Allopurinol: What it does and who it helps

Allopurinol is a medicine that lowers uric acid. Doctors prescribe it mainly to prevent gout attacks and to help people who form kidney stones from uric acid. It won’t stop a sudden gout flare once it starts, but over weeks to months it lowers the blood levels that cause crystals and pain.

How to take allopurinol

Most people start on a low dose, often 100 mg once daily, and the doctor raises it until uric acid reaches a target level. Some patients need 300 mg or more daily. If you have kidney problems your doctor will pick a lower dose and check you more often. Take it with water, and you can take it with or without food. Keep taking it even when you feel better — stopping can let uric acid climb again.

Important practical tip: when you begin allopurinol, gout attacks can happen more often for a few months. Doctors often give a short course of colchicine or an NSAID to prevent these early flares. If pain or swelling starts, don’t stop allopurinol without talking to your prescriber.

Side effects, warning signs, and interactions

Most people tolerate allopurinol well. Common mild effects include stomach upset or a rash. A new rash matters — if you get one, contact your doctor right away. Rarely, allopurinol can cause a serious allergic reaction with fever, sore throat, or liver or kidney problems. That needs urgent care.

Drug interactions to watch for: allopurinol can increase the effects or toxicity of azathioprine and mercaptopurine, so these should not be taken together without close supervision. It can also change how warfarin works — your INR may need closer monitoring. Always tell your clinician about every medicine and supplement you use.

Labs matter. Your doctor may check kidney and liver tests and measure serum uric acid. If you have chronic kidney disease, dose changes and more frequent checks are common. Pregnant or breastfeeding? Talk to your doctor — use is usually decided case by case.

Buying tips and safety online: allopurinol is a prescription drug in most countries. Use a licensed pharmacy and make sure it asks for a prescription. Look for clear contact info, pharmacist access, and secure checkout. Avoid sites that sell prescription drugs without a prescription or offer prices that look too good to be true. When the package arrives, check that the label and pills match the prescription.

Simple daily advice: take the dose your doctor prescribed, keep follow-up lab tests, report new rashes or fever, and be honest about other drugs you use. If you’re unsure whether to start or stop allopurinol, call your healthcare provider. Small steps — like regular testing and a reliable pharmacy — make it safer and more effective over time.