Zyloprim, with the active ingredient allopurinol, is a xanthine oxidase inhibitor prescribed for the long-term management of gout and conditions marked by elevated uric acid levels, such as hyperuricemia. It functions by reducing the production of uric acid in the body, thereby preventing the formation of urate crystals that cause painful gout attacks and joint damage. This medication is a cornerstone in preventive therapy, aiding in the reduction of both acute flare frequency and the risk of chronic arthropathy and tophi development. Proper use under medical supervision can significantly improve quality of life for patients suffering from these metabolic disorders.

Features

• Active ingredient: Allopurinol 100 mg and 300 mg tablets
• Drug class: Xanthine oxidase inhibitor
• Administration: Oral tablet
• Available in generic and brand formulations
• Requires prescription
• Manufactured under strict pharmaceutical quality standards

Benefits

• Prevents the formation of new uric acid crystals in joints and tissues
• Reduces the frequency and severity of acute gout attacks over time
• Helps resolve existing tophi (urate crystal deposits) with prolonged therapy
• Lowers serum uric acid levels to target ranges (typically below 6 mg/dL)
• Minimizes risk of chronic gouty arthropathy and joint destruction
• May prevent uric acid nephrolithiasis (kidney stones)

Common use

Zyloprim (allopurinol) is primarily indicated for the management of:

• Chronic gout and gouty arthritis
• Hyperuricemia secondary to malignancies or cancer chemotherapy
• Recurrent uric acid stone formation
• Hyperuricemia associated with Lesch-Nyhan syndrome

It is not intended for the treatment of acute gout attacks but rather for prophylaxis and long-term control. Treatment is typically initiated after acute inflammation has subsided.

Dosage and direction

Dosage must be individualized based on serum uric acid levels, renal function, and therapeutic response. The typical adult dosage ranges from 200-300 mg daily for mild gout, to 400-600 mg daily for moderate to severe gout, divided into single or multiple doses. For patients with renal impairment, dosage reduction is necessary. The initial dose is usually 100 mg daily, gradually increased by 100 mg weekly until desired uric acid level is achieved. Maximum daily dose should not exceed 800 mg. Tablets should be taken with a full glass of water after meals to minimize gastric upset. Consistent daily administration is crucial for maintaining therapeutic uric acid levels.

Precautions

• Periodic monitoring of liver function, renal function, and complete blood counts is recommended during therapy
• Adequate hydration (2-3 liters of fluid daily) is essential to prevent xanthine crystalluria
• Initiation of therapy may precipitate acute gout attacks; concurrent prophylactic NSAID or colchicine therapy is often recommended during the first 3-6 months
• Caution required in patients with hepatic impairment or history of alcohol abuse
• Skin rash occurs in approximately 2% of patients and may indicate hypersensitivity; discontinuation is advised if rash develops
• Not recommended during asymptomatic hyperuricemia unless specifically indicated

Contraindications

• Hypersensitivity to allopurinol or any component of the formulation
• Patients who have experienced a severe reaction to allopurinol previously (including Stevens-Johnson syndrome, toxic epidermal necrolysis)
• Concurrent therapy with didanosine (contraindicated due to increased toxicity risk)
• Not recommended during acute gout attacks (may prolong acute phase)

Possible side effect

Common side effects (≥1%):

• Skin rash (discontinue immediately if rash appears)
• Nausea, vomiting, diarrhea
• Drowsiness, headache
• Elevated liver enzymes

Less common but serious side effects:

• Severe hypersensitivity reactions (including Stevens-Johnson syndrome, toxic epidermal necrolysis)
• Hepatitis, hepatotoxicity
• Bone marrow suppression (leukopenia, thrombocytopenia, agranulocytosis)
• Vasculitis, peripheral neuritis
• Renal impairment, acute renal failure
• Alopecia, taste perversion

Drug interaction

• Azathioprine/6-mercaptopurine: Allopurinol inhibits their metabolism, requiring 25-33% of usual dose
• Warfarin: Enhanced anticoagulant effect; monitor INR closely
• Ampicillin/amoxicillin: Increased incidence of skin rash
• Diuretics: May increase risk of hypersensitivity reactions
• Theophylline: Increased serum concentrations
• ACE inhibitors: Increased risk of hypersensitivity reactions
• Cyclophosphamide: Enhanced bone marrow toxicity
• Didanosine: Contraindicated due to increased toxicity

Missed dose

If a dose is missed, take it as soon as remembered unless it is almost time for the next scheduled dose. Do not double the dose to make up for a missed one. Maintaining consistent blood levels is important for optimal uric acid control, but occasional missed doses are unlikely to significantly impact long-term management. Establish a routine (e.g., taking with a meal) to improve adherence.

Overdose

Symptoms may include nausea, vomiting, diarrhea, dizziness, and renal impairment. Massive overdose may cause hepatotoxicity and bone marrow suppression. There is no specific antidote; treatment is supportive and symptomatic. Gastric lavage may be considered if presented early. Hemodialysis may be effective in removing allopurinol and oxipurinol (its active metabolite). Maintain adequate hydration and monitor renal, hepatic, and hematologic parameters closely.

Storage

Store at controlled room temperature (20-25°C or 68-77°F). Keep container tightly closed and protect from moisture and light. Keep out of reach of children and pets. Do not use after expiration date printed on packaging. Do not transfer tablets to other containers that may not provide adequate protection from light and moisture.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Zyloprim (allopurinol) is a prescription medication that should only be used under the supervision of a qualified healthcare professional. Dosage, indications, and precautions may vary based on individual patient factors. Always consult with a physician for proper diagnosis and treatment recommendations. Do not initiate or discontinue medication without medical guidance.

Reviews

“After struggling with frequent gout attacks for years, Zyloprim has given me my life back. The first few months required patience as we adjusted the dosage, but now I’ve been attack-free for over two years. Regular blood tests are essential, but the freedom from pain is worth it.” - James R., 58

“As an oncologist, I frequently prescribe allopurinol for tumor lysis syndrome prophylaxis. When dosed appropriately with renal adjustment, it’s highly effective at preventing hyperuricemic complications during chemotherapy. The key is starting before chemotherapy initiation and monitoring uric acid levels closely.” - Dr. Elena M., Oncologist

“I experienced a mild rash when first starting Zyloprim, which resolved after discontinuation. My rheumatologist successfully rechallenged with a lower initial dose and slower titration. Now tolerating it well with excellent uric acid control. Important to work closely with your doctor through any initial reactions.” - Michael T., 64