Before you begin taking a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should take Allopurinol.

Drowsiness/reduced alertness: Allopurinol may cause drowsiness, affecting your ability to drive or operate machinery. Avoid driving, operating machinery, or performing other potentially hazardous tasks until you have determined how you are affected by Allopurinol.

Use appropriate caution if you plan to do activities requiring alertness.

Gout: Do not start allopurinol treatment until an acute attack of gout has completely subsided, as further attacks may be caused by Allopurinol. Acute gout attacks may occur at the start of treatment with allopurinol for people who have not taken the medication before. If an acute gout attack develops after starting Allopurinol, call your doctor.

Hypersensitivity syndrome: A Anaphylaxis (severe allergic reaction) called hypersensitivity syndrome has occurred for some people with the use of allopurinol. This reaction involves a number of organs in the body and may be fatal if not treated quickly. Stop taking the medication and get immediate medical attention if you have symptoms of a severe allergic reaction, including fever, swollen glands, yellowing of the skin or eyes, or flu-like symptoms with skin rash or blistering.

Kidney function: Kidney Disease or reduced kidney function may cause Allopurinol to build up in the body, causing side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how Allopurinol may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Allopurinol, and whether any special monitoring is needed.

Liver function: Allopurinol may reduce liver function and can cause liver failure. If you have liver problems, discuss with your doctor how Allopurinol may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Allopurinol, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking Allopurinol.

If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Skin rash: If you develop a skin rash, stop taking Allopurinol and contact your doctor. The skin rash may be the first sign of a serious allergic reaction to the medication.

Pregnancy: Allopurinol is not recommended for women who are or may become pregnant unless the potential benefits outweigh the possible risks. If you are or may be pregnant, talk to your doctor about the risks and benefits of Allopurinol.

Breast-feeding: Allopurinol passes into breast milk. If you are a breast-feeding mother and are taking allopurinol, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: Children should not take allopurinol, except in cases where increased uric acid levels in the blood are associated with cancer or with Lesch-Nyhan syndrome. The safety and effectiveness of allopurinol for this age group have not been established in treatment of other conditions.