Home Allopurinol (Oral Route)

Allopurinol (Oral Route)


Description and Brand Names of Allopurinol (Oral Route)

US Brand Name

  1. Zyloprim


Allopurinol is used to prevent or treat high uric acid levels in the blood. Gout or gouty arthritis (inflammation and pain in a joint) is caused by high uric acid levels. Allopurinol is a xanthine oxidase inhibitor that works by causing less uric acid to be produced by the body.

Allopurinol is also used to prevent or treat high uric acid levels that may be caused by cancer medicines or for patients with kidney stones that contain calcium.

This medicine is available only with your doctor’s prescription.

This product is available in the following dosage forms:

  • Capsule
  • Tablet

Before Using Allopurinol (Oral Route)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of allopurinol in children with high uric acid levels caused by cancer.


No information is available on the relationship of age to the effects of allopurinol in geriatric patients.



Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Didanosine

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Azathioprine
  • Captopril
  • Cyclophosphamide
  • Enalapril
  • Enalaprilat
  • Mercaptopurine
  • Pegloticase
  • Tegafur

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Aluminum Hydroxide
  • Cyclosporine
  • Phenprocoumon
  • Vidarabine
  • Warfarin

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Bone marrow problems or
  • Liver disease – Use with caution. May make these conditions worse.
  • Kidney disease – Use with caution. The effects may be increased because of slower removal of the medicine from the body.

Proper Use of Allopurinol (Oral Route)

Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance of side effects.

Take this medicine after meals to avoid stomach upset.

Take this medicine with plenty of liquids to help prevent kidney stones. Check with your doctor about the amount of liquid you or your child should drink each day.


The dose of this medicine will be different for different patients. Follow your doctor’s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):

    • For treatment of gout:

      • Adults – At first, 100 to 300 milligrams (mg) per day, taken once a day or in divided doses. Your doctor may adjust your dose as needed. However, the dose is usually not more than 800 mg per day.
      • Children – Use and dose must be determined by your doctor.
    • For treatment of high uric acid levels caused by cancer medicines:

      • Adults, teenagers, and children 11 years of age and older – 600 to 800 milligrams (mg) per day, taken in divided doses for 2 to 3 days.
      • Children 6 to 10 years of age – 300 mg per day, taken once a day for 2 to 3 days.
      • Children younger than 6 years of age – 150 mg per day, taken once a day for 2 to 3 days.
    • For treatment of kidney stones:

      • Adults – 200 to 300 milligrams (mg) per day, taken once a day or in divided doses. Your doctor may adjust your dose as needed. However, the dose is usually not more than 800 mg per day.
      • Children – Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.


It is very important that your doctor check your or your child’s progress at regular visits to make sure that this medicine is working properly. Blood and urine tests may be needed to check for unwanted effects.

When you start using this medicine, you may have more gout attacks. Keep using the medicine even if this happens. Your doctor may give you other medicines (eg, colchicine or pain medicines [NSAIDs]) to help prevent the gout attacks.

If you or your child develop a skin rash, hives, swelling of the lips or mouth, or any allergic reaction to this medicine, stop taking the medicine and call your doctor right away.

Check with your doctor right away if you or your child have pain or tenderness in the upper stomach; pale stools; dark urine; loss of appetite; nausea; unusual tiredness or weakness; or yellow eyes or skin. These could be symptoms of a serious liver problem.

This medicine may cause some people to become drowsy or less alert than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects of Allopurinol (Oral Route)

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

  1. Ankle, knee, or great toe joint pain
  2. joint stiffness or swelling
  3. rash
  4. rash with flat lesions or small raised lesions on the skin


  1. Abdominal or stomach pain
  2. agitation
  3. ammonia-like breath odor
  4. anxiety
  5. bleeding gums
  6. blistering, peeling, or loosening of the skin
  7. blood in the urine or stools
  8. bloody nose
  9. bloody or black, tarry stools
  10. blue or pale skin
  11. bruising
  12. changes in skin color
  13. chest pain or discomfort
  14. chest pain, possibly moving to the left arm, neck, or shoulder
  15. chills
  16. clay-colored stools
  17. cloudy urine
  18. coma
  19. confusion
  20. constipation
  21. cough or hoarseness
  22. coughing up blood
  23. cracks in the skin
  24. dark urine
  25. decreased urine output
  26. depression
  27. diarrhea
  28. difficulty with breathing
  29. dizziness
  30. drowsiness
  31. dry mouth
  32. feeling faint, dizzy, or lightheaded
  33. feeling of warmth or heat
  34. fever
  35. fever with or without chills
  36. flushing or redness of the skin, especially on the face and neck
  37. general feeling of discomfort or illness
  38. general feeling of tiredness or weakness
  39. headache
  40. hostility
  41. incoherent speech
  42. increased urination
  43. irritability
  44. itching
  45. joint or muscle pain
  46. large, flat, blue or purplish patches in the skin
  47. lethargy
  48. light-colored stools
  49. loss of appetite
  50. loss of heat from the body
  51. lower back or side pain
  52. metallic taste
  53. muscle twitching
  54. muscle weakness
  55. nausea or vomiting
  56. pain, tenderness, or swelling of the foot or leg
  57. painful or difficult urination
  58. pinpoint red or purple spots on the skin
  59. rapid weight gain
  60. rash
  61. red, irritated eyes
  62. red, swollen skin
  63. redness, soreness, or itching skin
  64. right upper abdominal or stomach pain and fullness
  65. scaly skin
  66. seizures
  67. severe stomach pain
  68. shortness of breath
  69. slow or irregular heartbeat
  70. sore throat
  71. sores, ulcers, or white spots on the lips or in the mouth
  72. sores, welting, or blisters
  73. stupor
  74. sweating
  75. swelling of the face, ankles, hands, or lower legs
  76. swollen or painful glands
  77. swollen, painful, or tender lymph glands in the neck, armpit, or groin
  78. thirst
  79. tightness in the chest
  80. unpleasant breath odor
  81. unusual bleeding or bruising
  82. unusual weight gain or loss
  83. vomiting of blood or material that looks like coffee grounds
  84. wheezing
  85. yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:


  1. Bad, unusual, or unpleasant (after) taste
  2. blindness
  3. blue-yellow color blindness
  4. blurred vision
  5. body aches or pain
  6. burning feeling in the chest or stomach
  7. burning, crawling, itching, numbness, prickling, “pins and needles”, or tingling feelings
  8. burning, dry, or itching eyes
  9. burning, numbness, tingling, or painful sensations
  10. change in taste
  11. change in vision
  12. congestion
  13. continuing ringing or buzzing or other unexplained noise in the ears
  14. decreased interest in sexual intercourse
  15. decreased vision
  16. difficulty with moving
  17. discharge or excessive tearing
  18. feeling of constant movement of self or surroundings
  19. hair loss or thinning of the hair
  20. hearing loss
  21. hives or welts
  22. impaired vision
  23. inability to have or keep an erection
  24. indigestion
  25. lack or loss of strength
  26. loss in sexual ability, desire, drive, or performance
  27. loss of appetite
  28. loss of memory
  29. multiple swollen and inflamed skin lesions
  30. muscle aching or cramping
  31. muscle pain or stiffness
  32. muscular pain, tenderness, wasting, or weakness
  33. noisy breathing
  34. problems with memory
  35. redness, pain, or swelling of the eye, eyelid, or inner lining of the eyelid
  36. runny nose
  37. sensation of spinning
  38. sensitivity to light
  39. sleepiness or unusual drowsiness
  40. sleeplessness
  41. sneezing
  42. stomach upset
  43. stuffy nose
  44. sweating
  45. swelling of the breasts or breast soreness in both females and males
  46. swelling of the salivary glands
  47. swelling or inflammation of the mouth
  48. swollen joints
  49. tearing
  50. tender, swollen glands in the neck
  51. tenderness in the stomach area
  52. throbbing pain
  53. tightness in the chest
  54. trouble getting pregnant
  55. trouble with sleeping
  56. trouble with swallowing
  57. unable to sleep
  58. unsteadiness or awkwardness
  59. voice changes
  60. weakness in the arms, hands, legs, or feet
  61. weight loss

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

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