Cimetidine

Class: Histamine H2-Antagonists
VA Class: GA301
CAS Number: 51481-61-9
Brands: Tagamet

Introduction

Histamine H₂ receptor antagonist.^b

Uses for Cimetidine

Duodenal Ulcer

Short-term treatment of active duodenal ulcer (endoscopically or radiographically confirmed).^{a b}

Maintainence of healing and reduction in recurrence of duodenal ulcer.^{a b}

Pathologic GI Hypersecretory Conditions

Long-term treatment of Zollinger-Ellison syndrome, multiple endocrine adenomas, systemic mastocytosis.^{a b}

Gastric Ulcer

Short-term treatment of active benign gastric ulcer.^{a b}

Gastroesophageal Reflux (GERD)

Short-term treatment of erosive esophagitis (endoscopically diagnosed) in patients with GERD.¹¹⁸

Treatment of symptomatic GERD†.^{105 106 123 288}

Self-medication as initial therapy to achieve acid suppression, control symptoms, and prevent complications of less severe symptomatic GERD†.²⁸⁸

Upper GI Bleeding

Prevention of upper GI bleeding resulting from stress-related mucosal damage (erosive esophagitis, stress ulcers) in critically ill patients.^{118 142 143 144 145 146 147 152 153 154 155 156 157 161 162 163 164 165 166 170 171 172 173 174 175 176 177 179 188 191}

Treatment of upper GI bleeding† secondary to hepatic failure, esophagitis, duodenal or gastric ulcers when hemorrhage is not caused by major blood vessel erosion.^b

Heartburn (pyrosis), Acid Indigestion (hyperchlorhydria), or Sour Stomach

Short-term self-medication for relief of heartburn symptoms in adults and adolescents≥12 years of age.^c

Short-term self-medication for prevention of heartburn symptoms associated with acid indigestion (hyperchlorhydria) and sour stomach brought on by ingestion of certain foods and beverages in adults and children ≥12 years of age.^c

Allergic Conditions and Urticarias†^{124 125 126 127 128 129 130 131 132 133 134 135 136 137}

Cimetidine Dosage and Administration

Administration

Administer orally, IV, or IM.¹¹⁸

Administer by IM or slow IV injection, or by intermittent or continuous IV infusion in hospitalized patients with pathological GI hypersecretory conditions or intractable duodenal ulcer, or when oral therapy is not feasible.¹¹⁸

Oral Administration

Administer with or without food; administration with food may delay and slightly decrease absorption, but achieves maximum antisecretory effect when stomach is no longer protected by food buffering effect. Administer oral tablets with water.^b

Antacids may be given as necessary for pain relief, but not at the same time.^{a b}

For duodenal ulcer treatment, administration once daily at bedtime is the regimen of choice because of a high healing rate, maximal pain relief, decreased drug interaction potential, and maximal compliance.^{117 118 119}

For gastric ulcer treatment, administration once daily at bedtime is the regimen of choice because of convenience and decreased drug interaction potential.¹¹⁸

For gastroesophageal reflux, once-daily dosing is not considered appropriate.²⁸⁸

IM Administration

May be administered undiluted.^{a b}

Intermittent Direct IV Injection

Dilution

Dilute 300 mg to 20 mL with 0.9% sodium chloride injection or other compatible IV solution before direct IV injection (see Compatibility under Stability).¹¹⁸

Rate of Administration

Inject over ≥5 minutes.¹¹⁸

Intermittent IV infusion

Reconstitution

Reconstitute ADD-Vantage vials according to manufacturer’s directions.¹¹⁸

Dilution

Dilute 300 mg in at least 50 mL of 0.9% sodium chloride injection or 5% dextrose injection or other compatible IV solution (see Compatibility under Stability).¹¹⁸

No additional dilution required for commercially available infusion solution (300 mg cimetidine in 50 mL of 0.9% sodium chloride injection).^a

Rate of Administration

Over 15–20 minutes.¹¹⁸

Continuous IV Infusion

Dilution

Dilute 900 mg in 100–1000 mL of a compatible IV solution (see Compatibility under Stability).^{a b}

Rate of Administration

Over 24 hours.^{a b}

Adjust rate to individual patient requirements.^{a b}

Volume <250 mL: use controlled-infusion device (e.g., pump).^{a b}

Dosage

Dosage of cimetidine hydrochloride expressed in terms of cimetidine.¹¹⁸

Pediatric Patients

20–40 mg/kg daily in divided doses has been used in a limited number of children when potential benefits are thought to outweigh the possible risks.¹¹⁸

Heartburn, Acid Indigestion, or Sour Stomach

Heartburn Relief (Self-medication)

Oral

Adolescents ≥12 years of age: 200 mg once or twice daily, or as directed by a clinician.²⁶⁸

Prevention of Heartburn (Self-medication)

Oral

Adolescents ≥12 years of age: 200 mg once or twice daily or as directed by a clinician; administer immediately (or up to 30 minutes) before ingestion of causative food or beverage.^c

Adults

General Parenteral Dosage

Parenteral dosage regimens for GERD have not been established.^a

General parenteral dosage (in hospitalized patients with pathologic hypersecretory conditions or intractable ulcer, or for short-term use when oral therapy is not feasible):^a

IM

300 mg every 6–8 hours.¹¹⁸

Intermittent Direct IV Injection

300 mg every 6–8 hours.¹¹⁸

300 mg more frequently if increased daily dosage is necessary (i.e., single doses not >300 mg), up to 2400 mg daily.¹¹⁸

Intermittent IV Infusion

300 mg every 6–8 hours.¹¹⁸

300 mg more frequently if increased daily dosage is necessary (i.e., single doses not >300 mg), up to 2400 mg daily.¹¹⁸

Continuous IV infusion

900 mg over 24 hours (37.5 mg/hour).^{a b} See Pathologic GI Hypersecretory Conditions under Dosage: Adults.

For more rapid increase in gastric pH, a loading dose of 150 mg may be given as an intermittent infusion before continuous infusion.^{a b}

Duodenal Ulcer

Treatment of Active Duodenal Ulcer

Oral

Dosage of choice: 800 mg once daily at bedtime.^{117 118 119}

Patients with ulcer >1 cm in diameter who are heavy smokers (i.e., ≥1 pack daily) when rapid healing (e.g., within 4 weeks) is considered important:¹¹⁸ 1.6 g daily at bedtime.^{117 118 119}

Administer for 4–6 weeks unless healing is confirmed earlier.^{117 118} If not healed or symptoms continue after 4 weeks, additional 2–4 weeks of full dosage therapy may be beneficial.¹¹⁸ More than 6–8 weeks at full dosage is rarely needed.¹¹⁸

Healing of active duodenal ulcers may occur in 2 weeks in some, and occurs within 4 weeks in most patients.^{117 118 119 120 121 122}

Other regimens (no apparent rationale for these other than familiarity of use) that have been used:^{117 118} 300 mg 4 times daily with meals and at bedtime; 200 mg 3 times daily and 400 mg at bedtime; 400 mg twice daily in the morning and at bedtime.^b

Maintenance of Healing of Duodenal Ulcer

Oral

400 mg daily at bedtime.¹¹⁸ Efficacy not increased by higher dosages or more frequent administration.^b

Pathologic GI Hypersecretory Conditions

Zollinger-Ellison Syndrome

Oral

300 mg 4 times daily with meals and at bedtime.¹¹⁸

Higher doses administered more frequently may be necessary;^{a b} adjust dosage according to response and tolerance but in general, do not exceed 2400 mg daily.^a

Continue as long as necessary.¹¹⁸

Continuous IV Infusion

Mean infused dose of 160 mg/hour (range: 40-600 mg/hour) in one study.^a

Gastric Ulcer

Oral

Preferred regimen: 800 mg once daily at bedtime.¹¹⁸

Alternative regimen: 300 mg 4 times daily, with meals and at bedtime.¹¹⁸

Monitor to ensure rapid progress to complete healing.^{a b}

Studies limited to 6 weeks, efficacy for >8 weeks not established.¹¹⁸

GERD

Once daily (at bedtime) not considered appropriate therapy.²⁸⁸

Treatment of Symptomatic GERD†

Oral

300 mg 4 times daily has been used.^{105 106 123}

Treatment of Erosive Esophagitis

Oral

800 mg twice daily or 400 mg 4 times daily (e.g., before meals and at bedtime) for up to 12 weeks.¹¹⁸

Upper GI Bleeding

Prevention of Upper GI Bleeding

Continuous IV Infusion

50 mg/hour; loading dose not required.¹¹⁸

Safety and efficacy of therapy beyond 7 days has not been established.¹¹⁸

Alternative dosage: Some clinicians recommend 300-mg IV loading dose over 5–20 minutes, then continuous IV infusion at 37.5–50 mg/hour; titrate with 25-mg/hour increments up to 100 mg/hour based on gastric pH (e.g., to maintain a pH of at least 3.5–4).^{118 143 144 173 174 176 188}

Intermittent IV doses may be less effective in preventing upper GI bleeding than continuous IV infusion.^{155 172 173 174 175 176 177 178 188 189 191}

Treatment of Upper GI Bleeding†

Oral

1–2 g daily in 4 divided doses has been used.^b

IV

1–2 g daily in 4 divided doses has been used.^b

Heartburn, Acid Indigestion, or Sour Stomach

Heartburn (Self-medication)

Oral

200 mg once or twice daily, or as directed by clinician.²⁶⁸

Maximum 400 mg in 24 hours, but not continuously for >2 weeks except under clinician supervision.^c

Prevention of Heartburn (Self-medication)

Oral

200 mg once or twice daily or as directed by a clinician; administer immediately (or up to 30 minutes) before ingestion of causative food or beverage.^c

Maximum 400 mg in 24 hours, but not continuously for >2 weeks except under clinician supervision.^c

Prescribing Limits

Pediatric Patients

Heartburn, Acid Indigestion, or Sour Stomach

Heartburn (Self-Medication)

Oral

Adolescents ≥12 years of age: Maximum 400 mg in 24 hours, but not continuously for >2 weeks except under clinician supervision.^c

Prevention of Heartburn (Self-medication)

Oral

Adolescents ≥12 years of age: Maximum 400 mg in 24 hours, but not continuously for >2 weeks except under clinician supervision.^c

Adults

General Parenteral Dosage

General parenteral dosage (hospitalized patients with pathologic hypersecretory conditions or intractable duodenal ulcer, or short-term use when oral therapy is not feasible):

Direct IV injection

Maximum 2.4 g daily.^a

Maximum 300 mg per dose.^a

Maximum concentration 300 mg/20 mL.^a

Maximum injection rate: 20 mL over not less than 5 minutes (4 mL per minute).^a

Intermittent IV Infusion

Maximum 2.4 g daily.^a

Maximum 300 mg per dose.^a

Maximum concentration 300 mg/50 mL.^a

Maximum infusion rate: 15–20 minutes.^a

GERD

Short-term Treatment of Erosive Esophagitis

Oral

Safety and efficacy beyond 12 weeks of administration have not been established.^a

Heartburn, Acid Indigestion, or Sour Stomach

Heartburn Relief (Self-medication)

Oral

Maximum 400 mg in 24 hours, but not continuously for >2 weeks except under clinician supervision.^c

Prevention of Heartburn (Self-medication)

Oral

Maximum 400 mg in 24 hours, but not continuously for >2 weeks except under clinician supervision.^c

Duodenal Ulcer

Intermittent Direct IV Injecton

Maximum 2.4 g daily.^a

Intermittent IV Infusion

Maximum 2.4 g daily.^a

Gastric Ulcer

Short-term treatment of Active Benign Gastric Ulcer

Oral

Safety and efficacy beyond 8 weeks have not been established.¹¹⁸

Intermittent Direct IV Injection

Maximum 2.4 g daily.^a

Intermittent IV Infusion

Maximum 2.4 g daily.^a

Pathologic GI Hypersecretory Conditions (e.g., Zollinger-Ellison Syndrome)

Oral

Maximum usually 2.4 g daily.¹¹⁸

Intermittent Direct IV Injection

Maximum 2.4 g daily.^a

Intermittent IV Infusion

Maximum 2.4 g daily.^a

Upper GI Bleeding

Prevention of Upper GI Bleeding

Continuous IV Infusion

Safety and efficacy beyond 7 days have not been established.^a

Special Populations

Renal Impairment

Severe (Cl_cr< 30 mL/minute)

Oral

300 mg every 12 hours.¹¹⁸

Accumulation may occur; use lowest frequency of dosing compatible with adequate response.¹¹⁸

Increase frequency to every 8 hours or more frequently (with caution) if required.¹¹⁸

Presence of hepatic impairment may require further dosage reduction.¹¹⁸

Direct IV Injection

300 mg every 12 hours.¹¹⁸

Accumulation may occur; use lowest frequency compatible with adequate response.¹¹⁸

Increase frequency to every 8 hours or more frequently (with caution) if required¹¹⁸

Presence of hepatic impairment may require further dosage reduction.¹¹⁸

Continuous IV Infusion

Prevention of Upper GI Bleeding: One-half recommended dosage (i.e., 25 mg/hour).¹¹⁸

Hemodialysis

Decreases blood levels; administer at the end of hemodialysis and every 12 hours during interdialysis.^b

Hepatic Impairment

May require further dosage reduction in the presence of severe renal impairment.¹¹⁸

Cautions for Cimetidine

Contraindications

• 
  

  Known hypersensitivity to cimetidine or any ingredient in the formulation.¹¹⁸

  
  

Warnings/Precautions

General Precautions

Cardiovascular Effects

Rapid IV administration associated rarely with hypotension, cardiac arrhythmias; avoid.^{a b}

Gastric Malignancy

Response to cimetidine does not preclude presence of gastric malignancy.¹¹⁸

CNS Effects

Reversible confusional states reported, especially in geriatric (i.e., ≥50 years) and severely ill (e.g., hepatic or renal disease, organic brain syndrome) patients.^{118 b} Usually occurs within 2–3 days after initiating cimetidine and resolves within 3–4 days after discontinuance.^{118 b}

Respiratory Effects

Administration of H₂-receptor antagonists has been associated with an increased risk for developing certain infections (e.g., community-acquired pneumonia).^{302 303}

Specific Populations

Pregnancy

Category B.^a

Pregnant women should consult a clinician before using for self-medication.²⁶⁸

Lactation

Distributed into milk.¹¹⁸ Generally, do not nurse during therapy with cimetidine.¹¹⁸

Nursing women should consult a clinician before using for self-medication.²⁶⁸

Pediatric Use

Safety and efficacy not established in children <16 years of age; do not use unless potential benefits outweigh risks.¹¹⁸

Safety and efficacy for self-medication not established in children <12 years of age; do not use unless directed by a clinician.^c

Renal Impairment

Dosage adjustments necessary in patients with severe renal impairment.¹¹⁸ (See Renal Impairment under Dosage and Administration.)

Hepatic Impairment

Further dosage adjustments may be necessary in presence of severe renal impairment.¹¹⁸ (See Hepatic Impairment under Dosage and Administration.)

Immunocompromised Patients

Increased possibility of Strongyloides stercoralis hyperinfection with decreased gastric acidity.^{118 269 270}

Common Adverse Effects

Headache,^{118 144} dizziness, somnolence, diarrhea.¹¹⁸

With ≥1 month of therapy: gynecomastia.^{118 b}

With IM therapy: transient pain at injection site.¹¹⁸

Interactions for Cimetidine

Inhibits hepatic microsomal enzyme systems, decreases hepatic metabolism of some drugs.¹¹⁸ If necessary, adjust dosage of hepatically metabolized drugs when cimetidine therapy is initiated or discontinued.^b

Specific Drugs

Drug	Interaction	Comments
Alcohol	Possible increased blood alcohol concentrations,256 257 258 259 260 261 263 264 265 psychomotor impairment256 257 258 259 260 261 267	Potential for psychomotor impairment controversial, 256 257 258 259 260 261 267 but use caution during performance of hazardous tasks requiring mental alertness, physical coordination257 258 261
Antacidsb	Decreased cimetidine absorptionb	Administer 1 hour before or after cimetidine in the fasting state, or 1 hour after cimetidine is taken with food.a b
Benzodiazepines118	Potential for delayed elimination, increased blood concentrations of certain benzodiazepines (e.g., diazepam, chlordiazepoxide, triazolam)118	Adjust dosage if needed b
Calcium-channel blockers (e.g., nifedipine)a	Potential for delayed elimination, increased blood concentrations of nifedipine118	Adjust dosage if needed b
Ketoconazole118	Absorption of ketoconazole may be affected by altered gastric pH118	Administer ≥2 hours before cimetidine118
Lidocaine118	Potential for delayed elimination, increased blood concentrations of lidocaine118	Adverse effects reported, adjust dosage if needed b
Metronidazole118	Potential for delayed elimination, increased blood concentrations of metronidazole118	Adjust dosage if neededb
Myelosuppressive drugs (e.g., alkylating agents [e.g., carmustine], antimetabolites) and/or therapies (radiation)b	May potentiate myelosuppressionb
Phenytoin118	Potential for delayed elimination, increased blood concentrations of phenytoin118	Adverse effects reported, adjust dosage if needed b
Propranolol118	Potential for delayed elimination, increased blood concentrations of propranolol118	Adjust dosage if needed b
Theophylline118	Potential for delayed elimination, increased blood concentrations of theophylline118	Adverse effects reported, adjust dosage if needed b
Triamterene108	Potential for delayed elimination, increased blood concentrations of triamterene118	Consider potential of clinically important interaction108
Tricyclic Antidepressants118	Potential for delayed elimination, increased blood concentrations of certain tricyclic antidepressants118	Adjust dosage if neededb
Warfarin118	Potential for delayed elimination, increased blood concentrations of warfarin118	Monitor PT, adjust dosage if neededb

Cimetidine Pharmacokinetics

Absorption

Bioavailability

Oral: 60–70%.^b

Onset

≥70% decrease in basal acid secretion within 45 minutes after single 300- or 400-mg IV dose in healthy males.¹⁰⁰

Duration

Dosage Regimen	Effect On Acid Secretion	Comments
Oral: 800 mg at bedtime in duodenal ulcer patients118	Mean hourly nocturnal secretion decreased by 85% over 8 hours.118	No effect on daytime acid secretion118
Oral: 1600 mg at bedtime in duodenal ulcer patients 118	Mean hourly nocturnal secretion decreased by 100% over 8 hours, 35% decrease for additional 5 hours.118	Moderate (<60%) 24-hour suppression118
Oral: 400 mg twice daily in duodenal ulcer pateints118	Nocturnal secretion decreased by 47–83% over 6–8 hours 118	Moderate (<60%) 24-hour suppression118
Oral: 300 mg 4 times daily in duodenal ulcer patients118	Nocturnal secretion decreased by 54% over 9 hours118	Moderate (<60%) 24-hour suppression118
Oral: Single 300-mg dose within 1 hour after meal in duodenal ulcer patientsa	Food-stimulated secretion decreased by 50% for 1 hour, then 75% for 2 hours.a
Oral: 300-mg dose at breakfast in duodenal ulcer patientsa	Continued suppression for 4 hours, with partial suppression after luncha	Effect enhanced and maintained by additional 300-mg dose with luncha
Oral: 300-mg dose with foodb	Mean gastric pH 3.5–4 at 1 hour, 5.5–6.1 at 4 hoursb
Oral: Single dose 300 mg with fooda	Mean gastric pH: 3.5, 3.1, 3.8, 6.1 at hour 1, 2, 3, 4, respectivelya	Placebo mean gastric pH: 2.6, 1.6, 1.9, 2.2 at hour 1, 2, 3, 4, respectivelya
Oral: 300–400 mg in fasting state in duodenal ulcer patientsb	Anacidity for up to 8 hoursb
Oral: 300 mg in duodenal ulcer patientsb	Basal gastric acid output decreased by 90% for 4 hoursb	Meal-stimulated acid secretion by 66% for 3 hoursb
IV continuous infusion: mean dosage of 160 mg/hour (range:40-600 mg/hour) in pathologic hypersecretory conditionsb	Maintained secretion at ≤10 mEq/hourb
IV continuous infusion (37.5 mg/hour or 900 mg daily) in patients with active or healed duodenal or gastric ulcerb	Maintained gastric pH at >4 for >50% of the time at steady-state.b
Intermittent injection: (300 mg every 6 hours or 1200 mg daily) in patients with active or healed duodenal or gastric ulcerb	Maintained gastric pH at >4 for >50% of the time at steady-state.b
IV: Single 300- or 400-mg dose in healthy males	≥70% decrease in basal acid secretion maintained for 4–4.5 hours100

Food

Delays, slightly decreases absorption.^b However, administration with meals achieves maximum blood concentrations and antisecretory effect when stomach is no longer protected by food buffering effect.^b

Distribution

Extent

Widely distributed throughout the body.^b

Distributed into human milk.^b

Crosses the placenta in animals.^b

Plasma Protein Binding

15–20%.^b

Elimination

Metabolism

Metabolized to sulfoxide (major metabolite) and 5-hydroxymethyl derivatives in liver.^{a b} More extensively metabolized after oral than parenteral administration.^a

Elimination Route

Excreted principally in urine.^{a b} Single oral dose: 48% (unchanged) excreted in urine over 24 hours.^a IV or IM: about 75% (unchanged) excreted in urine within 24 hours.^a Single IV dose of radiolabeled cimetidine: 80–90% (50–73% unchanged, remainder as metabolites) excreted in urine over 24 hours.^b About 10% excreted in feces.^b

Half-life

2 hours.^a

After IV administration in children 4.1–15 years of age: Apparent biphasic decline of plasma cimetidine and cimetidine sulfoxide concentrations with half-lives of 1.4 and 2.6 hours, respectively.¹⁰²

Special Populations

2.9 hours in patients with Cl_cr 20–50 mL/minute.^b 3.7 hours in patients with Cl_cr <20 mL/minute.^b 5 hours in anephric patients.^b

Stability

Storage

Oral

Liquid and Tablets

Tight, light-resistant containers at 15–30°C.^b

Parenteral

Injection

15–30°C.^b Protect from light.^b Do not refrigerate.^b Stable in most IV solutions for at least 3 days at room temperature in concentrations of 1.2–5 mg/mL,^b but use within 48 hours when diluted as directed.^{118 b}

Injection for IV infusion only

15–30°C.^b Protect from excessive heat; brief exposure up to 40°C does not adversely affect stability.^b Stable through the labeled expiration date when stored as recommended.¹¹⁸

Compatibility

For information on systemic interactions resulting from concomitant use, see Interactions.

Parenteral

Solution Compatibility^HID

Compatible
Amino acids 3.5, 5.5, or 8.5% with electrolytes
Amino acids 5.5 or 8.5%
Dextrose 5% with Ascor-B-Sol
Dextrose 5% and Electrolyte #48
Dextrose 5% and Electrolyte #75
Dextrose 5% in Ringer’s injection, lactated
Dextrose 5% in sodium chloride 0.2, 0.45, or 0.9%
Dextrose 10% in sodium chloride 0.9%
Dextrose 5% in water
Dextrose 10% in water
Dextrose 5% in water with vitamins
Fructose 5% and Electrolyte #48
Fructose 5% and Electrolyte #75
Invert sugar 5% in water
Invert sugar 10% in water
Ionosol B in dextrose 5% in water
Ionosol MB in dextrose 5% in water
Ionosol T in dextrose 5% in water
Mannitol 10% in water
Normosol M, 900 cal
Normosol M in dextrose 5% in water
Normosol M and Surbex T in dextrose 5% in water
Normosol R
Normosol R, pH 7.4
Normosol R in dextrose 5% in water
Plasma-Lyte 56 in dextrose 5% in water
Plasma-Lyte M in dextrose 5% in water
Ringer’s injection
Ringer’s injection, lactated
Sodium bicarbonate 5%
Sodium chloride 0.9%

Drug Compatibility

Admixture CompatibilityHID

Compatible
Acetazolamide sodium
Amikacin sulfate
Aminophylline
Atracurium besylate
Cefoxitin sodium
Chlorothiazide sodium
Ciprofloxacin
Clindamycin phosphate
Colistimethate sodium
Dexamethasone sodium phosphate
Digoxin
Epinephrine HCl
Erythromycin lactobionate
Ethacrynate sodium
Flumazenil
Furosemide
Gentamicin sulfate
Insulin, regular
Isoproterenol HCl
Lidocaine HCl
Lincomycin HCl
Meropenem
Metaraminol bitartrate
Methylprednisolone sodium succinate
Midazolam HCl
Norepinephrine bitartrate
Penicillin G potassium
Phytonadione
Polymyxin B sulfate
Potassium chloride
Protamine sulfate
Quinidine gluconate
Sodium nitroprusside
Tacrolimus
Vancomycin HCl
Verapamil HCl
Vitamin B complex
Vitamin B complex with C
Incompatible
Amphotericin B
Variable
Ampicillin sodium
Cefazolin sodium
Metoclopramide HCl

Y-Site CompatibilityHID

Compatible
Acyclovir sodium
Amifostine
Aminophylline
Anakinra
Anidulafungin
Atracurium besylate
Aztreonam
Bivalirudin
Cisplatin
Cladribine
Clarithromycin
Cyclophosphamide
Cytarabine
Dexmedetomidine HCl
Diltiazem HCl
Docetaxel
Doxorubicin HCl
Doxorubicin HCl liposome injection
Enalaprilat
Esmolol HCl
Etoposide phosphate
Fenoldopam mesylate
Filgrastim
Fluconazole
Fludarabine phosphate
Foscarnet sodium
Gallium nitrate
Gemcitabine HCl
Granisetron HCl
Haloperidol lactate
Heparin sodium
Hetastarch in lactated electrolyte injection (Hextend)
Hetastarch in sodium chloride 0.9%
Idarubicin HCl
Inamrinone lactate
Labetalol HCl
Levofloxacin
Linezolid
Melphalan HCl
Meropenem
Methotrexate sodium
Midazolam HCl
Milrinone lactate
Nicardipine HCl
Ondansetron HCl
Oxaliplatin
Paclitaxel
Pancuronium bromide
Pemetrexed disodium
Piperacillin sodium–tazobactam sodium
Propofol
Remifentanil HCl
Sargramostim
Tacrolimus
Teniposide
Theophylline
Thiotepa
Topotecan HCl
Vecuronium bromide
Vinorelbine tartrate
Zidovudine
Incompatible
Allopurinol sodium
Amphotericin B cholesteryl sulfate complex
Amsacrine
Cefepime HCl
Indomethacin sodium trihydrate
Lansoprazole
Warfarin sodium

ActionsActions

• 
  

  Inhibits basal and stimulated gastric acid secretion.^b

  
  


• 
  

  Competitively inhibits histamine at parietal cell H₂ receptors.^b

  
  


• 
  

  Weak antiandrogenic effect.^b

  
  

Advice to Patients

• 
  

  Importance of patients informing clinician of existing or contemplated concomitant therapy, including prescription and OTC drugs.²⁸⁹

  
  


• 
  

  Importance of taking antacids on an empty stomach 1 hour before or 1 hour after oral administration of cimetidine, or 1 hour after the drug is taken with food,^b but not at same time as oral cimetidine.^{a b}

  
  


• 
  

  Importance of women informing clinician if they are or plan to become pregnant or plan to breast-feed.²⁸⁹

  
  


• 
  

  Before self-medication, importance of consulting clinician if taking warfarin, theophylline, or phenytoin.²⁶⁸

  
  


• 
  

  Importance of following dosage instructions when cimetidine is administered for self-medication, unless otherwise directed by a clinician.^c

  
  


• 
  

  Importance of promptly informing clinician of persistent abdominal pain or difficulty swallowing.²⁶⁸

  
  


• 
  

  Importance of informing patients of other important precautionary information. (See Cautions.)

  
  

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Cimetidine

Routes	Dosage Forms	Strengths	Brand Names	Manufacturer
Oral	Solution	300 mg/mL*	Cimetidine Hydrochloride Oral Solution	Actavis, Duramed, Endo, Hi-Tech, Morton Grove, Pharmaceutical Associates, Teva
			Tagamet (with parabens, povidone, and propylene glycol)	GlaxoSmithKline
	Tablets, film-coated	200 mg*	Tagamet HB 200	GlaxoSmithKline
			Tagamet HB (with povidone)	GlaxoSmithKline
		300 mg*	Tagamet (with povidone and propylene glycol)	GlaxoSmithKline
		400 mg*	Tagamet Tiltab (with povidone and propylene glycol)	GlaxoSmithKline
		800 mg*	Tagamet Tiltab (with povidone and propylene glycol; scored)	GlaxoSmithKline

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

Cimetidine Hydrochloride

Routes	Dosage Forms	Strengths	Brand Names	Manufacturer
Oral	Solution	300 mg (of cimetidine) per 5 mL*	Tagamet HCl (with alcohol 2.8% parabens and propylene glycol)	GlaxoSmithKline
Parenteral	Injection	150 mg (of cimetidine) per mL	Cimetidine Hydrochloride Injection	Endo, Hospira, Sicor
	Injecti