Diarrhea; transient intestinal cramps have occurred very rarely. Domperidone may cause abnormal liver function test.
QTc prolongation, ventricular arrhythmia, and sudden death have been reported. Other adverse events include life-threatening tachyarrhythmias, atrial fibrillation, ventricular tachycardia, bradycardia, palpitation, torsades de pointes, and cardiac arrest.
Central effects such as extrapyramidal reactions (Parkinson-like movements), including acute dystonic reactions (sustained muscle contractions which cause twisting and repetitive movements), convulsions; drowsiness, dry mouth, headache/migraine, insomnia, somnolence, nervousness, agitation, dizziness, thirst, lethargy, irritability.
Increased prolactin levels leading to galactorrhea (excessive milk production), mastalgia (breast pain), amenorrhea (missed menstrual periods), gynecomastia (breast enlargement), or decreased libido may occur. Gynecomastia without galactorrhea has also been reported.
Domperidone has been shown to increase levels of thyroid stimulating hormone (TSH) in hypothyroid women.
Urticaria, allergic/anaphylactic reactions and angioneurotic edema have occurred very rarely.
Skin rashes and itch.