Acid Reducer-Cimetidine Side Effects
Generic name: cimetidine
Medically reviewed by Drugs.com. Last updated on Nov 22, 2021.
Note: This document contains side effect information about cimetidine. Some of the dosage forms listed on this page may not apply to the brand name Acid Reducer-Cimetidine.
For the Consumer
Applies to cimetidine: oral liquid and tablets, parenteral injection, parenteral injection for iv infusion only
Side effects include:
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
Very common (10% or more): Increased plasma creatinine (up to 11%)
Rare (0.01% to 0.1%): Interstitial nephritis[Ref]
Interstitial nephritis cleared with drug withdrawal.
Creatinine elevations usually occurred during the first week of treatment and were typically non-progressive, with values returning to pretreatment levels during therapy or up to 1 week after stopping treatment.[Ref]
Pancreatitis cleared with drug withdrawal.[Ref]
Common (1% to 10%): Musculoskeletal pain, myalgia/reversible myalgia
Rare (0.01% to 0.1%): Arthralgia/reversible arthralgia, exacerbation of joint symptoms, polymyositis[Ref]
Common (1% to 10%): Dizziness, drowsiness, headache[Ref]
Headaches occurred more frequently in patients given 1600 mg/day compared to patients given 800 mg/day.
Somnolence and dizziness were usually mild and have been reported in patients receiving 800 to 1600 mg/day.[Ref]
Common (1% to 10%): Rash/skin rashes
Rare (0.01% to 0.1%): Hypersensitivity vasculitis
Hypersensitivity vasculitis usually cleared with drug withdrawal.[Ref]
Fever cleared with drug withdrawal.[Ref]
Common (1% to 10%): Tiredness
Rare (0.01% to 0.1%): Fever[Ref]
Confusional states occurred within 2 to 3 days of starting treatment, were reversible within 3 to 4 days of stopping treatment and were more commonly reported in elderly patients and/or ill patients (e.g., renal dysfunction, organic brain syndrome).[Ref]
Uncommon (0.1% to 1%): Confusional state, depression, hallucination
Uncommon (0.1% to 1%): Hepatitis, reversible liver damage
Rare (0.01% to 0.1%): Cholestatic effects, increased serum transaminases, mixed cholestatic-hepatocellular effects
Very rare (less than 0.01%): Fatal hepatic effects
Frequency not reported: Periportal hepatic fibrosis, severe parenchymal injury[Ref]
Hepatitis and serum transaminase level elevations cleared with drug withdrawal.
Fatal hepatic effects have occurred with other histamine-2 receptor antagonists.
Severe parenchymal injury is considered highly unlikely due to the predominance of cholestatic features.
There was a report of biopsy-proven periportal hepatic fibrosis in a patient receiving this drug.[Ref]
Uncommon (0.1% to 1%): Leukopenia
Leukopenia and/or thrombocytopenia were reversible with withdrawal of treatment.
Agranulocytosis/decreased white blood cell counts have been reported, with some events recurring upon rechallenge. These events were more commonly reported in patients with serious concomitant illnesses and/or those who received drugs/treatments known to produce neutropenia.[Ref]
Uncommon (0.1% to 1%): Tachycardia
Uncommon (0.1% to 1%): Reversible impotence
Rare (0.01% to 0.1%): Urinary retention
Very rare (less than 0.01%): Galactorrhea[Ref]
Urinary retention cleared with drug withdrawal.[Ref]
Uncommon (0.1% to 1%): Gynecomastia[Ref]
Rare (0.01% to 0.1%): Allergic reactions, anaphylaxis[Ref]
Very rare (less than 0.01%): Strongyloidiasis hyperinfection[Ref]
In a large epidemiological study, it was suggested that patients taking histamine-2-receptor antagonists had an increased adjusted relative risk of 1.63 (95% confidence interval of 1.07 to 2.48) of developing pneumonia compared to patients who stopped treatment. However, causal relationship between H2RA use and pneumonia has not been established.[Ref]
Frequency not reported: Pneumonia[Ref]
Frequently asked questions
More about Acid Reducer-Cimetidine (cimetidine)
Related treatment guides
1. "Product Information. Tagamet (cimetidine)." SmithKline Beecham (2001):
2. "Product Information. Tagamet HB (cimetidine)." SmithKline Beecham (2002):
3. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
4. Cerner Multum, Inc. "Australian Product Information." O 0
Some side effects may not be reported. You may report them to the FDA.