H2Bloc Adverse Reactions

Famotidine is generally well tolerated; most adverse effects have been mild and transient.
The most frequently reported adverse effects (> 1%) are constipation, diarrhea, dizziness, and headache.
Less common adverse effects (≤ 1% of patients) include: Blood and Lymphatic System: Agranulocytosis, eosinophilia, leukocytosis, leukopenia, neutropenia, pancytopenia, prolonged erythrocyte sedimentation rate, thrombocytopenia.
Immune System: Anaphylaxis, angioedema, conjunctival congestion, orbital or facial edema, rash, urticaria.
Psychiatric: Disorientation, insomnia, reversible psychic disturbances (reversible in cases for which follow-up was obtained, including hallucinations, confusions, agitation, depression, anxiety, decreased libido).
Nervous System: Paresthesia, seizures/convulsions (epileptic, grand mal, particularly in patients with renal impairment), somnolence, taste disorder.
Cardiovascular Effects: Arrhythmia, AV block, bradycardia, hypertension, palpitation, prolonged QT interval in patients with impaired renal function.
Respiratory, Thoracic and Mediastinal: Bronchospasm, interstitial pneumonia.
Gastrointestinal: Abdominal discomfort or distension, belching, dry mouth, dysgeusia, flatulence, heartburn, vomiting.
Hepatobiliary: Cholestatic jaundice, hepatitis, hepatomegaly, intrahepatic cholestasis (visible sign: jaundice), liver enzyme abnormalities (alanine transaminase, aspartate transaminase, gamma-glutamyl transpeptidase, alkaline phosphatase, bilirubin).
Skin and Subcutaneous Tissue: Acne, alopecia, dry skin, flushing, pruritus, Stevens-Johnson syndrome, toxic epidermal necrolysis.
Musculoskeletal: Musculoskeletal pain including muscle cramps, arthralgia.
Reproductive and Breast: Gynecomastia, impotence, menstrual abnormalities.
General Disorders and Administration Site Conditions: Asthenia, chest tightness, fatigue, fever.
Others: Anorexia, changes in serum protein or cholesterol concentrations, increase in blood urea nitrogen or serum creatinine, tinnitus.
Additional Undesirable Effect for Injection Use: General Disorders and Administration Site Conditions: Transient irritation at the injection site.