Tagamet HB Side Effects
Generic Name: cimetidine
Note: This page contains side effects data for the generic drug cimetidine. It is possible that some of the dosage forms included below may not apply to the brand name Tagamet HB.
More frequent side effects include: gynecomastia. See below for a comprehensive list of adverse effects.
For the Consumer
Applies to cimetidine: oral liquid and tablets, parenteral injection, parenteral injection for iv infusion only
Side effects include:
Headache, dizziness, somnolence, diarrhea.
With ≥1 month of therapy: gynecomastia.
With IM therapy: transient pain at injection site.
For Healthcare Professionals
Applies to cimetidine: compounding powder, intravenous solution, oral liquid, oral tablet
Nervous system side effects have included headache (up to 3.5%), dizziness (1%), and somnolence (1%). Severe mental status changes, including depression, agitation, disorientation, confusion, delirium, unsteadiness, slurred speech, lethargy, hallucinations, and coma, while uncommon, have been reported frequently in the literature. Other nervous system effects reported are extrapyramidal symptoms, cerebellar syndrome with encephalopathy, and paresthesias. Critical illness, advanced age, renal, and/or liver disease appear to be associated with an increased risk for central nervous system toxicity.[Ref]
The mechanism by which cimetidine induces mental status changes is not well established but appears to involve increased serum concentrations of cimetidine and, possibly, cimetidine sulfoxide. Advanced age has been implicated in many case reports of mental status changes, however, the pharmacokinetics of cimetidine correlate more closely with renal function, making renal dysfunction associated with advanced age a more likely risk factor than age itself. In addition, enhanced cimetidine penetration of the blood brain barrier has been demonstrated in patients with liver disease. Onset of symptoms have usually developed within 2 to 3 days of start of therapy, but may be delayed. Following discontinuation of cimetidine, mental status usually normalizes over several days.[Ref]
Psychiatric side effects may accompany other signs and symptoms of neurologic toxicity such as unsteadiness, slurred speech, and lethargy. Age, renal dysfunction, and/or liver disease may be predisposing factors in these cases.
Psychiatric side effects in the form of severe depression, suicidal ideation, paranoia, and frank psychosis have also been reported in otherwise healthy patients.[Ref]
Psychiatric side effects have included depression, paranoia, agitation, mania, hallucinations, psychosis, and loss of libido. These side effects may be accompanied by other signs and symptoms of neurologic toxicity. Critical illness, advanced age, renal, and/or liver disease appear to be associated with an increased risk for central nervous system toxicity, including psychiatric disturbances.[Ref]
Endocrine side effects have included gynecomastia, occurring in 0.3% to 1% of patients treated for nonhypersecretory conditions for 1 month or longer. In patients treated for pathologic hypersecretory conditions, this occurred in about 4% of cases. In the majority of cases, however, hormone levels remain in the normal range. In addition, galactorrhea, impotence, and transient alopecia as well as a case of possible cimetidine-induced hypoparathyroidism have been reported.[Ref]
A large population-based cohort study involving 81,535 men evaluated the risk of gynecomastia associated with cimetidine, ranitidine, misoprostol, and omeprazole. Overall, 37,202 men received cimetidine. Gynecomastia developed in 86 men treated with cimetidine. The relative risk of gynecomastia during cimetidine treatment compared to a control population not treated with cimetidine was 7.2. Use of daily doses of 1000 mg or more was associated with a relative risk of 43.5.
Luteinizing hormone (LH), follicle-stimulating hormone (FSH), serum prolactin, testosterone, and estradiol levels are usually within the normal range in patients who develop gynecomastia or breast tenderness while on cimetidine. However, decreases in serum testosterone and increases in LH and estradiol as well as increases in serum prolactin have been reported on occasion.
Severe hypocalcemia was reported in an elderly woman treated with cimetidine postoperatively. There was some evidence in this case to support a possible cimetidine-induced reduction in parathyroid hormone with subsequent hypocalcemia. More study is needed to confirm this.[Ref]
In a study involving medical ICU patients requiring invasive blood pressure monitoring for circulatory instability or with a need for repeated arterial blood gas draws, an average decrease of 14 mmHg in systolic and 9 mmHg in diastolic pressure was noted in 74% (50/68) of patients following administration of cimetidine (the active ingredient contained in Tagamet HB) 200 mg IV over 3 minutes. In 13% of patients, systolic pressure decreased by more than 30 mmHg.
Most cardiovascular side effects are noted following rapid intravenous administration. While administration by slow infusion appears to reduce the incidence of such effects, serious cardiovascular events, including sinus arrest, have been reported with continuous intravenous infusions as well as oral administration.[Ref]
Cardiovascular side effects have been rarely reported. These are usually associated with rapid intravenous administration. Tachycardia, bradycardia, hypotension, QT interval prolongation, premature ventricular contractions, junctional rhythm, AV block, and sinus arrest have been reported with H2 receptor antagonist.[Ref]
Hematologic side effects have rarely included leukopenia, eosinophilia, neutropenia, thrombocytopenia, agranulocytosis, and aplastic anemia. The manufacturer also reports extremely rare cases of autoimmune hemolytic anemia.[Ref]
Rare cases of irreversible or fatal blood dyscrasias have been reported in the literature. While rare, hematologic abnormalities should be considered in patients treated with cimetidine who develop fever, chills, sore throat, easy bruising, and other signs or symptoms suggestive of a blood dyscrasia.[Ref]
Hepatic side effects have included elevations in liver function tests and hepatitis of both cholestatic and mixed cholestatic-hepatocellular types. Some presentations of cimetidine-induced hepatitis have features suggestive of a hypersensitivity response.[Ref]
Overall, serious hepatotoxicity due to cimetidine is rare. Bridging hepatic necrosis, centrilobular hepatic necrosis, and intrahepatic cholestasis have been noted on biopsy in cases of cimetidine-induced hepatitis. In some cases, liver toxicity has been associated with fever, rash, and eosinophilia, suggesting a hypersensitivity etiology.
Cimetidine-induced hepatitis in a patient with a history of famotidine-induced hepatitis has been reported in at least one case. Extreme caution is recommended when initiating cimetidine therapy in a patient with a history of other H2-antagonist-induced hepatotoxicity.
Liver injury, with fatal outcome, has been reported with the use of other H2 receptor antagonists.[Ref]
Renal side effects have included elevations in serum creatinine. However, such elevations are generally due to competitive inhibition of tubular secretion of creatinine rather than a result of impaired glomerular filtration or renal toxicity. Rare cases of acute renal failure and interstitial nephritis have been reported.[Ref]
Elevations in serum creatinine by as much as 20% are reported during cimetidine therapy. Cimetidine is thought to competitively inhibit the secretion of creatinine by the renal proximal tubules resulting in a reduction in creatinine clearance. Creatinine does not appear to affect cimetidine transport, except at very high concentrations.
Overt renal toxicity, such as renal failure and interstitial nephritis, is rare. In some cases, cimetidine-induced renal toxicity has been attributed to a delayed-type hypersensitivity.[Ref]
Gastrointestinal side effects have been reported rarely. These have included diarrhea (1%) which is generally mild although severe cases have been reported, nausea/vomiting (0.6%), constipation (0.2%), dry mouth, and taste changes. In addition, cases of parotitis, phytobezoars, and pancreatitis have been reported.[Ref]
Dermatologic side effects have included mild rash as well as severe dry skin (xerosis), seborrheic dermatitis, erythema annular centrifugum, erythema multiforme, Stevens-Johnson syndrome, exfoliative dermatitis, and toxic epidermal necrolysis. Reversible alopecia has also been reported rarely.[Ref]
Antiandrogen and sebum-inhibitory effects are proposed mechanisms by which cimetidine causes severe xerosis and asteatotic dermatitis.[Ref]
Musculoskeletal side effects have rarely included arthralgias, inflammatory arthritis, gout-like arthritis, and myalgias. The manufacturer reports rare cases of polymyositis although causality is unknown.[Ref]
Immunologic side effects have included a case of exacerbation of cutaneous systemic lupus erythematosus and cimetidine-induced cutaneous vasculitis. Strongyloidiasis hyperinfection has been reported rarely in immunocompromised patients.[Ref]
Hypersensitivity side effects have included urticaria, pruritus, fever, angioedema, and anaphylaxis. In addition, a case of drug fever in association with leukocytosis and abdominal pain has also been reported. Vasculitis has been reported. It resolved on discontinuation of the drug.[Ref]
1. Totte J, Scharpe S, Verkerk R, Neels H, Vanhaeverbeek M, Smitz S, Rousseau JJ "Neurological dysfunction associated with abnormal levels of cimetidine metabolite ." Lancet 1 (1981): 1047
2. Bateman DN, Bevan P, Longley BP, et al "Cimetidine induced postural and action tremor." J Neurol Neurosurg Psychiatry 44 (1981): 94
3. Bostrom R, Holmgren E, Lundberg D "Respiratory depression after cimetidine reversed by physostigmine." Intensive Care Med 8 (1982): 153-4
4. Sonnenblick M, Rosin AJ, Weissberg N "Neurological and psychiatric side effects of cimetidine: report of 3 cases with review of the literature." Postgrad Med J 58 (1982): 415-8
5. Romisher S, Felter R, Dougherty J "Tagamet-induced acute dystonia." Ann Emerg Med 16 (1987): 1162-4
6. Bastani B, Galli D, Gellens ME "Cimetidine-induced climacteric symptoms in a young man maintained on chronic hemodialysis." Am J Nephrol 18 (1998): 538-40
7. Levine ML "Cimetidine-induced coma in cirrhosis of the liver." JAMA 240 (1978): 1238
8. Handler CE, Besse CP, Wilson AO "Extrapyramidal and cerebellar syndrome with encephalopathy associated with cimetidine." Postgrad Med J 58 (1982): 527-8
9. Walls TJ, Pearce SJ, Venables GS "Motor neuropathy associated with cimetidine." Br Med J 281 (1980): 974-5
10. Kushner MJ "Chorea and cimetidine." Ann Intern Med 96 (1982): 126
11. Kimelblatt BJ, Cerra FB, Calleri G, et al "Dose and serum concentration relationships in cimetidine-associated mental confusion." Gastroenterology 78 (1980): 791-5
12. Russell WL, Lopez LM "Cimetidine-induced mental status changes: case report and literature review." Am J Hosp Pharm 37 (1980): 1667-71
13. Hubbard JR, Levenson JL, Patrick GA "Psychiatric side effects associated with the ten most commonly dispensed prescription drugs: a review." J Fam Pract 33 (1991): 177-86
14. Pierce JR "Cimetidine-associated depression and loss of libido in a woman." Am J Med Sci 286 (1983): 31-4
15. Adler LE, Sadja L, Wilets G "Cimetidine toxicity manifested as paranoia and hallucinations." Am J Psychiatry 137 (1980): 1112-3
16. "Product Information. Tagamet (cimetidine)." SmithKline Beecham, Philadelphia, PA.
17. Hubain PP, Sobolski J, Mendlewicz J "Cimetidine-induced mania." Neuropsychobiology 8 (1982): 223-4
18. Rodriguez LAG, Jick H "Risk of gynaecomastia associated with cimetidine, omeprazole, and other antiulcer." BMJ 308 (1994): 503-6
19. Ehrinpreis MN, Dhar R, Narula A "Cimetidine-induced galactorrhea." Am J Gastroenterol 84 (1989): 563-5
20. Vircburger MI, Prelevic GM, Brkic S, et al "Transitory alopecia and hypergonadotrophic hypogonadism during cimetidine treatment." Lancet 05/23/81 (1981): 1160-1
21. Lardinois CK, Mazzaferri EL "Cimetidine blocks testosterone synthesis." Arch Intern Med 145 (1985): 920-2
22. Edwards H, Zinberg J, King TC "Effect of cimetidine on serum calcium levels in an elderly patient." Arch Surg 116 (1981): 1088-9
23. Hall WH "Breast changes in males on cimetidine." N Engl J Med 295 (1976): 841
24. Drea EJ, Mutnick AH, Lam W, Palazzolo DP "Cimetidine-associated adverse reaction." DICP 24 (1990): 581-3
25. Ishizaki M, Yamada Y, Kido T, et al "First-degree atrioventricular block induced by oral cimetidine." Lancet 1 (1987): 225-6
26. Mahon WA, Kolton M "Hypotension after intravenous cimetidine." Lancet 1 (1978): 828
27. MacMahon B, Bakshi M, Walsh MJ "Cardiac arrhythmias after intravenous cimetidine." N Engl J Med 305 (1981): 832-3
28. Hulisz DT, Welko JR, Heiselman DE "Sinus arrest associated with continuous-infusion cimetidine." Pharmacotherapy 13 (1993): 64-7
29. Jefferys DB, Vale JA "Cimetidine and bradycardia." Lancet 1 (1978): 828
30. Watson AJ, Watson R, Keogh JA "Cimetidine induced arrhythmias." Ir J Med Sci 151 (1982): 348-50
31. Dickey W, Symington M "Broad-complex tachycardia after intravenous cimetidine." Lancet 1 (1987): 99-100
32. Kiowski W, Frei A "Bolus injection of cimetidine and hypotension in patients in the intensive care unit: incidence and mechanisms." Arch Intern Med 147 (1987): 153-6
33. de Galocsy C, de Strihou CV "Pancytopenia with cimetidine." Ann Intern Med 90 (1979): 274
34. Gafter U, Zevin D, Komlos L, et al "Thrombocytopenia associated with hypersensitivity to ranitidine: possible cross-reactivity with cimetidine." Am J Gastroenterol 84 (1989): 560-2
35. Tonkonow B, Hoffman R "Aplastic anemia and cimetidine." Arch Intern Med 140 (1980): 1123-4
36. Al-Kawas FH, Lenes BA, Sacher RA "Cimetidine and agranulocytosis." Ann Intern Med 90 (1979): 992-3
37. Crapper RM "Fatal agranulocytosis attributable to cimetidine." Med J Aust 2 (1981): 250-1
38. List AF, Beaird DH, Kummet T "Ranitidine-induced granulocytopenia: recurrence with cimetidine administration." Ann Intern Med 108 (1988): 566-7
39. Corbett CL, Holdsworth CD "Fever, abdominal pain, and leucopenia during treatment with cimetidine." Br Med J 1 (1978): 753-4
40. Tishler M, Abramov AL "Cimetidine-induced eosinophilia." Drug Intell Clin Pharm 19 (1985): 377-8
41. Harats N, Oren R, Heyman A, Naparstek Y "Cimetidine-induced thrombocytopenia in a cirrhotic patient." DICP 23 (1989): 177-8
42. Carloss HW, Tavassoli M, McMillan R "Cimetidine-induced granulocytopenia." Ann Intern Med 93 (1980): 57-8
43. Fitchen JH, Koeffler HP "Cimetidine and granulopoiesis: bone marrow culture studies in normal man and patients with cimetidine-associated neutropenia." Br J Haematol 46 (1980): 361-6
44. Strom BL, Carson JL, Schinnar R, Shaw M "Is cimetidine associated with neutropenia?" Am J Med 99 (1995): 282-90
45. Boyd PT, Lepre F, Dickey JD "Chronic active hepatitis associated with cimetidine." Br Med J 298 (1989): 324-5
46. Van Steenbergen W, Vanstapel MJ, Desmet V, et al "Cimetidine-induced liver injury: report of three cases." J Hepatol 1 (1985): 359-68
47. Lewis JH "Hepatic effects of drugs used in the treatment of peptic ulcer disease." Am J Gastroenterol 82 (1987): 987-1003
48. Lorenzini I, Jezequel AM, Orlandi F "Cimetidine-induced hepatitis: electron microscopic observations and clinical pattern of liver injury." Dig Dis Sci 26 (1981): 275-80
49. Schwartz JT, Gyorkey F, Graham DY "Cimetidine hepatitis." J Clin Gastroenterol 8 (1986): 681-6
50. Delpre G, Kadish U, Livni E "Hepatitis following cimetidine administration." Am J Med Sci 283 (1982): 153-6
51. del Arbol LR, Moreira V, Moreno A, et al "Bridging hepatic necrosis associated with cimetidine." Am J Gastroenterol 74 (1980): 267-9
52. Hashimoto F, Davis RL, Egli D "Hepatitis following treatments with famotidine and then cimetidine." Ann Pharmacother 28 (1994): 37-9
53. Pachon J, Lorber MI, Bia MJ "Effects of H2-receptor antagonists on renal function in cyclosporine-treated renal transplant patients." Transplantation 47 (1989): 254-9
54. Ducharme MP, Smythe M, Strohs G "Drug-induced alterations in serum creatinine concentrations." Ann Pharmacother 27 (1993): 622-33
55. Rudnick MR, Bastl CP, Elfenbein IB, et al "Cimetidine-induced acute renal failure." Ann Intern Med 96 (1982): 180-2
56. Larsson R, Bodemar G, Kagedal B "The effect of cimetidine, a new histamine H2-receptor antagonist, on renal function." Acta Med Scand 205 (1979): 87-9
57. Hake DH "Interstitial nephritis and cimetidine." Ann Intern Med 94 (1981): 416
58. Payne CR, Ackrill P, Ralston AJ "Acute renal failure and rise in alkaline phosphatase activity caused by cimetidine." Br Med J 285 (1982): 100
59. Pitone JM, Santoro JJ, Biondi RJ, et al "Cimetidine-induced acute interstitial nephritis." Am J Gastroenterol 77 (1982): 169-71
60. Seidelin R "Cimetidine and renal failure." Postgrad Med J 56 (1980): 440-1
61. Field R, Meyer GW "Diarrhea from cimetidine." N Engl J Med 299 (1978): 262
62. Humphries TJ, Myerson RM, Gifford LM, et al "A unique postmarket outpatient surveillance program of cimetidine: report on phase II and final summary." Am J Gastroenterol 79 (1984): 593-6
63. Caraman P, Netter P, Semin-Cosson AM, et al "Recurrent parotitis with H2 receptor antagonists." Lancet 2 (1986): 1455-6
64. Wilkinson ML, O'Driscoll R, Kiernan TJ "Cimetidine and pancreatitis." Lancet 03/14/81 (1981): 610-1
65. Nichols TW "Phytobezoar formulation: a new complication of cimetidine therapy." Ann Intern Med 95 (1981): 70
66. Greist MC, Epinette WW "Cimetidine-induced xerosis and asteatotic dermatitis." Arch Dermatol 118 (1982): 253-4
67. Yantis PL, Bridges ME, Pittman FE "Cimetidine-induced exfoliative dermatitis." Dig Dis Sci 25 (1980): 73-4
68. Kanwar AJ, Majid A, Garg MP, Singh G "Seborrheic dermatitis-like eruption caused by cimetidine." Arch Dermatol 117 (1981): 65-6
69. Horiuchi Y, Ikezawa K "Famotidine-induced erythema multiforme: cross-sensitivity with cimetidine." Ann Intern Med 131 (1999): 795
70. Tidwell BH, Patterson TM, Burford B "Cimetidine-induced toxic epidermal necrolysis." Am J Health Syst Pharm 55 (1998): 163-4
71. Davidson BL, Gilliam JN, Lipsky PE "Cimetidine-associated exacerbation of cutaneous lupus erythematosus." Arch Intern Med 142 (1982): 166-7
72. Tullio CJ, Roberts MA "Cimetidine-induced alopecia." Clin Pharm 4 (1985): 145
73. Merrett AC, Marks R, Dudley FJ "Cimetidine-induced erythema annulare centrifugum: no cross-sensitivity with ranitidine." Br Med J 283 (1981): 698
74. Einarson TR, Turchet EN, Goldstein JE, MacNay KR "Gout-like arthritis following cimetidine and ranitidine." Drug Intell Clin Pharm 19 (1985): 201-2
75. Khong TK, Rooney PJ "Arthritis associated with cimetidine." Lancet 12/20/80 (1980): 1380
76. Mitchell GG, Magnusson AR, Weiler JM "Cimetidine-induced cutaneous vasculitis." Am J Med 75 (1983): 875-6
77. Dernbach WK, Taylor G "Leukoclastic vasculitis from cimetidine." JAMA 246 (1981): 331
78. Sandhu BS, Requena R "Hypersensitivity to cimetidine." Ann Intern Med 97 (1982): 138
79. Knapp AB, Grimshaw RS, Goldfarb JP, et al "Cimetidine-induced anaphylaxis." Ann Intern Med 97 (1982): 374-5
80. Parenti CM, Hoffman JE "Hyperpyrexia associated with intravenous cimetidine therapy: report of a case." Arch Intern Med 146 (1986): 1821-2
81. Chia JKS, Kim DO, Lebow RC "Recurrent fever, leukocytosis, and abdominal pain due to treatment with cimetidine." Clin Infect Dis 18 (1994): 468-9
It is possible that some side effects of Tagamet HB may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.
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