Allopurinol (Zyloprim) Recommended dosage is 200-600 mg per day for Adults and children 11 years of age or older. Onset of action is 1-2 weeks. Increase your fluid intake to 3 liters per day. Do not crush or break enteric coated tablets Alcohol and caffeine must be avoided. Take medication with meals to avoid gastrointestinal upset. is caused by the overproduction of uric acid or decreased uric acid excretion. This results in inflammation of joints and tissues causing symptoms of pain. Side effects: Nausea Headache Drowsiness Diarrhea Adverse effect: Stevens-Johnson syndrome Azathioprine and Mercaptopurin NOTE: NOTE: This drug is used for short or longterm treatment.