Pronunciation:

(sye MET i deen)

U.S. Brand Names:

Generic Available:

Canadian Brand Names:

Use:

Use - Unlabeled/Investigational:

Pregnancy Risk Factor:

Lactation:

Contraindications:

Warnings/Precautions:

Adverse Reactions:

1% to 10%:

Central nervous system: Dizziness, agitation, headache, drowsiness

Gastrointestinal: Diarrhea, nausea, vomiting

<1%: Bradycardia, hypotension, tachycardia, confusion, fever, rash, gynecomastia, edema of the breasts, decreased sexual ability, neutropenia, agranulocytosis, thrombocytopenia, increased AST/ALT, myalgia, elevated creatinine

Overdosage/Toxicology:

Drug Interactions:

Note: There are many potential interactions. Listed are the most significant ones.

Alfentanil; Increased serum concentration; monitor for toxicity.

Amiodarone's serum concentration is increased; avoid concurrent use.

Benzodiazepine's (except lorazepam, oxazepam, temazepam) serum concentration is increased; consider alternative H2 antagonist or monitor for benzodiazepine toxicity.

Beta-blockers (except atenolol, betaxolol, bisoprolol, nadolol, penbutolol) effects may be increased; use a renally-eliminated beta-blocker or alternative H2 antagonist.

Calcium channel blockers serum concentration is increased; monitor for toxicity.

Carbamazepine's plasma concentrations may increase transiently (1 week). Monitor for carbamazepine toxicity or use an alternative H2 antagonist.

Carmustine's myelotoxicity is increased; avoid concurrent use.

Cefpodoxime's and cefuroxime's oral absorption may be reduced by increased pH; consider alternative antibiotic.

Cisapride's bioavailability is increased; avoid concurrent use.

Citalopram's serum concentration is increased; use an alternative H2 antagonist or adjust citalopram's dose.

Cyclosporine's serum concentration may increase; monitor cyclosporine levels.

CYP1A2 substrates: Cimetidine may increase the levels/effects of CYP1A2 substrates. Example substrates include aminophylline, fluvoxamine, mexiletine, mirtazapine, ropinirole, theophylline, and trifluoperazine.

CYP2C19 substrates: Cimetidine may increase the levels/effects of CYP2C19 substrates. Example substrates include citalopram, diazepam, methsuximide, phenytoin, propranolol, and sertraline.

CYP2D6 substrates: Cimetidine may increase the levels/effects of CYP2D6 substrates. Example substrates include amphetamines, selected beta-blockers, dextromethorphan, fluoxetine, lidocaine, mirtazapine, nefazodone, paroxetine, risperidone, ritonavir, thioridazine, tricyclic antidepressants, and venlafaxine.

CYP2D6 prodrug substrates: Cimetidine may decrease the levels/effects of CYP2D6 prodrug substrates. Example prodrug substrates include codeine, hydrocodone, oxycodone, and tramadol.

CYP3A4 substrates: Cimetidine may increase the levels/effects of CYP3A4 substrates. Example substrates include benzodiazepines, calcium channel blockers, cyclosporine, mirtazapine, nateglinide, nefazodone, sildenafil (and other PDE-5 inhibitors), tacrolimus, and venlafaxine. Selected benzodiazepines (midazolam and triazolam), cisapride, ergot alkaloids, selected HMG-CoA reductase inhibitors (lovastatin and simvastatin), and pimozide are generally contraindicated with strong CYP3A4 inhibitors.

Delavirdine's absorption is decreased; avoid concurrent use with H2 antagonists.

Flecainide's serum concentration is increased, especially in patients with renal failure.

Ketoconazole, fluconazole, itraconazole (especially capsule): Decreased serum concentration; avoid concurrent use with H2 antagonists.

Lidocaine's serum concentration is increased; use alternative H2 antagonist.

Melphalan's serum concentration may be decreased; monitor for reduced efficacy.

Meperidine: Increased serum concentration; monitor for toxicity.

Moricizine's serum concentration is increased; monitor for toxicity.

Paroxetine's serum concentration is increased.

Phenytoin toxicity; avoid concurrent use.

Propafenone's serum concentration is increased; monitor for toxicity.

Quinolones: Renal elimination of quinolone antibiotics may be decreased.

Tacrine's plasma concentration is increased; consider alternative H2 antagonist.

TCAs serum concentration is increased; consider alternative H2 antagonist or monitor for TCAs toxicity.

Theophylline's serum concentration is increased; consider alternative H2 antagonist.

Warfarin's INR is increased; cimetidine's effect is dose-related. Use an alternative H2 antagonist if possible or monitor INR closely and adjust warfarin dose as needed.

Ethanol/Nutrition/Herb Interactions:

Ethanol: Avoid ethanol (may enhance gastric mucosal irritation).

Food: Cimetidine may increase serum caffeine levels if taken with caffeine. Cimetidine peak serum levels may be decreased if taken with food.

Herb/Nutraceutical: St John's wort may decrease cimetidine levels.

Stability:

Intact vials of cimetidine should be stored at room temperature and protected from light; cimetidine may precipitate from solution upon exposure to cold but can be redissolved by warming without degradation

Stability at room temperature:

Prepared bags: 7 days

Premixed bags: Manufacturer expiration dating and out of overwrap stability: 15 days

Stable in parenteral nutrition solutions for up to 7 days when protected from light

Physically incompatible with barbiturates, amphotericin B, and cephalosporins

Compatibility:

Y-site administration: Compatible: Acyclovir, amifostine, aminophylline, atracurium, aztreonam, cisatracurium, cisplatin, cladribine, clarithromycin, cyclophosphamide, cytarabine, diltiazem, docetaxel, doxorubicin, doxorubicin liposome, enalaprilat, esmolol, etoposide, filgrastim, fluconazole, fludarabine, foscarnet, gatifloxacin, gemcitabine, granisetron, haloperidol, heparin, hetastarch, idarubicin, inamrinone, labetalol, levofloxacin, linezolid, melphalan, meropenem, methotrexate, midazolam, milrinone, ondansetron, paclitaxel, pancuronium, piperacillin/tazobactam, propofol, remifentanil, sargramostim, tacrolimus, teniposide, theophylline, thiotepa, tolazoline, topotecan, vecuronium, vinorelbine, zidovudine. Incompatible: Allopurinol, amphotericin B cholesteryl sulfate complex, amsacrine, cefepime, indomethacin, warfarin. Variable (consult detailed reference): TPN

Compatibility in syringe: Compatible: Atropine, butorphanol, diatrizoate meglumine and diatrizoate sodium, diatrizoate sodium, diazepam, diphenhydramine, doxapram, droperidol, fentanyl, glycopyrrolate, heparin, hydromorphone, hydroxyzine, iohexol, iopamidol, iothalamate meglumine, lorazepam, meperidine, midazolam, morphine, nafcillin, nalbuphine, penicillin G sodium, pentazocine, perphenazine, prochlorperazine edisylate, promazine, promethazine, scopolamine, sodium acetate, sodium chloride, sodium lactate. Incompatible: Atropine with pentobarbital, cefamandole, cefazolin, chlorpromazine, ioxaglate meglumine and ioxaglate sodium, pentobarbital, secobarbital

Compatibility when admixed: Compatible: Acetazolamide, amikacin, aminophylline, ampicillin, atracurium, cefoperazone, cefoxitin, ceftazidime, chlorothiazide, clindamycin, colistimethate, cryptenamine, dexamethasone sodium phosphate, digoxin, epinephrine, erythromycin lactobionate, ethacrynate sodium, floxacillin, flumazenil, furosemide, gentamicin, insulin (regular), isoproterenol, lidocaine, lincomycin, meropenem, metaraminol, methylprednisolone sodium succinate, metoclopramide, norepinephrine, penicillin G potassium, phytonadione, polymyxin B sulfate, potassium chloride, protamine, quinidine gluconate, sodium nitroprusside, tacrolimus, vancomycin, verapamil, vitamin B complex, vitamin B complex with C. Incompatible: Amphotericin B, barbiturates. Variable (consult detailed reference): Cefamandole, cefazolin

Mechanism of Action:

Pharmacodynamics/Kinetics:

Onset of action: 1 hour

Duration: 6 hours

Distribution: Crosses placenta; enters breast milk

Protein binding: 20%

Metabolism: Partially hepatic

Bioavailability: 60% to 70%

Half-life elimination: Neonates: 3.6 hours; Children: 1.4 hours; Adults: Normal renal function: 2 hours

Time to peak, serum: Oral: 1-2 hours

Excretion: Primarily urine (as unchanged drug); feces (some)

Dosage:

Children: Oral, I.M., I.V.: 20-40 mg/kg/day in divided doses every 6 hours

Children 12 years and Adults: Oral: Heartburn, acid indigestion, sour stomach (OTC labeling): 200 mg up to twice daily; may take 30 minutes prior to eating foods or beverages expected to cause heartburn or indigestion

Adults:

Short-term treatment of active ulcers:

Oral: 300 mg 4 times/day or 800 mg at bedtime or 400 mg twice daily for up to 8 weeks

I.M., I.V.: 300 mg every 6 hours or 37.5 mg/hour by continuous infusion; I.V. dosage should be adjusted to maintain an intragastric pH 5

Patients with an active bleed: Administer cimetidine as a continuous infusion (see above)

Duodenal ulcer prophylaxis: Oral: 400-800 mg at bedtime

Gastric hypersecretory conditions: Oral, I.M., I.V.: 300-600 mg every 6 hours; dosage not to exceed 2.4 g/day

Helicobacter pylori eradication (unlabeled use): 400 mg twice daily; requires combination therapy with antibiotics

Dosing adjustment/interval in renal impairment: Children and Adults:

Clcr 20-40 mL/minute: Administer every 8 hours or 75% of normal dose

Clcr 0-20 mL/minute: Administer every 12 hours or 50% of normal dose

Hemodialysis: Slightly dialyzable (5% to 20%)

Dosing adjustment/comments in hepatic impairment: Usual dose is safe in mild liver disease but use with caution and in reduced dosage in severe liver disease; increased risk of CNS toxicity in cirrhosis suggested by enhanced penetration of CNS

Administration:

Oral: Administer with meals so that the drug's peak effect occurs at the proper time (peak inhibition of gastric acid secretion occurs at 1 and 3 hours after dosing in fasting subjects and approximately 2 hours in nonfasting subjects; this correlates well with the time food is no longer in the stomach offering a buffering effect)

Injection: May be administered as a slow I.V. push or preferably as an I.V. intermittent or I.V. continuous infusion. Administer each 300 mg (or fraction thereof) over a minimum of 5 minutes when giving I.V. push. Give intermittent infusion over 15-30 minutes for each 300 mg dose. Intermittent infusions are administered over 15-30 minutes at a final concentration not to exceed 6 mg/mL; for patients with an active bleed, preferred method of administration is continuous infusion.

Monitoring Parameters:

Test Interactions:

Patient Education:

Anesthesia and Critical Care Concerns/Other Considerations:

Cardiovascular Considerations:

Dental Health: Effects on Dental Treatment:

Dental Health: Vasoconstrictor/Local Anesthetic Precautions:

Mental Health: Effects on Mental Status:

Mental Health: Effects on Psychiatric Treatment:

Dosage Forms:

Infusion, as hydrochloride [premixed in NS]: 300 mg (50 mL)

Injection, solution, as hydrochloride: 150 mg/mL (2 mL, 8 mL) [8 mL size contains benzyl alcohol]

Liquid, oral, as hydrochloride: 300 mg/5 mL (240 mL, 480 mL) [contains alcohol 2.8%; mint-peach flavor]

Tablet: 200 mg [OTC], 300 mg, 400 mg, 800 mg

Tagamet: 300 mg, 400 mg

Tagamet® HB 200: 200 mg

International Brand Names: