Allopurinol
How this therapy is used at Arthritis Care of Texas in Corpus Christi, TX — what it is, how it is taken, side effects, and safety checks.
- Treats
- Gout
- How given
- Pill
- How often
- Once daily
Allopurinol is a cause-treating medicine: it lowers uric acid, which dissolves the crystals behind gout and prevents future flares and joint damage over months. It does not relieve the pain of a flare happening today — flare pain is treated separately — and it must be taken daily, long-term, even when you feel perfectly well.
What it is: A long-term treatment for the prevention of gout. The body produces urate, normally dissolved in the blood and excreted in urine; excess urate forms crystals in and around joints, causing inflammation and pain. Allopurinol blocks xanthine oxidase, reducing urate production so crystals dissolve and future attacks are prevented. Urate falls over weeks; dissolving existing crystals takes longer, and gout attacks may temporarily increase at first — this doesn't mean it isn't working. Attacks usually stop within a year once urate is low enough. It is offered when blood tests show high urate plus repeated attacks, joint or kidney damage, or gouty tophi (urate deposits in the skin). Use with caution if kidney or liver function is significantly impaired.
How it's taken: A tablet once daily after food, swallowed with water. The starting dose is 100–300 mg daily; your doctor adjusts it with blood tests (up to 900 mg in severe cases; lower doses for kidney or liver disease), with checks every few months once stable. It is NOT for acute attacks, and it is generally needed for life. Keep taking it even if it doesn't seem to work at first, even with early attacks, and even after attacks stop.
Side effects: Most people have none. Possible: skin rash (stop and see a doctor straight away if a rash develops), headache, drowsiness or dizziness (don't drive), nausea, taste disturbance, vomiting. A desensitisation restart is sometimes possible. Starting allopurinol can trigger gout attacks initially — you will usually be given an NSAID, colchicine, or steroids for the first few months. If an acute attack occurs while on it, don't stop — treat the attack normally. Alternatives if allopurinol is unsuitable: febuxostat, or benzbromarone/sulfinpyrazone, which increase urate excretion.
Interactions: Do not generally combine with azathioprine or mercaptopurine. It may increase rash risk with ampicillin/amoxicillin, and may increase the effect of warfarin (more clotting tests). Discuss all new medicines with your doctor.
Pregnancy: It is rare for women to get gout before menopause, and allopurinol is unlikely to affect fertility. Its effect on the unborn baby is unknown — don't take it if pregnant, and discuss with your doctor if planning a family. It passes into breast milk (risk unknown) — don't breastfeed on it.
Why the checks: The checks have clear reasons: kidney tests set a dose your body can clear safely; the uric acid level is the target we titrate against (usually below 6 mg/dL), so follow-up levels tell us whether the dose is right; and a gene test is sometimes done for patients of certain ancestries, because a gene variant raises the chance of a serious skin reaction — knowing in advance lets us choose a different plan.
Used for Gout
Common worries
I started it and got a flare — is it making my gout worse?
This is common and expected: as uric acid levels shift, crystal deposits stir and flares can occur in the first months. That is why a preventive medicine is often prescribed alongside at the start. The flare means chemistry is changing, not that the drug is wrong for you.
Why check my kidneys to set the dose?
Allopurinol is processed and cleared in ways that depend on kidney function, so the dose is matched to your kidneys — effective, but not more than they can handle.
Can I stop it once the flares stop?
No — flares stopping means your uric acid is controlled, not that the tendency is gone. Stopping lets levels climb back and flares return. It is a long-term, usually lifelong, medicine.
Ready to be seen? New patients are seen within 2–4 weeks.