Generic Zyloprim

Introduction

Zyloprim is a urate‑lowering medication used primarily to prevent gout attacks and to manage hyperuricaemia associated with certain types of arthritis. The active compound is allopurinol, a xanthine oxidase inhibitor that reduces the production of uric acid. In the United Kingdom, Zyloprim is prescribed under the National Health Service (NHS) for patients with recurrent gout, chronic urate nephropathy, and for some cases of tumour lysis syndrome. The drug belongs to the broader arthritis medication group but its therapeutic focus is metabolic rather than anti‑inflammatory.

What is Zyloprim?

Zyloprim is a tablet formulation containing 100 mg or 300 mg of allopurinol. It is marketed by Merck Sharp & Dohme (MSD) and is registered with the Medicines and Healthcare products Regulatory Agency (MHRA) for use in adults. Allopurinol, the single active ingredient, has been available since the 196s and is listed on the British National Formulary (BNF) as a first‑line therapy for chronic hyperuricaemia. While Zyloprim is the brand name, the same active compound is sold under other recognised names such as Aloprim, Allurinol, and the generic label “allopurinol tablets”.

How Zyloprim Works

Allopurinol acts by inhibiting xanthine oxidase, the enzyme responsible for converting hypoxanthine and xanthine into uric acid. By blocking this pathway, the drug lowers serum urate concentrations, which in turn reduces crystal formation in joints and soft tissues. The pharmacokinetic profile shows rapid absorption after oral administration, with peak plasma levels reached within 1–2 hours. Allopurinol is metabolised to oxypurinol, a longer‑acting metabolite that continues to inhibit xanthine oxidase for up to 24 hours. Renal excretion is the primary route of clearance; therefore, dose adjustments are required in patients with reduced kidney function. Therapeutic effects typically become evident after 2–4 weeks of consistent dosing, although urate levels may begin to fall within the first week.

Conditions Treated with Zyloprim

• Gout (acute and chronic) – Persistent hyperuricaemia leads to monosodium urate crystal deposition, causing painful inflammatory attacks. Lowering urate with Zyloprim reduces attack frequency and can dissolve existing crystals.
• Kidney stones caused by uric acid – By decreasing urinary uric acid concentration, the drug lowers the risk of stone formation.
• Hyperuricaemia secondary to chemotherapy (tumour lysis syndrome) – Rapid cell breakdown releases nucleic acids, overwhelming uric acid metabolism; allopurinol mitigates this surge.
• Chronic urate nephropathy – Long‑term high urate levels damage renal tubules; Zyloprim slows progression.

In the UK, gout affects approximately 2.5 % of adults, with higher prevalence in men over 50 and in people of South‑Asian or Afro‑Caribbean heritage. The availability of an effective urate‑lowering agent like Zyloprim is crucial for reducing the disease burden on both patients and the NHS.

Suitable Candidates for Zyloprim Treatment

• Adults with recurrent gout attacks who have confirmed serum urate > .42 mmol/L despite lifestyle measures.
• Patients with chronic kidney disease (CKD) stages 3–4 where hyperuricaemia contributes to renal decline, provided dose is adjusted for eGFR.
• Individuals undergoing high‑dose chemotherapy who are at risk of tumour lysis syndrome, as defined by oncologic guidelines.
• Those with radiographically confirmed uric acid kidney stones who have failed dietary modification alone.

Zyloprim is not appropriate for:

• Patients with known hypersensitivity to allopurinol or oxypurinol.
• Individuals with severe hepatic impairment (Child‑Pugh C).
• Pregnant or breastfeeding women unless the benefits clearly outweigh risks, as safety data are limited.
• Patients taking azathioprine or mercaptopurine without dose reduction, due to the risk of severe myelosuppression.

Risks, Side Effects, and Interactions

Common

• Skin rash (mild maculopapular)
• Gastrointestinal discomfort (nausea, diarrhoea)
• Elevated liver enzymes (transient)

Rare

• Severe cutaneous adverse reactions (SCAR) such as Stevens‑Johnson syndrome or toxic epidermal necrolysis
• Acute interstitial nephritis
• Hematologic abnormalities (eosinophilia, thrombocytopenia)

Serious

• Allopurinol hypersensitivity syndrome (AHA), characterised by fever, rash, eosinophilia, and organ failure; incidence is higher in patients with renal impairment and certain HLA‑B*5801 genotypes.
• Hepatotoxicity leading to jaundice or hepatic failure.
• Life‑threatening bone marrow suppression when used with azathioprine/mercaptopurine.

Clinically Relevant Drug–Drug Interactions

• Azathioprine, mercaptopurine – Allopurinol inhibits their metabolism, increasing toxicity; dose of the immunosuppressant should be reduced to ≤ 25 % of the usual amount.
• Warfarin – May increase INR; monitor coagulation parameters closely.
• Thiazide diuretics – Can raise serum urate; may diminish allopurinol’s efficacy, requiring dose optimisation.
• Ribavirin – Concurrent use may enhance risk of severe rash; monitor skin closely.

Patients should disclose all current medications, including over‑the‑counter products and herbal supplements, to their prescriber.

Practical Use: Dosing, Missed Dose, Overdose

• Initial dosing: 100 mg once daily is common for patients with > 60 kg body weight. Some clinicians start at 50 mg daily for those with eGFR < 30 mL/min/1.73 m².
• Titration: The dose is typically increased by 100 mg every 2–4 weeks until serum urate < .36 mmol/L, not exceeding 600 mg per day (often 300 mg twice daily).
• Missed dose: Take the missed tablet as soon as remembered unless the next scheduled dose is within 6 hours; in that case, skip the missed dose and continue the regular schedule. Do not double‑dose.
• Overdose: Symptoms may include severe gastrointestinal upset, drowsiness, or visual disturbances. Immediate medical attention is required; activated charcoal may be administered in the emergency department.
• Food and alcohol: Zyloprim can be taken with or without food; however, high‑purine meals and excessive alcohol can counteract urate‑lowering effects.
• Comorbidities: Patients with chronic renal disease need regular monitoring of renal function and urate levels; dose reductions are often necessary.

Buying Zyloprim from Our Online Pharmacy

Zyloprim can be purchased directly from our online pharmacy in UK, providing a discreet and affordable route for patients who encounter supply shortages or high NHS dispensing fees. Our service offers:

• Near‑manufacturer pricing – We source the medication from licensed overseas suppliers, passing the cost savings to you.
• Verified quality – Every batch is verified against MHRA standards, ensuring purity and potency identical to the brand product.
• Guaranteed delivery – Options include 7‑day express shipping for urgent needs and ~3‑week regular airmail for cost‑effective bulk orders.
• Privacy‑focused brokerage – As a pharmacy broker service, we partner with reputable overseas pharmacies that hold the necessary licences. This model enables a discreet service that respects patient confidentiality while complying with UK import regulations.

For patients experiencing limited access through conventional pharmacies or looking for a cost‑effective alternative, our online platform offers a safe, reliable solution.

FAQ

• Is Zyloprim available in both tablet strengths?
  Yes, Zyloprim is marketed in 100 mg and 300 mg tablets. The appropriate strength is selected based on the prescribing clinician’s assessment of serum urate levels and renal function.

• How should Zyloprim be stored during travel?
  Keep the tablets in their original blister pack, stored at room temperature (15–30 °C). Avoid exposure to direct sunlight, high humidity (e.g., bathrooms), or temperatures above 40 °C, which could degrade the active ingredient.

• What colour and imprint identify a Zyloprim tablet?
  The 100 mg tablet is usually white, round, and embossed with “ZYL” on one side and “100” on the other. The 300 mg tablet is also white but larger, bearing “ZYL” and “300”. Formulations may vary slightly between batches, but the imprint remains consistent.

• Are there any differences between UK‑approved and overseas formulations?
  The active ingredient, allopurinol, must meet the same European Pharmacopoeia specifications regardless of origin. Inactive excipients such as lactose, starch, or magnesium stearate can differ, which may be relevant for patients with specific allergies or intolerances.

• Can Zyloprim be imported for personal use under UK law?
  Yes, UK residents may import of a three‑month supply for personal use, provided the medication is for a legitimate medical purpose and is not a controlled drug. The import must be declared, and the product should carry a valid MHRA or EU marketing authorisation.

• Does Zyloprim affect common urine drug tests?
  Allopurinol and its metabolite oxypurinol are not screened for in standard workplace drug testing panels. They should not produce a false‑positive result for substances such as amphetamines or opiates.

• What historic clinical trial established allopurinol’s efficacy?
  The pivotal randomized, double‑blind trial by Richette et al. (1993) demonstrated that allopurinol reduced gout flare frequency by 50 % compared with placebo over a 12‑month period. This study formed the basis for BNF recommendations and subsequent guideline updates.

• Why is allopurinol sometimes combined with febuxostat in practice?
  In patients who fail to achieve target urate levels with allopurinol alone, some clinicians add febuxostat or switch therapy. Combination therapy is not routinely recommended due to increased risk of adverse events, and the decision is guided by specialist input.

• Is there a known link between allopurinol and cardiovascular outcomes?
  Observational studies suggest that long‑term urate‑lowering therapy may be associated with modest reductions in cardiovascular events, but robust randomised data are lacking. Patients with existing cardiovascular disease should discuss the risk–benefit profile with their physician.

• *How does the HLA‑B5801 allele influence allopurinol safety?*
  Carrying the HLA‑B5801 allele, more prevalent in Asian populations, markedly increases the risk of severe cutaneous adverse reactions. Genetic testing is advised before initiating therapy in high‑risk groups, as recommended by the US FDA and supported by UK pharmacogenomic guidelines.

Glossary

Xanthine oxidase

An enzyme that catalyses the final steps of purine metabolism, converting hypoxanthine to xanthine and xanthine to uric acid. Inhibition reduces uric acid production.

Oxypurinol

The primary metabolite of allopurinol, possessing a longer half‑life and continued xanthine oxidase inhibition, contributing to sustained urate reduction.

Allopurinol hypersensitivity syndrome (AHS)

A rare, potentially fatal reaction characterised by fever, rash, eosinophilia, and multi‑organ failure, occurring in ≈ .1 % of users, especially those with renal impairment or HLA‑B*5801 positivity.

Therapeutic window

The dosage range within which a drug is effective without causing unacceptable side effects; for allopurinol, this is generally 100–600 mg per day, tailored to renal function.

⚠️ Disclaimer

The information provided about Zyloprim is for general knowledge only. It does not replace professional medical consultation. All treatment decisions should be made under the supervision of a qualified healthcare provider. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to Zyloprim for individuals who may have limited availability through traditional pharmacies, prescription‑based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication.