective): Antidepressants (Tricyclic, Tertiary Amine) may enhance the antiplatelet effect of NSAID (Nonselective). Monitor therapy

OnabotulinumtoxinA: Anticholinergic Agents may enhance the anticholinergic effect of OnabotulinumtoxinA. Monitor therapy

Orphenadrine: CNS Depressants may enhance the CNS depressant effect of Orphenadrine. Avoid combination

Oxatomide: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

OxyCODONE: CNS Depressants may enhance the CNS depressant effect of OxyCODONE. Management: When oxycodone is combined with another CNS depressant, a dose reduction of one or both agents should be considered. The extended release oxycodone starting dose should be reduced 50% to 67% when initiated in patients already receiving CNS depressants. Consider therapy modification

Panobinostat: May increase the serum concentration of CYP2D6 Substrates. Management: Avoid concurrent use of sensitive CYP2D6 substrates when possible, particularly those substrates with a narrow therapeutic index. Consider therapy modification

Paraldehyde: CNS Depressants may enhance the CNS depressant effect of Paraldehyde. Avoid combination

PARoxetine: May enhance the adverse/toxic effect of Tricyclic Antidepressants. PARoxetine may increase the serum concentration of Tricyclic Antidepressants. Management: Consider alternatives to this combination when possible. Monitor for adverse effects of tricyclic antidepressants (TCAs), including serotonin syndrome and QT-interval prolongation, when a TCA is being used in combination with paroxetine. Consider therapy modification

Peginterferon Alfa-2b: May decrease the serum concentration of CYP2D6 Substrates. Peginterferon Alfa-2b may increase the serum concentration of CYP2D6 Substrates. Monitor therapy

Perampanel: May enhance the CNS depressant effect of CNS Depressants. Management: Patients taking perampanel with any other drug that has CNS depressant activities should avoid complex and high-risk activities, particularly those such as driving that require alertness and coordination, until they have experience using the combination. Consider therapy modification

Perhexiline: CYP2D6 Substrates may increase the serum concentration of Perhexiline. Perhexiline may increase the serum concentration of CYP2D6 Substrates. Monitor therapy

Piribedil [INT]: CNS Depressants may enhance the CNS depressant effect of Piribedil [INT]. Monitor therapy

Potassium Chloride: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Chloride. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium chloride. Avoid combination

Pramipexole: CNS Depressants may enhance the sedative effect of Pramipexole. Monitor therapy

Pramlintide: May enhance the anticholinergic effect of Anticholinergic Agents. These effects are specific to the GI tract. Consider therapy modification

Protease Inhibitors: May increase the serum concentration of Tricyclic Antidepressants. Monitor therapy

QuiNIDine: Tricyclic Antidepressants may enhance the QTc-prolonging effect of QuiNIDine. QuiNIDine may increase the serum concentration of Tricyclic Antidepressants. Consider therapy modification

Ramosetron: Anticholinergic Agents may enhance the constipating effect of Ramosetron. Monitor therapy

RimabotulinumtoxinB: Anticholinergic Agents may enhance the anticholinergic effect of RimabotulinumtoxinB. Monitor therapy

ROPINIRole: CNS Depressants may enhance the sedative effect of ROPINIRole. Monitor therapy

Rotigotine: CNS Depressants may enhance the sedative effect of Rotigotine. Monitor therapy

Rufinamide: May enhance the adverse/toxic effect of CNS Depressants. Specifically, sleepiness and dizziness may be enhanced. Monitor therapy

Secretin: Anticholinergic Agents may diminish the therapeutic effect of Secretin. Management: Avoid using drugs with substantial anticholinergic effects in patients receiving secretin whenever possible. If such agents must be used in combination, monitor closely for a diminished response to secretin. Consider therapy modification

Selective Serotonin Reuptake Inhibitors: CNS Depressants may enhance the adverse/toxic effect of Selective Serotonin Reuptake Inhibitors. Specifically, the risk of psychomotor impairment may be enhanced. Monitor therapy

Serotonin Modulators: May enhance the adverse/toxic effect of other Serotonin Modulators. The development of serotonin syndrome may occur. Exceptions: Nicergoline; Tedizolid. Monitor therapy

Sertraline: May enhance the adverse/toxic effect of Tricyclic Antidepressants. Sertraline may increase the serum concentration of Tricyclic Antidepressants. Management: Consider alternatives to this combination when possible. Monitor for adverse effects of tricyclic antidepressants (TCAs), including serotonin syndrome and QT-interval prolongation, when a TCA is being used in combination with sertraline. Consider therapy modification

Sodium Oxybate: May enhance the CNS depressant effect of CNS Depressants. Management: Consider alternatives to combined use. When combined use is needed, consider minimizing doses of one or more drugs. Use of sodium oxybate with alcohol or sedative hypnotics is contraindicated. Consider therapy modification

Sodium Phosphates: Tricyclic Antidepressants may enhance the adverse/toxic effect of Sodium Phosphates. Specifically, the risk of seizure and/or loss of consciousness may be increased in patients with significant sodium phosphate induced fluid/electrolyte abnormalities. Monitor therapy

St Johns Wort: May increase the metabolism of Tricyclic Antidepressants. The risk of serotonin syndrome may theoretically be increased. Consider therapy modification

Sulfonylureas: Cyclic Antidepressants may enhance the hypoglycemic effect of Sulfonylureas. Monitor therapy

Suvorexant: CNS Depressants may enhance the CNS depressant effect of Suvorexant. Management: Dose reduction of suvorexant and/or any other CNS depressant may be necessary. Use of suvorexant with alcohol is not recommended, and the use of suvorexant with any other drug to treat insomnia is not recommended. Consider therapy modification

Tapentadol: May enhance the CNS depressant effect of CNS Depressants. Management: Start tapentadol at a dose of one-third to one-half of the normal dose if being initiated in a patient who is taking another drug with CNS depressant effects. Monitor closely for evidence of excessive CNS depression. Consider therapy modification

Tedizolid: May enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

Tetrahydrocannabinol: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Thalidomide: CNS Depressants may enhance the CNS depressant effect of Thalidomide. Avoid combination

Thiazide and Thiazide-Like Diuretics: Anticholinergic Agents may increase the serum concentration of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Thyroid Products: May enhance the arrhythmogenic effect of Tricyclic Antidepressants. Thyroid Products may enhance the stimulatory effect of Tricyclic Antidepressants. Monitor therapy

Tiotropium: Anticholinergic Agents may enhance the anticholinergic effect of Tiotropium. Avoid combination

Topiramate: Anticholinergic Agents may enhance the adverse/toxic effect of Topiramate. Monitor therapy

TraMADol: Serotonin Modulators may enhance the adverse/toxic effect of TraMADol. The risk of seizures may be increased. TraMADol may enhance the serotonergic effect of Serotonin Modulators. This could result in serotonin syndrome. Monitor therapy

Trimeprazine: May enhance the CNS depressant effect of CNS Depressants. Monitor therapy

Umeclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Valproate Products: May increase the serum concentration of Tricyclic Antidepressants. Monitor therapy

Vitamin K Antagonists (eg, warfarin): Tricyclic Antidepressants may enhance the anticoagulant effect of Vitamin K Antagonists. Monitor therapy

Yohimbine: Tricyclic Antidepressants may increase the serum concentration of Yohimbine. Monitor therapy

Zolpidem: CNS Depressants may enhance the CNS depressant effect of Zolpidem. Management: Reduce the Intermezzo brand sublingual zolpidem adult dose to 1.75 mg for men who are also receiving other CNS depressants. No such dose change is recommended for women. Avoid use with other CNS depressants at bedtime; avoid use with alcohol. Consider therapy modification


Monitoring Parameters

Evaluate mental status, suicide ideation (especially at the beginning of therapy or when doses are increased or decreased); anxiety, social functioning, mania, panic attacks or other unusual changes in behavior; heart rate, blood pressure and ECG in older adults and patients with preexisting cardiac disease; blood glucose; weight and BMI; blood levels are useful for therapeutic monitoring (APA 2010).

Insomnia: Re-evaluate diagnosis if insomnia does not remit within 7-10 days of treatment.


Adverse Reactions


Actual frequency may be dependent on diagnosis.

Cardiovascular: Hypertension (chronic insomnia patients ≤3%), edema, flushing, hypotension, tachycardia

Central nervous system: Sedation (chronic insomnia patients 6% to 9%), dizziness (chronic insomnia patients ≥1%), ataxia, chills, confusion, disorientation, drowsiness, extrapyramidal reaction, fatigue, hallucination, headache, numbness, paresthesia, seizure, tardive dyskinesia

Dermatologic: Alopecia, diaphoresis (excessive), pruritus, skin photosensitivity, skin rash

Endocrine & metabolic: Altered serum glucose, change in libido, galactorrhea, gynecomastia, SIADH, weight gain

Gastrointestinal: Nausea (chronic insomnia patients 2%), gastroenteritis (chronic insomnia patients ≤2%), anorexia, aphthous stomatitis, constipation, diarrhea, dysgeusia, dyspepsia, vomiting, xerostomia

Genitourinary: Breast hypertrophy, testicular swelling, urinary retention

Hematologic & oncologic: Agranulocytosis, eosinophilia, leukopenia, purpura, thrombocytopenia

Hepatic: Jaundice

Neuromuscular & skeletal: Tremor, weakness

Ophthalmic: Blurred vision

Otic: Tinnitus

Respiratory: Upper respiratory tract infection (chronic insomnia patients 4%), exacerbation of asthma

<1% (Limited to important or life-threatening): Adenocarcinoma (lung, stage I), adjustment disorder, anemia, angle-closure glaucoma, atrioventricular block, bone fracture, breast cyst, cerebrovascular accident, chest pain, decreased neutrophils, decreased performance on neuropsychometrics, decreased range of motion (joints), depression, ECG abnormality (ST-T segment, QRS complex, QRS axis), eye infection, fungal infection, gastroesophageal reflux disease, hematochezia, hematoma, hemoglobinuria, hyperbilirubinemia, hyperkalemia, hypermagnesemia, hypersensitivity, hypoacusis, hypokalemia, increased serum ALT, increased serum transaminases, malignant melanoma, migraine, peripheral edema, pneumonia, sleep paralysis, somnambulism (complex sleep-related behavior [sleep-driving, cooking or eating food, making phone calls]), staphylococcal cellulitis, syncope, tenosynovitis, tooth infection, urinary incontinence, urinary tract infection, viral infection


Warnings/Precautions


Special Populations: Hepatic Function Impairment

Patients with hepatic impairment may display higher doxepin concentrations than healthy individuals.


Warnings/Precautions

Major psychiatric warnings:

- Suicidal thinking/behavior: [US Boxed Warning]: Antidepressants increase the risk of suicidal thinking and behavior in children, adolescents, and young adults (18-24 years of age) with major depressive disorder (MDD) and other psychiatric disorders; consider risk prior to prescribing. Short-term studies did not show an increased risk in patients >24 years of age and showed a decreased risk in patients ≥65 years. Closely monitor patients for clinical worsening, suicidality, or unusual changes in behavior, particularly during the initial 1 to 2 months of therapy or during periods of dosage adjustments (increases or decreases); the patient 's family or caregiver should be instructed to closely observe the patient and communicate condition with healthcare provider. A medication guide concerning the use of antidepressants should be dispensed with each prescription. Doxepin is not approved for use in pediatric patients.

- The possibility of a suicide attempt is inherent in major depression and may persist until remission occurs. Worsening depression and severe abrupt suicidality that are not part of the presenting symptoms may require discontinuation or modification of drug therapy. Use caution in high-risk patients during initiation of therapy.

- Risk of suicidal behavior may be increased regardless of doxepin dose; antidepressant doses of doxepin are 10- to 100-fold higher than doses for insomnia.

- Prescriptions should be written for the smallest quantity consistent with good patient care. The patients family or caregiver should be alerted to monitor patients for the emergence of suicidality and associated behaviors such as anxiety, agitation, panic attacks, insomnia, irritability, hostility, impulsivity, akathisia, hypomania, and mania; patients should be instructed to notify their healthcare provider if any of these symptoms or worsening depression or psychosis occur.

Concerns related to adverse effects:

- Anticholinergic effects: May cause anticholinergic effects (constipation, xerostomia, blurred vision, urinary retention); use with caution in patients with decreased gastrointestinal motility, paralytic ileus, urinary retention, BPH, xerostomia, or visual problems. The degree of anticholinergic blockade produced by this agent is high relative to other antidepressants (APA 2010).

- CNS depression: May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks that require mental alertness (eg, operating machinery or driving).

- CNS effects: Anxiety, psychosis, and other neuropsychiatric symptoms may occur unpredictably.

- Fractures: Bone fractures have been associated with antidepressant treatment. Consider the possibility of a fragility fracture if an antidepressant-treated patient presents with unexplained bone pain, point tenderness, swelling, or bruising (Rabenda 2013; Rizzoli 2012).

- Ocular effects: May cause mild pupillary dilation which in susceptible individuals can lead to an episode of narrow-angle glaucoma. Consider evaluating patients who have not had an iridectomy for narrow-angle glaucoma risk factors.

- Orthostatic hypotension: May cause orthostatic hypotension (risk is moderate relative to other antidepressants); use with caution in patients at risk of this effect or in those who would not tolerate transient hypotensive episodes (cerebrovascular disease, cardiovascular disease, hypovolemia, or concurrent medication use which may predispose to hypotension/bradycardia) (APA 2010).

- Sleep-related activities: An increased risk for hazardous sleep-related activities such as sleep-driving; cooking and eating food, making phone calls, and having sex while asleep have also been noted; amnesia may also occur. Discontinue treatment in patients who report any sleep-related episodes.

Disease-related concerns:

- Cardiovascular disease: Use with caution in patients with a history of cardiovascular disease (including previous MI, stroke, tachycardia, or conduction abnormalities); the risk conduction abnormalities with this agent is moderate relative to other antidepressants (APA 2010).

- Diabetes: Use with caution in patients with diabetes mellitus; may alter glucose regulation (APA 2010).

- Hepatic impairment: Use with caution in patients with hepatic impairment; higher doxepin concentrations may occur.

- Mania/hypomania: May precipitate a shift to mania or hypomania in patients with bipolar disorder. Monotherapy in patients with bipolar disorder should be avoided. Patients presenting with depressive symptoms should be screened for bipolar disorder, including details regarding family history of suicide, bipolar disorder, and depression. Doxepin is not FDA approved for the treatment of bipolar depression.

- Respiratory disease: Use with caution in patients with respiratory compromise or sleep apnea; use of Silenor is generally not recommended in patients with severe sleep apnea.

- Seizure disorder: Use with caution in patients at risk of seizures, including those with a history of seizures, head trauma, brain damage, alcoholism, or concurrent therapy with medications which may lower seizure threshold (APA 2010).

Concurrent drug therapy issues:

- Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

- Elderly: May cause confusion and over sedation in the elderly.

Other warnings/precautions:

- Appropriate use: Symptomatic treatment of insomnia should be initiated only after careful evaluation of potential causes of sleep disturbance. Failure of sleep disturbance to resolve after 7-10 days may indicate psychiatric and/or medical illness.

- Discontinuation syndrome: Abrupt discontinuation or interruption of antidepressant therapy has been associated with a discontinuation syndrome. Symptoms arising may vary with antidepressant however commonly include nausea, vomiting, diarrhea, headaches, lightheadedness, dizziness, diminished appetite, sweating, chills, tremors, paresthesias, fatigue, somnolence, and sleep disturbances (eg, vivid dreams, insomnia). Less common symptoms include electric shock-like sensations, cardiac arrhythmias (more common with tricyclic antidepressants), myalgias, parkinsonism, arthralgias, and balance difficulties. Psychological symptoms may also emerge such as agitation, anxiety, akathisia, panic attacks, irritability, aggressiveness, worsening of mood, dysphoria, mood lability, hyperactivity, mania/hypomania, depersonalization, decreased concentration, slowed thinking, confusion, and memory or concentration difficulties. Greater risks for developing a discontinuation syndrome have been associated with antidepressants with shorter half-lives, longer durations of treatment, and abrupt discontinuation. For antidepressants of short or intermediate half-lives, symptoms may emerge within 2-5 days after treatment discontinuation and last 7-14 days (APA 2010; Fava 2006; Haddad 2001; Shelton 2001; Warner 2006).

- Electroconvulsive therapy: May increase the risks associated with electroconvulsive therapy; consider discontinuing, when possible, prior to ECT treatment (APA 2010).


Pregnancy Risk Factor

C


Pregnancy Considerations

Adverse events were observed in animal reproduction studies. Tricyclic antidepressants may be associated with irritability, jitteriness, and convulsions (rare) in the neonate (Yonkers 2009).

The ACOG recommends that therapy for depression during pregnancy be individualized; treatment should incorporate the clinical expertise of the mental health clinician, obstetrician, primary health care provider, and pediatrician (ACOG 2008). According to the American Psychiatric Association (APA), the risks of medication treatment should be weighed against other treatment options and untreated depression. For women who discontinue antidepressant medications during pregnancy and who may be at high risk for postpartum depression, the medications can be restarted following delivery (APA 2010). Treatment algorithms have been developed by the ACOG and the APA for the management of depression in women prior to conception and during pregnancy (Yonkers 2009).

Pregnant women exposed to antidepressants during pregnancy are encouraged to enroll in the National Pregnancy Registry for Antidepressants (NPRAD). Women 18 to 45 years of age or their health care providers may contact the registry by calling 844-405-6185. Enrollment should be done as early in pregnancy as possible.


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Pharmacology

Increases the synaptic concentration of serotonin and norepinephrine in the central nervous system by inhibition of their reuptake by the presynaptic neuronal membrane (Pinder, 1977); antagonizes the histamine (H1) receptor for sleep maintenance.

Efficacy of doxepin in the off-label use of chronic urticaria is believed to be related to its potent H1 and H2 receptor antagonist activity (Kozel 2004).


Absorption

Administration with a high-fat meal increases the bioavailability of Silenor and delays the peak plasma concentration by ~3 hours


Distribution

Vd: 20.2 L/kg (Ziegler, 1978); Silenor 11,930 L


Metabolism

Hepatic via CYP2C19 and 2D6; metabolites include N-desmethyldoxepin (active)


Excretion

Urine (<3% as unchanged drug or N-desmethyldoxepin)


Onset of Action

Individual responses may vary; 4-8 weeks of treatment are needed before determining if a patient with depression is partially or nonresponsive (APA 2010); onset of anxiolytic effects may have a latency of 2-6 weeks (Bandelow 2008)


Time to Peak

Serum: Fasting: Silenor: 3.5 hours


Half-Life Elimination

Adults: Doxepin: ~15 hours; N-desmethyldoxepin: 31 hours


Protein Binding

~80%


Patient and Family Education


Patient Education

- Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

- Patient may experience fatigue, nausea, vomiting, constipation, or dry mouth. Have patient report immediately to prescriber signs of depression (suicidal ideation, anxiety, emotional instability, or illogical thinking), tachycardia, severe dizziness, passing out, difficult urination, loss of strength and energy, bruising, bleeding, chills, hallucinations, burning or numbness feeling, abnormal movements, twitching, change in balance, dysphagia, difficulty speaking, seizures, jaundice, severe headache, vision changes, eye pain, eye irritation, or decreased libido (HCAHPS).

- Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.

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