Allopurinol is a drug used to treat multiple sclerosis (MS). It was first developed in the 1970’s. The main goal of Allopurinol is to reduce the symptoms associated with MS such as fatigue, pain, numbness, tingling and loss of balance. It helps prevent relapses and prevents permanent disability from MS. The side effects are not severe or life threatening but they do occur occasionally. The most common side effect is weight gain. Other possible side effects include: dizziness, nausea, headache, dry mouth, constipation and insomnia. There have been reports of sudden death due to overdose of Allopurinol.
The FDA approved Allopurinol in 1996 for use in patients with relapsing forms of multiple sclerosis (MS) whose disease activity had stabilized after two years of treatment with other drugs. In 2004, the FDA approved Allopurinol for use in adults with relapsing forms of MS who were no longer responding to interferon beta. The drug is available only through prescription.
Allopurinol tablets contain 300 milligrams of allopurinol hydrochloride and are white, round and slightly rounded at one end. They are approximately 1/4 inch long and weigh 0.5 ounce each when crushed into a powder form. Allopurinol tablets are manufactured by Pfizer, Inc. Allopurinol is available in 0.5mg, 100mg and 300mg tablet strengths.
If Allopurinol proves ineffective or causes severe side effects, the physician may try a different dosage or a different medication altogether. If your physician has prescribed a new medication while you are taking Allopurinol, be sure to tell your doctor before you stop taking any of your current medications.
Stop taking Allopurinol and see your physician immediately if you experience any sudden or unexplained weight gain, swelling of the extremities or ankle area, shortness of breath or difficulty breathing, chest pain, heart palpitations, or any other unusual physical symptom. Be sure to mention any medication you are currently taking, including non-prescription and herbal medications.
Do not take Allopurinol if you:
Are allergic to any of the ingredients in Allopurinol tablets.
Are allergic to allopurinol or related drugs such as Zyloprim, Lopurin, or the medication, Furoxone.
Have a history of bone marrow depression.
Have low levels of potassium or magnesium in your blood.
Have kidney dysfunction or kidney failure.
Have uncontrolled high blood pressure.
Are experiencing an irregular heart beat.
Are experiencing liver disease.
Are a female who is pregnant, tries to become pregnant, or breastfeeding.
Allopurinol can make birth control pills less effective. You may wish to use a different type of non-hormonal birth control (such as a condoms or an IUD) while taking this medication and for three months after your last dose.
are allergic to any other medications.
Taking Allopurinol may make you more likely to experience severe allergic reactions (anaphylaxis). If you think you are having a serious allergic reaction, call your doctor or 911 immediately. Symptoms may include: swelling of the face, mouth, lips or throat; difficulty breathing; hives; or shock.
Common side effects of Allopurinol may include:
Diarrhea, nausea, vomiting, upset stomach, loss of appetite, infection (fever, sore throat), headache, dizziness, drowsiness.
Stop taking Allopurinol and seek immediate medical attention if you experience an allergic reaction (see above). Symptoms may include: rash, itching, difficulty breathing, tightness in the chest, swelling of the mouth, face, lips or tongue.
This is not a complete list of potential side effects. If you experience any discomfort not listed above, or other health concerns, contact your physician immediately.
What exactly is Allopurinol?
Allopurinol is the medication that helps to keep your uric acid levels in a healthy range. Uric Acid is a natural by-product of the metabolic process that can cause painful and even lethal crystals to form and settle in our joints, especially in the large joints, such as the knee. Allopurinol helps to prevent this from occurring.
How do I know if I need Allopurinol?
You may require Allopurinol if your doctor has recommended it as a treatment for your condition. You may also be required to take an initial dosage adjustment period before the medication is fully effective.
How should I take Allopurinol?
Allopurinol comes in tablet form and is taken once daily with or without food. It is advised that you take the medication at the same time every day to maintain consistency. Allopurinol may be taken with or without food.
What if I forget to take a dose of Allopurinol?
If you forget to take your medication, take it as soon as you remember. If it is almost time for your next dose, skip the one you missed and go back to your regular dosing schedule. Do not take a double dose.
What if I overdose on Allopurinol?
If you happen to take too much Allopurinol you may experience side effects such as diarrhea, nausea, vomiting, upset stomach, loss of appetite, infection (fever, sore throat), headache, dizziness, drowsiness. If you experience any of these symptoms seek immediate medical attention.
What precautions should I follow when taking Allopurinol?
If you are scheduled for any lab tests, inform the physician or technician immediately before the procedure that you are taking Allopurinol. The levels of apple cider vinegar in your blood may interfere with the outcome of the test. Allopurinol may also make certain drugs less effective. Be sure to tell all health professionals providing care that you are taking Allopurinol.
What medications should I avoid while taking Allopurinol?
Before taking Allopurinol you should let your physician know if you are taking any of the following: Aminopyrine, cimetidine, phenazone, pizotifen, probenecid, propanolol, thiazide and triamterene.
Also let your doctor know if you consume more than 3 alcohol containing drinks a day. Alcohol may worsen the side effects of Allopurinol.
Is there anything I should particularly avoid while taking Allopurinol?
Allopurinol can cause drowsiness and affect concentration, do not drive or operate heavy machinery until you know how the medication affects you. Alcohol may worsen the drowsiness caused by this medication. Refrain from drinking alcohol while taking Allopurinol.
You should also avoid getting too hot, exposure to high temperatures may cause your body’s core temperature to increase which may worsen the effects of the medication.
What are the possible side effects of Allopurinol?
Allopurinol is generally well tolerated by most patients however common side effects include: allergic reaction, anemia, back pain, bloody or tarry stools, bone pain, breathing difficulties, chest pain, cold hands and feet, constipation, coughing up blood, decreased urination, depression, diarrhea, difficulty swallowing, dizziness, dry mouth, excessive hunger, facial flushing, fever, fungal infection (vaginal), fungal skin infection (ringworm), gas (flatulence), general feeling of illness, hair loss, headache, hives, hoarseness, indigestion, joint pain, lightheadedness when getting up, ligament pain, loss of appetite, low white blood cell count, mouth soreness, muscle aches and pains, numbness or tingling of the arms and legs, paranoia, pounding heartbeat, rapid weight gain, rash, ringing in the ears, runny nose, shortness of breath, sinus pain or congestion, skin itching or discoloration, slow healing of cuts and sores, sore throat, stomach bloating and discomfort, stomach pain, stools with blood or blood clots, swollen lymph nodes in neck, underarms, and groin, tendon inflammation (elbow, wrist, and thumb), tightness in the chest, tingling of extremities, tremor, trouble sleeping, unexplained weight gain, unusual bleeding or bruising, vision problems.
As with all drugs, some people may experience side effects other than those listed. If you notice any side effects not listed above, contact your doctor or pharmacist.
If you experience warning signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, dizziness, or swelling of the lips, mouth, or tongue) after taking this medication, seek immediate medical attention.
This medication may cause your skin to be extra sensitive to the sun. Limit your time in the sun. In addition, avoid tanning booths and do not use sunscreen (clothes or otherwise) while taking this medication due to risk of serious skin reactions.
Where can I get more information?
Your pharmacist has additional information about Allopurinol written for health professionals that you may read.
Sources & references used in this article:
Bioavailability of allopurinol oral and rectal dosage forms by SL Chang, WG Kramer, S Feldman… – American journal of …, 1981 – academic.oup.com
Allopurinol kinetics and bioavailability by SJ Appelbaum, M Mayersohn, RT Dorr… – Cancer Chemotherapy …, 1982 – Springer
X-linked recessive (Duchenne) muscular dystrophy (DMD) and purine metabolism: effects of oral allopurinol and adenylate by WHS Thomson, I Smith – Metabolism, 1978 – Elsevier
Stability of acetazolamide, allopurinol, azathioprine, clonazepam, and flucytosine in extemporaneously compounded oral liquids by LV Allen Jr, MA Erickson III – American journal of health-system …, 1996 – academic.oup.com