What to Expect When Starting Allopurinol
Medical Disclaimer: This content is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider before starting, stopping, or changing any medication. Using this site does not create a doctor-patient relationship.
Drug information changes as the FDA updates labeling, and we cannot guarantee it is complete or current. Verify critical details with your pharmacist or physician.
Emergencies: If you think you may have a medical emergency, call 911 immediately. For a suspected overdose, call Poison Control at 1-800-222-1222. Report side effects to the FDA MedWatch program at fda.gov/medwatch or 1-800-FDA-1088.
See our Terms of Use and Editorial Policy.
Introduction
Allopurinol is a xanthine oxidase inhibitor used to lower uric acid levels in patients with gout, kidney stones, or certain cancers. It prevents new gout attacks by reducing uric acid production, but it does not relieve an acute flare already in progress. Many patients experience a temporary increase in gout attacks during the first few months as uric acid levels shift.
Week-by-week timeline
Starting Low and Slow
Allopurinol is typically started at 100 mg daily (or lower in patients with kidney disease) and increased gradually. You may experience mild nausea or stomach upset. Do not stop even if you have a gout flare — stopping and restarting disrupts uric acid levels further.
Possible Increase in Gout Flares
Paradoxical gout flares are common in the first 1-3 months as uric acid crystals mobilize from joints. Your doctor may prescribe a prophylactic anti-inflammatory (colchicine or naproxen) during this period. This is expected and does not mean the medication is not working.
Dose Titration
Your doctor will check serum uric acid levels and may increase the dose every 2-4 weeks until the target (below 6 mg/dL, or below 5 mg/dL for tophaceous gout) is reached. Doses range from 100-800 mg/day.
Uric Acid Reduction
Uric acid levels should be declining measurably. Flare frequency typically begins to decrease after the first 3 months of being at goal uric acid levels.
Long-Term Stabilization
Most patients experience significantly fewer gout attacks. Tophi (uric acid deposits) may begin to shrink over 6-12 months on effective therapy. Allopurinol is a lifelong medication for most gout patients.
When to call your doctor
Contact your healthcare provider if you experience:
- Skin rash — stop immediately and call your doctor (can be a sign of serious hypersensitivity syndrome, especially in the first 3 months)
- Fever, swollen lymph nodes, or flu-like symptoms (possible drug hypersensitivity reaction)
- Severe allergic reaction: difficulty breathing, facial swelling, hives
- Painful urination or blood in urine
- Unusual bruising or bleeding
- Yellowing of skin or eyes
Tips for getting started
Never stop allopurinol during a gout flare — this worsens uric acid fluctuations. Take it with food to reduce stomach upset. Drink 8-10 glasses of water daily to help kidneys excrete uric acid. Avoid high-purine foods (organ meats, shellfish, beer) and limit alcohol. Your doctor should check uric acid levels and kidney function at follow-up visits.
Frequently asked questions
More about Allopurinol
References
- [Regulatory] FDA Label: Allopurinol Tablets https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/016084s047lbl.pdf Accessed 2026-03-01.
- [Regulatory] NIH MedlinePlus: Allopurinol https://medlineplus.gov/druginfo/meds/a682673.html Accessed 2026-03-01.
- [Regulatory] ACR Gout Guidelines 2020 https://www.rheumatology.org/Practice-Quality/Clinical-Support/Clinical-Practice-Guidelines/Gout Accessed 2026-03-01.
Written and fact-checked by PrescriptionDrugs.org Editorial Team
Last updated: