What is Allopurinol?

Allopurinol is a drug that is used to lower elevated blood uric acid levels. It is marketed under the brand names Zyloprim and others. It is used to avoid gout, certain forms of kidney stones, and elevated uric acid levels that may occur as a result of chemotherapy. It's either taken orally or inserted into a vein.

Allopurinol Uses

Allopurinol is used for the treatment of gout and certain types of kidney stones. It is also used to prevent increased levels of uric acid in patients receiving chemotherapy for cancer. These patients may have increased levels of uric acid due to the release of uric acid from dying cancer cells. Allopurinol works by reducing the amount of uric acid produced by the body. Increased levels of uric acid may cause problems with the gut and kidneys.

How to use Allopurinol

  • This drug should be taken orally once a day or as instructed by your doctor. To relieve stomach upset, take this medicine after a meal. If your everyday dosage is more than 300 milligrams, you will need to take several smaller doses during the day (consult your doctor for directions).
  • Drink a full glass of water for each dose and at least 8 additional glasses (8 ounces each) of fluid during the day. Consult your doctor for further instructions if your doctor has advised you to drink less fluid for any medical purposes. Your doctor can also advise you on how to reduce acid in your urine (for example, by preventing high doses of ascorbic acid/vitamin C).
  • Dosage is determined by your medical condition and treatment reaction. To get the most advantages and benefits from this drug, take it every day. Take it at the same time every day to help you recall.
  • It may take several weeks for this drug to take effect in the treatment of gout. For several months after starting this drug, you may experience further gout attacks as your body loses excess uric acid. Allopurinol isn't an analgesic. Continue to take your prescribed gout medications (e.g., colchicine, ibuprofen, indomethacin) as instructed by your doctor to relieve gout pain.

Allopurinol Side Effects

  • Rash
  • Nausea
  • Renal failure
  • Vomiting
  • Joint pain
  • Blood disorders
  • Difficulty breathing
  • Cardiovascular abnormalities
  • Cataracts
  • Confusion
  • Dizziness
  • Bruise
  • Nosebleed
  • Foot drop
  • Blood in the urine
  • Liver damage
  • Decreased muscle tone
  • Inflammation of the iris in the eye
  • Kidney function abnormality
  • Severe vision impairment
  • Inflammation of the nerves
  • Sore throat
  • Itching


  • If you are allergic to allopurinol, or if you have had a bad reaction to it, or if you have any other reactions, alert your doctor or pharmacist before taking it. Inactive ingredients can be present in this product, causing allergic reactions or other issues.
  • Tell your doctor or pharmacist about any medical conditions you have, particularly if you have: liver disease, kidney disease, diabetes, high blood pressure (hypertension), or irregular diets (e.g., fasting).
  • This medication has the potential to make you drowsy. You can become drowsy if you consume alcohol. Do not drive, operate machinery, or engage in any other activity that requires alertness until you are sure you can do so safely. This drug's efficacy can be harmed by alcohol. Alcohol consumption should be restricted.
  • Kidney function deteriorates as you age. The kidneys eliminate this drug. As a result, older adults may be more susceptible to side effects while taking this medication.
  • This drug should only be taken during pregnancy when it is required urgently. Consult your doctor.
  • Breast milk contains allopurinol. Before you start breastfeeding, talk to your doctor.


Drug interactions can cause your drugs to function differently or put you at risk for severe side effects. Keep a list of all the medicines you use (including prescription and over-the-counter medications, as well as herbal remedies) and share it with your doctor and pharmacist. Without your doctor's permission, do not begin, stop, or alter the dosage of any medications.

Blood thinners (warfarin), capecitabine, and didanosine are some of the products that may interfere with this drug.

Missed Dose

If you forgot to take any dose, take it as soon as you recall it. But if it is near the time of the next dose, skip the forgotten dose. Take your next dosage at regular intervals of time. Do not double the dose.


If you or someone has taken too much of this medicine and has serious symptoms such as passing out or trouble breathing, seek emergency medical help. Symptoms of overdose can include severe drowsiness, fainting, seizures, fast heartbeat.


  • Do not share this medication with anyone else even if they have the same symptoms
  • Lab and medical tests such as blood pressure, liver function should be done while you are taking this medication. Consult your doctor for more details and information.


  • Store at room temperature far away from direct sunlight, heat, and moisture. Do not store in the bathroom as well. Keep all medications away from small kids.
  • Never flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it gets expired or no longer in use. Consult your pharmacist or local waste disposal company.

Allopurinol vs Colchicine



Also known Zyloprim Also known Colcrys
Lowers uric acid levels in the blood, and prevents gout flare-ups. Prevents and treats gout.
Used for treating Gout, High uric acid in cancer, Recurrent kidney stones Used for - Gout, Gout prevention, Familial Mediterranean fever, Behcet's disease, and Inflammation of the heart.
Dosage forms- Injection, Pill Dosage forms - Pill
Kidney stones can be formed while taking allopurinol, so you need to drink a lot of fluids to help prevent this. Doses need to be changed if you have kidney or liver problems.

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Frequently Asked Questions

What is allopurinol used for?

Allopurinol is a drug that lowers uric acid levels in the blood. It can build up and cause small, sharp crystals to form in and around your joints if you generate too much uric acid or your kidneys do not flush it out enough. Gout and kidney stones are treated with allopurinol.

What are the side effects of taking allopurinol?

Side effects of taking allopurinol are

  • Skin rashes
  • Headaches
  • Feeling drowsy
  • Dizzy
  • Feeling sick
  • Changes to your sense of taste

When should I take allopurinol in the morning or at night?

It will also assist you in remembering when you can take it. Once a day, allopurinol is normally taken. If your dose is greater than 300 mg, however, your doctor can encourage you to take it twice a day. It should then be taken in the morning and evening, after breakfast and dinner.

What is the recommended dosage of allopurinol?

Adults and children aged 11 and up can take 600 to 800 milligrams (mg) per day, split into two or three doses over two to three days. Children aged 6 to 10 years old can take 300 mg once a day for 2 to 3 days.

Is allopurinol bad for your heart?

Allopurinol use was linked to higher (not lower) modified risks of cardiovascular hospitalization (including coronary artery disease (CAD), hypertensive heart disease, heart failure, stroke, and other cardiovascular events) as compared to non-use.

Is allopurinol dangerous to the kidneys?

Allopurinol can help reduce serum urate levels and alleviate gout symptoms without putting the kidneys at risk.

Does allopurinol raise blood pressure?

Allopurinol is linked to a minor but substantial decrease in blood pressure. This influence may be used to help hypertensive patients with hyperuricemia regulate their blood pressure.

Does allopurinol damage the liver?

Allopurinol (Zyloprim), a drug commonly used to avoid painful gout attacks, can cause liver damage in as little as a few days to weeks after starting treatment. If you are prescribed this medication, your doctor will also advise you to have routine blood tests to check your liver's health.

How fast does allopurinol start working?

It may take up to two months for it to reach maximum effectiveness. It has no impact during a gout assault, but you can continue to take it on a daily basis even if this happens. Your blood levels of uric acid can rise for a short time within the first few weeks of taking allopurinol before falling.

Can allopurinol cause weight gain?

Weight loss is more likely with allopurinol than weight gain. With allopurinol, patients experience weight loss, nausea, and a loss of appetite. Acute gout attacks, diarrhea, nausea, and skin rash are all possible side effects of allopurinol.

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