Side Effects of Allopurinol


Allopurinol is a medication commonly used to treat conditions such as gout and kidney stones caused by high levels of uric acid in the body. While it is generally well-tolerated by most individuals, there are potential side effects that should be taken into consideration. This article aims to provide a comprehensive overview of the possible side effects of allopurinol and their implications.

1. Common Side Effects

Allopurinol may cause several common side effects, which usually subside as the body adjusts to the medication. These include:

  • Skin rash
  • Mild stomach upset
  • Drowsiness or dizziness
  • Headache
  • Increase in liver enzymes

It is important to note that these side effects are generally mild and do not require immediate medical attention. However, if they persist or worsen, it is recommended to consult a healthcare professional.

2. Serious Side Effects

While rare, allopurinol can cause more serious side effects that require immediate medical attention. These include:

  • Allergic reactions such as severe skin rash, itching, or hives
  • Swelling of the face, lips, tongue, or throat
  • Breathing difficulties
  • Chest pain or irregular heartbeat
  • Unusual bleeding or bruising
  • Fever, sore throat, or flu-like symptoms

If any of these serious side effects occur, it is crucial to seek medical help promptly as they can indicate a severe allergic reaction or other potentially harmful complications.

3. Drug Interactions

Allopurinol may interact with certain medications, leading to potential side effects or reducing the effectiveness of either drug. It is important to inform healthcare providers about all medications being taken to avoid any adverse interactions. Some commonly known drug interactions with allopurinol include:

  • Azathioprine
  • Mercaptopurine
  • Warfarin
  • Cyclosporine
  • Theophylline

These are not the only medications that may interact with allopurinol, so it is crucial to consult a healthcare professional or pharmacist before starting or stopping any medications.

4. Precautions and Warnings

Individuals should be cautious when taking allopurinol, especially if they have certain medical conditions or risk factors. It is important to discuss any relevant medical history with a healthcare provider before starting allopurinol. Precautions and warnings may include:

  • Kidney or liver disease
  • History of allergic reactions
  • Pregnancy or breastfeeding
  • Diabetes
  • High blood pressure

In some cases, dosage adjustments or alternative treatments may be necessary to minimize potential risks.

5. Rare Side Effects

Although rare, allopurinol can cause certain side effects that may require medical attention. These include:

  • Decreased blood cell counts
  • Severe skin reactions such as Stevens-Johnson syndrome or toxic epidermal necrolysis
  • Visual disturbances
  • Joint pain or swelling
  • Muscle pain or weakness

While these side effects are uncommon, it is important to be aware of their possibility and seek medical advice if they occur.

6. Dosage and Administration

The appropriate dosage of allopurinol may vary depending on the individual’s specific condition and medical history. It is important to follow the prescribed dosage and administration instructions provided by the healthcare provider. Failure to do so may increase the risk of side effects or reduce the effectiveness of the medication.

Allopurinol is typically taken orally, with or without food. It is important to drink plenty of fluids while taking this medication to prevent kidney stones. Regular monitoring of uric acid levels and liver function may be required during treatment to ensure the medication’s effectiveness and safety.

7. Frequently Asked Questions (FAQs)

Q1: Can allopurinol cause weight gain?

A1: Weight gain is not a commonly reported side effect of allopurinol. However, if you experience sudden or unexplained weight gain while taking allopurinol, it is recommended to consult your healthcare provider for further evaluation.

Q2: Can allopurinol be taken during pregnancy?

A2: The use of allopurinol during pregnancy should be discussed with a healthcare provider. In some cases, the benefits of treatment may outweigh the potential risks. However, individual circumstances and medical history should be taken into consideration before making a decision.

Q3: Can allopurinol be used to treat acute gout attacks?

A3: Allopurinol is not typically used to treat acute gout attacks. It is primarily used as a long-term preventive medication to lower uric acid levels and prevent future gout attacks. For acute gout attacks, other medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) or colchicine may be prescribed.

Q4: Can allopurinol cause liver damage?

A4: Allopurinol has been rarely associated with liver damage. Regular monitoring of liver function is recommended during treatment to detect any potential abnormalities. If you experience symptoms such as yellowing of the skin or eyes, dark urine, or persistent abdominal pain, it is important to seek medical attention immediately.

Q5: Is it safe to consume alcohol while taking allopurinol?

A5: Alcohol consumption should be discussed with a healthcare provider while taking allopurinol. Alcohol can increase the production of uric acid in the body, potentially counteracting the medication’s effects. Additionally, alcohol can also interfere with liver function, which may be relevant for individuals taking allopurinol.

Q6: Can allopurinol cause kidney stones?

A6: Allopurinol is actually prescribed to prevent the formation of kidney stones by lowering uric acid levels in the body. However, if you experience any symptoms of kidney stones such as severe pain in the back or side, blood in the urine, or frequent urination, it is important to seek medical attention for further evaluation.

Q7: How long does it take for allopurinol to start working?

A7: The effects of allopurinol may not be immediately noticeable. It may take several weeks or even months for the medication to effectively lower uric acid levels in the body. It is important to continue taking the medication as prescribed and follow up with healthcare providers for monitoring and adjustments if necessary.

Q8: Can allopurinol be used in children?

A8: Allopurinol is generally not recommended for use in children unless specifically prescribed by a pediatric specialist. The safety and efficacy of allopurinol in pediatric populations may vary, and careful consideration should be given to individual circumstances and medical guidance.

Q9: Can allopurinol cause hair loss?

A9: Hair loss is not a commonly reported side effect of allopurinol. If you experience significant hair loss while taking allopurinol, it is recommended to consult your healthcare provider to investigate other potential causes.

Q10: Can allopurinol be discontinued abruptly?

A10: Abruptly discontinuing allopurinol is generally not recommended. Sudden withdrawal of the medication can lead to a rapid increase in uric acid levels in the body, potentially triggering gout attacks. It is important to consult a healthcare provider before making any changes to the medication regimen.


Allopurinol is an effective medication for managing conditions related to high uric acid levels, such as gout and kidney stones. While it is generally safe and well-tolerated, it is crucial to be aware of the potential side effects and take necessary precautions. Regular communication with healthcare providers and adherence to prescribed dosages and instructions can help minimize the risk of adverse effects and ensure the best possible outcomes.

Rate article
Add a comment