What Are the Most Common Allopurinol Side Effects?

Most patients who take allopurinol do not experience any negative side effects, and when symptoms do develop, they are usually mild and do not necessitate cessation of the drug. The development of a skin rash and itching are the most commonly reported allopurinol side effects. Additional symptoms may include drowsiness, nausea, and diarrhea. More serious potential allopurinol side effects may include urinary problems or a severe allergic reaction that can be life threatening. Any questions or concerns about specific allopurinol side effects should be discussed with a doctor or other medical professional.

Nausea and diarrhea are frequently reported allopurinol side effects, although these symptoms are usually temporary and mild. Over-the-counter medications are generally successful at treating these symptoms, although if they are persistent or severe, a doctor should be consulted for further medical evaluation. Severe diarrhea may lead to dehydration, so extra fluids should be consumed in an effort to avoid this complication. Eye irritation, painful urination, or the presence of blood in the urine may indicate the development of serious complications and should be reported to a doctor right away.

The presence of an itchy rash is among the most common allopurinol side effects. When this occurs, the medication should be discontinued and a doctor should be consulted, as the rash may indicate the beginning of a type of severe allergic reaction known as anaphylaxis. Additional symptoms may include swelling of the face, lips, or tongue and difficulty breathing. Possible anaphylaxis symptoms should be treated as a medical emergency, as death may occur within a matter of minutes without immediate medical attention.

In the beginning portion of the treatment process, allopurinol side effects may include a worsening of the gout symptoms that the drug is designed to treat. This is a temporary complication and does not usually indicate a need to discontinue the medication. In order to prevent a worsening of these symptoms, an additional medication is often prescribed for a short period of time.

Liver and kidney damage may occur when using this medication, especially if it is taken over a prolonged period of time. A variety of blood disorders are also possible, so many doctors will order periodic blood testing to ensure that these problems are detected as quickly as possible. Hair loss, seizures, and peripheral neuropathy may develop while taking this medication. A doctor should be notified of any bothersome allopurinol side effects so that the situation can be evaluated and any dosage changes can be made before serious complications have a chance to develop.