(sye MET i deen)
Duodenal ulcer: Short-term treatment of active duodenal ulcer and maintenance therapy after the healing of active ulcer.
Gastric ulcer: Short-term treatment of active, benign gastric ulcer.
Gastroesophageal reflux disease: Treatment of erosive gastroesophageal reflux disease (GERD).
Pathological hypersecretory conditions: Treatment of pathological hypersecretory conditions (eg, Zollinger-Ellison syndrome, systemic mastocytosis, multiple endocrine adenomas).
Heartburn (OTC only): Relief and prevention of heartburn associated with acid indigestion and sour stomach.
Hypersensitivity to cimetidine or any component of the formulation
OTC labeling: When used for self-medication (OTC), do not use if trouble or pain when swallowing food, vomiting with blood, or bloody or black stools, allergic to cimetidine or other acid reducers. Do not use with other acid reducers.
Documentation of allergenic cross-reactivity for histamine H2 antagonists is limited. However, because of similarities in chemical structure and/or pharmacologic actions, the possibility of cross-sensitivity cannot be ruled out with certainty.
Duodenal ulcer, active: Oral: 300 mg 4 times daily or 800 mg at bedtime or 400 mg twice daily for up to 8 weeks
Note: Higher doses of 1600 mg at bedtime for 4 weeks may be beneficial for a subpopulation of patients with larger duodenal ulcers (>1 cm defined endoscopically) who are also heavy smokers ( ≥1 pack/day).
Duodenal ulcer, prophylaxis: 400 mg at bedtime
Gastric ulcer, active: 300 mg 4 times daily or 800 mg at bedtime for up to 8 weeks
Gastroesophageal reflux disease: 400 mg 4 times daily or 800 mg twice daily for 12 weeks
Pathological hypersecretory conditions: 300 mg 4 times daily; adjust dose to patient response; maximum 2.4 g/day
Interstitial cystitis (bladder pain syndrome) (off-label use): 200 mg 3 times daily or 300 to 400 mg twice daily (Dasgupta 2001; Seshadri 1994; Thilagarajah 2001)
Peptic ulcer disease eradication ofHelicobacter pylori(off-label use): 400 mg twice daily; requires combination therapy with antibiotics
Heartburn (OTC labeling):
Prevention: 200 mg daily up to 30 minutes prior to eating foods or beverages that cause heartburn (maximum: 400 mg/24 hours).
Relief of symptoms: 200 mg daily; maximum: 400 mg/24 hours.
Refer to adult dosing.
Children and Adolescents <16 years: Oral: 20 to 40 mg/kg/day (limited experience)
Heartburn (prevention or relief) (OTC labeling): Children ≥12 years and Adolescents: Oral: Refer to adult dosing.
Manufacturers labeling:
Mild to moderate renal impairment: There are no dosage adjustments provided in the manufacturer 's labeling; use with caution.
Severe renal impairment: 300 mg every 12 hours; may increase frequency with caution. When hepatic impairment is also present, further reductions in dosage may be necessary.
Alternate recommendations:
Adults (Aronoff 2007):
GFR >50 mL/minute: No dosage adjustment necessary.
GFR 10 to 50 mL/minute: Administer 50% of normal dose
GFR <10 mL/minute: 300 mg every 8 to 12 hours
Hemodialysis: Dose after dialysis
CCRT: Administer 50% of normal dose
Peritoneal dialysis: 300 mg every 8 to 12 hours
Geriatric patients ≥65 years: CrCl <50 mL/minute: Reduce the dose because of risk of mental status changes (specific dosage adjustment is not provided (Beers Criteria [AGS, 2015]).
There are no dosage adjustments provided in the manufacturer 's labeling; use with caution. Dosage adjustments may be needed in patients with both renal and hepatic impairment.
Administer with meals.
Store at room temperature. Protect from light.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, Oral, as hydrochloride [strength expressed as base]:
Generic: 300 mg/5 mL (237 mL, 240 mL)
Tablet, Oral:
Cimetidine Acid Reducer: 200 mg
Tagamet HB: 200 mg
Generic: 200 mg, 300 mg, 400 mg, 800 mg
Note: Commercial oral solution is available (strength expressed as base: 60 mg/mL)
A 60 mg/mL oral suspension may be made with tablets. Place twenty-four 300 mg tablets in 5 mL of sterile water for ~3-5 minutes to dissolve film coating. Crush tablets in a mortar and reduce to a fine powder. Add 10 mL of glycerin and mix to a uniform paste; mix while adding Simple Syrup, NF in incremental proportions to almost 120 mL; transfer to a calibrated bottle, rinse mortar with vehicle, and add quantity of vehicle sufficient to make 120 mL. Label shake well" and "refrigerate". Stable for 17 days.
Nahata MC, Pai VB, and Hipple TF, Pediatric Drug Formulations, 5th ed, Cincinnati, OH: Harvey Whitney Books Co, 2004.Alfentanil: Cimetidine may increase the serum concentration of Alfentanil. Monitor therapy
Amiodarone: Cimetidine may increase the serum concentration of Amiodarone. Management: Consider alternatives to cimetidine. If this combination cannot be avoided, monitor for increased amiodarone concentrations/effects with cimetidine initiation/dose increase or decreased concentrations/effects with cimetidine discontinuation/dose decrease. Consider therapy modification
ARIPiprazole: CYP3A4 Inhibitors (Weak) may increase the serum concentration of ARIPiprazole. Management: Monitor for increased aripiprazole pharmacologic effects. Aripiprazole dose adjustments may or may not be required based on concomitant therapy and/or indication. Consult full interaction monograph for specific recommendations. Monitor therapy
ARIPiprazole: CYP2D6 Inhibitors (Weak) may increase the serum concentration of ARIPiprazole. Management: Monitor for increased aripiprazole pharmacologic effects. Aripiprazole dose adjustments may or may not be required based on concomitant therapy and/or indication. Consult full interaction monograph for specific recommendations. Monitor therapy
Atazanavir: H2-Antagonists may decrease the serum concentration of Atazanavir. Management: Specific dose limitations and administration guidelines exist; consult full interaction monograph or atazanavir prescribing information. Consider therapy modification
AtorvaSTATin: May enhance the adverse/toxic effect of Cimetidine. Specifically, there is a theoretical potential for enhanced effects on reducing endogenous steroid activity. Monitor therapy
Bosutinib: H2-Antagonists may decrease the serum concentration of Bosutinib. Management: Administer histamine H2 receptor antagonists more than 2 hours before or after bosutinib. Consider therapy modification
Bromazepam: Cimetidine may increase the serum concentration of Bromazepam. Management: Consider use of bromazepam with an H2-antagonist that is not a potent CYP inhibitor (e.g., ranitidine) or alternatively, consider use of cimetidine with a benzodiazepine that does not undergo oxidative metabolism (e.g., lorazepam). Consider therapy modification
BuPROPion: May increase the serum concentration of OCT2 Substrates. Monitor therapy
Calcium Channel Blockers: Cimetidine may increase the serum concentration of Calcium Channel Blockers. Management: Consider alternatives to cimetidine. If no suitable alternative exists, monitor for increased effects of calcium channel blockers following cimetidine initiation/dose increase, and decreased effects following cimetidine discontinuation/dose decrease. Exceptions: AmLODIPine; Clevidipine; NiCARdipine. Consider therapy modification
Capecitabine: Cimetidine may increase serum concentrations of the active metabolite(s) of Capecitabine. Specifically, concentrations of fluorouracil may be increased. Monitor therapy
CarBAMazepine: Cimetidine may increase the serum concentration of CarBAMazepine. The serum carbamazepine concentration might return to normal within one week of starting cimetidine. Monitor therapy
Carmustine: Cimetidine may enhance the myelosuppressive effect of Carmustine. Management: Consider alternatives to cimetidine in patients receiving carmustine. If the combination cannot be avoided, monitor for enhanced carmustine myelotoxicity. Consider therapy modification
Carvedilol: Cimetidine may increase the serum concentration of Carvedilol. Monitor therapy
Cefditoren: H2-Antagonists may decrease the serum concentration of Cefditoren. Management: Concomitant use of cefditoren with H2-antagonists and antacids is not recommended. Consider alternative methods to control acid reflux (eg, diet modification) or alternative antimicrobial therapy if use of H2-antagonists can not be avoided. Consider therapy modification
Cefpodoxime: H2-Antagonists may decrease the absorption of Cefpodoxime. Separate oral doses by at least 2 hours. Monitor therapy
Cefuroxime: H2-Antagonists may decrease the absorption of Cefuroxime. Separate oral doses by at least 2 hours. Monitor therapy
Cilostazol: CYP2C19 Inhibitors may increase the serum concentration of Cilostazol. Management: Consider reducing the cilostazol dose to 50 mg twice daily in patients who are also receiving inhibitors of CYP2C19. Consider therapy modification
Cisapride: Cimetidine may increase the serum concentration of Cisapride. Management: Consider alternatives to cimetidine. If this combination cannot be avoided, monitor for toxic effects of cisapride if cimetidine is initiated/dose increased, or decreased efficacy if cimetidine is discontinued/dose decreased. Consider therapy modification
Citalopram: CYP2C19 Inhibitors (Moderate) may increase the serum concentration of Citalopram. Management: Limit citalopram dose to a maximum of 20 mg/day if used with a moderate CYP2C19 inhibitor. Patients using this combination should be monitored closely for evidence of citalopram toxicity (e.g., serotonin syndrome, QT prolongation, etc.). Consider therapy modification
Clopidogrel: CYP2C19 Inhibitors (Moderate) may decrease serum concentrations of the active metabolite(s) of Clopidogrel. Management: Due to a risk for impaired clopidogrel effectiveness with such a combination, carefully consider the need for a moderate CYP2C19 inhibitor in patients receiving clopidogrel. Monitor patients closely for evidence of a diminished response to clopidogrel. Consider therapy modification
CloZAPine: Cimetidine may increase the serum concentration of CloZAPine. Management: Consider use of an alternative H2 antagonist. Monitor for increased toxic effects of clozapine if cimetidine is initiated/dose increased, or decreased effects if cimetidine is discontinued/dose decreased. Consider therapy modification
CYP2C19 Substrates: CYP2C19 Inhibitors (Moderate) may decrease the metabolism of CYP2C19 Substrates. Monitor therapy
Cysteamine (Systemic): H2-Antagonists may diminish the therapeutic effect of Cysteamine (Systemic). Monitor therapy
Dabrafenib: H2-Antagonists may decrease the serum concentration of Dabrafenib. Monitor therapy
Dalfampridine: Cimetidine may increase the serum concentration of Dalfampridine. Management: Recommendations differ significantly between international labelings in regards to the concomitant use of dalfampridine (referred to as fampridine in Canada) and cimetidine. Consult appropriate product labeling. Monitor therapy
Dasatinib: H2-Antagonists may decrease the absorption of Dasatinib. Management: Antacids (taken 2 hours before or after dasatinib administration) can be used in place of H2-antagonists if some acid-reducing therapy is needed. Avoid combination
Delavirdine: H2-Antagonists may decrease the serum concentration of Delavirdine. Management: Chronic therapy with H2-antagonists should be avoided in patients who are being treated with delavirdine. The clinical significance of short-term H2-antagonist therapy with delavirdine is uncertain, but such therapy should be undertaken with caution. Avoid combination
Dexmethylphenidate: H2-Antagonists may increase the absorption of Dexmethylphenidate. Specifically, H2-antagonists may interfere with the normal release of drug from the extended-release capsules (Focalin XR brand), which could result in both increased absorption (early) and decreased delayed absorption. Monitor therapy
Dofetilide: Cimetidine may increase the serum concentration of Dofetilide. This is likely via inhibition of dofetilide renal tubular secretion (primarily) and inhibition of dofetilide metabolism. Avoid combination
Doxofylline: Cimetidine may increase the serum concentration of Doxofylline. Monitor therapy
EpiRUBicin: Cimetidine may increase the serum concentration of EpiRUBicin. Avoid combination
Erlotinib: H2-Antagonists may decrease the serum concentration of Erlotinib. Management: Avoid H2-antagonists in patients receiving erlotinib when possible. If concomitant treatment cannot be avoided, erlotinib should be dosed once daily, 10 hours after and at least 2 hours before H2-antagonist dosing. Consider therapy modification
Escitalopram: Cimetidine may increase the serum concentration of Escitalopram. Management: Consider using an alternative H2-antagonist to avoid the risk of escitalopram toxicity. Escitalopram Canadian product labeling recommends limiting escitalopram dose to 10 mg/day with concomitant use of cimetidine. Consider therapy modification
Flibanserin: CYP3A4 Inhibitors (Weak) may increase the serum concentration of Flibanserin. Monitor therapy
Floxuridine: Cimetidine may increase serum concentrations of the active metabolite(s) of Floxuridine. Specifically, concentrations of fluorouracil may be increased. Monitor therapy
Flunitrazepam: Cimetidine may increase the serum concentration of Flunitrazepam. Monitor therapy
Fluorouracil (Systemic): Cimetidine may increase the serum concentration of Fluorouracil (Systemic). Monitor therapy
Fosamprenavir: H2-Antagonists may decrease the serum concentration of Fosamprenavir. Cimetidine may also inhibit the metabolism of the active metabolite amprenavir, making its effects on fosamprenavir/amprenavir concentrations difficult to predict. Monitor therapy
Fosphenytoin-Phenytoin: Cimetidine may enhance the adverse/toxic effect of Fosphenytoin-Phenytoin. Cimetidine may increase the serum concentration of Fosphenytoin-Phenytoin. Management: Consider using an alternative H2-antagonist to avoid this interaction. Monitor for toxic effects of hydantoin anticonvulsants if cimetidine is initiated/dose increased. Consider therapy modification
Gefitinib: H2-Antagonists may decrease the serum concentration of Gefitinib. Management: Administer gefitinib at least 6 hours before or after administration of a histamine H2-antagonist, and closely monitor clinical response to gefitinib. Consider therapy modification
HYDROcodone: CYP3A4 Inhibitors (Weak) may increase the serum concentration of HYDROcodone. Monitor therapy
Indinavir: H2-Antagonists may decrease the serum concentration of Indinavir. Monitor therapy
Iron Salts: H2-Antagonists may decrease the absorption of Iron Salts. Exceptions: Ferric Carboxymaltose; Ferric Citrate; Ferric Gluconate; Ferric Hydroxide Polymaltose Complex; Ferric Pyrophosphate Citrate; Ferumoxytol; Iron Dextran Complex; Iron Sucrose. Monitor therapy
Itraconazole: H2-Antagonists may decrease the serum concentration of Itraconazole. Management: When this combination is used, the itraconazole should be administered with a cola beverage (8 ounces). Itraconazole oral suspension may be less sensitive to this interaction. Monitor patient response to itraconazole closely. Consider therapy modification
Ketoconazole (Systemic): H2-Antagonists may decrease the serum concentration of Ketoconazole (Systemic). Management: Administer oral ketoconazole at least 2 hours prior to use of any H2-receptor antagonist. Monitor patients closely for signs of inadequate clinical response to ketoconazole. Consider therapy modification
Ledipasvir: H2-Antagonists may decrease the serum concentration of Ledipasvir. Consider therapy modification
Lomitapide: CYP3A4 Inhibitors (Weak) may increase the serum concentration of Lomitapide. Management: Patients on lomitapide 5 mg/day may continue that dose. Patients taking lomitapide 10 mg/day or more should decrease the lomitapide dose by half. The lomitapide dose may then be titrated up to a max adult dose of 30 mg/day. Consider therapy modification
Lumacaftor: May decrease the serum concentration of P-glycoprotein/ABCB1 Substrates. Lumacaftor may increase the serum concentration of P-glycoprotein/ABCB1 Substrates. Monitor therapy
Mebendazole: Cimetidine may increase the serum concentration of Mebendazole. Monitor therapy
Meperidine: Cimetidine may increase the serum concentration of Meperidine. Monitor therapy
Mesalamine: H2-Antagonists may diminish the therapeutic effect of Mesalamine. Histamine H2-Antagonist-mediated increases in gastrointestinal pH may cause the premature release of mesalamine from specific sustained-release mesalamine products. Management: Consider avoiding concurrent administration of high-dose histamine H2-receptor antagonists with sustained-release mesalamine products. Consider therapy modification
MetFORMIN: Cimetidine may increase the serum concentration of MetFORMIN. Consider therapy modification
Methylphenidate: H2-Antagonists may increase the absorption of Methylphenidate. Specifically, H2-antagonists may interfere with the normal release of drug from the extended-release capsules (Ritalin LA brand), which could result in both increased absorption (early) and decreased delayed absorption. Monitor therapy
Moclobemide: Cimetidine may decrease the metabolism of Moclobemide. Management: Consider using alternative agents to lower gastric pH in order to avoid this interaction. If combined, a moclobemide dose reduction of 50% is recommended and patients should be monitored for increased moclobemide effects/toxicities. Consider therapy modification
Multivitamins/Minerals (with ADEK, Folate, Iron): H2-Antagonists may decrease the serum concentration of Multivitamins/Minerals (with ADEK, Folate, Iron). Specifically, the absorption of iron may be impaired by H2-antagonists. Monitor therapy
Nelfinavir: H2-Antagonists may decrease the serum concentration of Nelfinavir. Concentrations of the active M8 metabolite may also be reduced. Monitor therapy
Nicotine: Cimetidine may increase the serum concentration of Nicotine. Monitor therapy
Nilotinib: H2-Antagonists may decrease the serum concentration of Nilotinib. Management: The nilotinib dose should be given 10 hours after or 2 hours before the H2 receptor antagonist in order to minimize the risk of a significant interaction. Consider therapy modification
PAZOPanib: H2-Antagonists may decrease the serum concentration of PAZOPanib. Management: Avoid the use of histamine H2-antagonists in combination with pazopanib. Strategies to minimize the expected interaction between these agents (eg, dose separation) have not been investigated. Avoid combination
Pentoxifylline: Cimetidine may increase the serum concentration of Pentoxifylline. Monitor therapy
Perhexiline: CYP2D6 Inhibitors (Weak) may increase the serum concentration of Perhexiline. Monitor therapy
P-glycoprotein/ABCB1 Inducers: May decrease the serum concentration of P-glycoprotein/ABCB1 Substrates. P-glycoprotein inducers may also further limit the distribution of p-glycoprotein substrates to specific cells/tissues/organs where p-glycoprotein is present in large amounts (e.g., brain, T-lymphocytes, testes, etc.). Monitor therapy
P-glycoprotein/ABCB1 Inhibitors: May increase the serum concentration of P-glycoprotein/ABCB1 Substrates. P-glycoprotein inhibitors may also enhance the distribution of p-glycoprotein substrates to specific cells/tissues/organs where p-glycoprotein is present in large amounts (e.g., brain, T-lymphocytes, testes, etc.). Monitor therapy
Pilsicainide: Cimetidine may increase the serum concentration of Pilsicainide. Monitor therapy
Pimozide: CYP3A4 Inhibitors (Weak) may increase the serum concentration of Pimozide. Avoid combination
Posaconazole: H2-Antagonists may decrease the serum concentration of Posaconazole. Management: Avoid concurrent use of oral suspension with H2-antagonists whenever possible. Monitor patients closely for decreased antifungal effects if this combination is used. Delayed-release posaconazole tablets may be less likely to interact. Consider therapy modification
Pramipexole: Cimetidine may increase the serum concentration of Pramipexole. Monitor therapy
Praziquantel: Cimetidine may increase the serum concentration of Praziquantel. Monitor therapy
Procainamide: Cimetidine may increase the serum concentration of Procainamide. Management: Consider an alternative H2-receptor antagonist in patients taking procainamide. If combined, monitor for increased therapeutic effects/toxicity of procainamide. Consider therapy modification
Propafenone: Cimetidine may increase the serum concentration of Propafenone. Monitor therapy
QuiNIDine: Cimetidine may increase the serum concentration of QuiNIDine. Management: Consider alternatives to cimetidine. If the combination cannot be avoided, monitor for increased quinidine concentrations/toxicity with cimetidine initiation/dose increase, or decreased concentrations/effects with cimetidine discontinuation/dose decrease. Consider therapy modification
QuiNINE: Cimetidine may increase the serum concentration of QuiNINE. Consider therapy modification
Ranolazine: May increase the serum concentration of P-glycoprotein/ABCB1 Substrates. Monitor therapy
Rilpivirine: H2-Antagonists may decrease the serum concentration of Rilpivirine. Management: Administer histamine H2 receptor antagonists at least 12 hours before or 4 hours after rilpivirine. Consider therapy modification
Risedronate: H2-Antagonists may increase the serum concentration of Risedronate. This applies specifically to delayed-release risedronate. Avoid combination
Roflumilast: Cimetidine may increase serum concentrations of the active metabolite(s) of Roflumilast. Cimetidine may increase the serum concentration of Roflumilast. Monitor therapy
Saquinavir: H2-Antagonists may increase the serum concentration of Saquinavir. Monitor therapy
Selective Serotonin Reuptake Inhibitors: Cimetidine may decrease the metabolism of Selective Serotonin Reuptake Inhibitors. Consider therapy modification
Sulfonylureas: Cimetidine may increase the serum concentration of Sulfonylureas. Monitor therapy
Tamsulosin: Cimetidine may increase the serum concentration of Tamsulosin. Monitor therapy
Tegafur: Cimetidine may increase serum concentrations of the active metabolite(s) of Tegafur. Specifically, concentrations of fluorouracil may be increased. Monitor therapy
Teriflunomide: May increase the serum concentration of OAT3 Substrates. Monitor therapy
Theophylline Derivatives: Cimetidine may decrease the metabolism of Theophylline Derivatives. Exceptions: Dyphylline. Consider therapy modification
TiZANidine: CYP1A2 Inhibitors (Weak) may increase the serum concentration of TiZANidine. Management: Avoid these combinations when possible. If combined use cannot be avoided, initiate tizanidine at an adult dose of 2 mg and increase in 2-4 mg increments based on patient response. Monitor for increased effects of tizanidine, including adverse reactions. Consider therapy modification
Tricyclic Antidepressants: Cimetidine may decrease the metabolism of Tricyclic Antidepressants. Monitor therapy
Varenicline: H2-Antagonists may increase the serum concentration of Varenicline. Management: Monitor for increased varenicline adverse effects with concomitant use of cimetidine or other H2-antagonists, particularly in patients with severe renal impairment. International product labeling recommendations vary. Consult appropriate labeling. Monitor therapy
Velpatasvir: H2-Antagonists may decrease the serum concentration of Velpatasvir. Monitor therapy
Vitamin K Antagonists (eg, warfarin): Cimetidine may enhance the anticoagulant effect of Vitamin K Antagonists. Consider therapy modification
Zaleplon: Cimetidine may decrease the metabolism of Zaleplon. Consider therapy modification
ZOLMitriptan: Cimetidine may increase the serum concentration of ZOLMitriptan. Monitor therapy
CBC, gastric pH; monitor renal function to correct dose; occult blood with GI bleeding; signs of confusion.
1% to 10%:
Central nervous system: Headache (2% to 4%), dizziness (1%), drowsiness (1%), agitation
Endocrine & metabolic: Gynecomastia (<1% to 4%)
Gastrointestinal: Diarrhea (1%)
Frequency not defined:
Cardiovascular: Atrioventricular block, bradycardia, hypotension, tachycardia, vasculitis
Central nervous system: Confusion, decreased sexual activity
Dermatologic: Alopecia, erythema multiforme, exfoliative dermatitis, skin rash, Stevens-Johnson syndrome, toxic epidermal necrolysis
Gastrointestinal: Nausea, pancreatitis, vomiting
Genitourinary: Breast swelling
Hematologic & oncologic: Agranulocytosis, aplastic anemia, hemolytic anemia (immune-based), neutropenia, pancytopenia, thrombocytopenia
Hepatic: Hepatic fibrosis (case report), increased serum ALT, increased serum AST
Hypersensitivity: Anaphylaxis
Neuromuscular & skeletal: Arthralgia, myalgia, polymyositis
Renal: Increased serum creatinine, interstitial nephritis
Respiratory: Pneumonia (causal relationship not established)
Miscellaneous: Fever
Drug accumulation may occur in patients with severe renal failure.
Concerns related to adverse effects:
- Confusion: Rare cases of reversible confusion have been associated with cimetidine; usually elderly or severely ill patients, or in patients with renal or hepatic impairment.
- Vitamin B12 deficiency: Prolonged treatment ( ≥2 years) may lead to vitamin B12 malabsorption and subsequent vitamin B12 deficiency. The magnitude of the deficiency is dose-related and the association is stronger in females and those younger in age (<30 years); prevalence is decreased after discontinuation of therapy (Lam 2013).
Disease-related concerns:
- Gastric malignancy: Relief of symptoms does not preclude the presence of a gastric malignancy.
- Hepatic impairment: Use with caution in patients with hepatic impairment.
- Renal impairment: Use with caution in patients with renal impairment; dosage adjustment recommended.
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: Use caution in this age group due to risk of confusion and other CNS effects.
- Immunocompromised patients: May have increased risk of hyperinfection of strongyloidiasis.
- Pediatric: Use of gastric acid inhibitors, including proton pump inhibitors and H2 blockers, has been associated with an increased risk for development of acute gastroenteritis and community-acquired pneumonia in pediatric patients (Canani 2006).
Other warnings/precautions:
- OTC labeling: When used for self-medication (OTC), notify health care provider before use if any of the following are present: Frequent chest pain; frequent wheezing particularly with heartburn; nausea/vomiting; unexplained weight loss; stomach pain; heartburn >3 months; heartburn with light-headedness, sweating, or dizziness; chest pain or shoulder pain with shortness of breath; sweating or pain that spreads to arms, neck, or shoulders; light-headedness. Stop use and notify health care provider if heartburn continues or worsens, stomach pain continues, or if use is required >14 days.
B
Adverse events have not been observed in animal reproduction studies. Cimetidine crosses the placenta (Howe 1981). Histamine H2 antagonists have been evaluated for the treatment of gastroesophageal reflux disease (GERD), as well as gastric and duodenal ulcers during pregnancy (Cappell 2003; Richter 2003). Histamine H2 antagonists may be used for aspiration prophylaxis prior to cesarean delivery (ASA 2007).
Competitive inhibition of histamine at H2 receptors of the gastric parietal cells resulting in reduced gastric acid secretion, gastric volume and hydrogen ion concentration reduced
Rapid
1 to 1.5 L/kg (Somogyi 1983)
Partially hepatic, forms metabolites (Somogyi 1983)
Primarily urine (48% as unchanged drug); feces (2%) (Somogyi 1983)
1 hour
Serum: Oral: 0.75 to 1.5 hours
80% reduction in gastric acid secretion for 4 to 5 hours after 300 mg dose
Neonates: 3.6 hours; Children: 1.4 hours; Adults: ~2 hours
20% (Somogyi 1983)
- 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?)
- Have patient report immediately to prescriber signs of liver problems (dark urine, feeling tired, lack of appetite, nausea, abdominal pain, light-colored stools, vomiting, or yellow skin or eyes), signs of pancreatitis (severe abdominal pain, severe back pain, severe nausea, or vomiting), urinary retention, change in amount of urine passed, tachycardia, bradycardia, arrhythmia, confusion, mood changes, hallucinations, enlarged breasts (males), or sexual dysfunction (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.