generic for Zyloprim

Allopurinol Side Effects

Stomach upset, nausea, diarrhea, or drowsiness may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if any of these rare but very serious side effects occur: numbness/tingling of arms/legs, easy bleeding/bruising, unusual tiredness, signs of kidney problems (such as change in the amount of urine, painful/bloody urination), yellowing eyes/skin, severe stomach/abdominal pain, persistent nausea/vomiting, dark urine, unusual weight loss, eye pain, vision changes.

This medication can commonly cause a rash that is usually not serious. However, you may not be able to tell it apart from a rare rash that could be a sign of a severe reaction. Get medical help right away if you develop any rash.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: fever, swollen lymph nodes, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
  • hypercalcemia
  • hemolytic anemia
  • pancytopenia
  • bone marrow depression
  • aplastic anemia
  • anemia
  • purpura
  • thrombocytopenic disorder
  • agranulocytosis
  • leukopenia
  • eosinophilia
  • leukocytosis
  • lymphocytosis
  • acute confusion
  • libido changes
  • depression
  • peripheral neuropathy
  • myopathy
  • iritis
  • cataracts
  • amblyopia
  • conjunctivitis
  • optic neuritis
  • tinnitus
  • pericarditis
  • bradycardia
  • vasculitis
  • thrombophlebitis
  • ecchymosis
  • vasodilation of blood vessels
  • pharyngitis
  • rhinitis
  • asthma
  • bronchospastic pulmonary disease
  • sialoadenitis
  • stomatitis
  • gastritis
  • dyspepsia
  • hepatic necrosis
  • drug-induced hepatitis
  • obstructive hyperbilirubinemia
  • acute pancreatitis
  • gastrointestinal hemorrhage
  • nephritis
  • renal failure
  • kidney stone
  • hematuria
  • male infertility
  • erectile dysfunction
  • gynecomastia
  • furunculosis
  • allergic dermatitis
  • erythema multiforme
  • toxic epidermal necrolysis
  • Stevens-Johnson syndrome
  • exfoliative dermatitis
  • lichen planus
  • pruritus of skin
  • onycholysis
  • alopecia
  • urticaria
  • arthralgia
  • myalgia
  • drowsy
  • memory impairment
  • vertigo
  • dizziness
  • insomnia
  • fever
  • hyperhidrosis
  • dysgeusia
  • skin rash
  • edema
  • facial edema
  • anorexia
  • headache disorder
  • epistaxis
  • lymphadenopathy
  • nausea
  • vomiting
  • diarrhea
  • abdominal pain with cramps
  • proteinuria
  • abnormal hepatic function tests
  • hypersensitivity drug reaction
  • paresthesia
  • general weakness
  • jaundice
  • DRESS syndrome

Drug Interactions

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (such as prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug are: "blood thinners" (e.g., warfarin), capecitabine, didanosine.