1. Disclaimer
This page is intended for general educational and informational purposes only. It is not a substitute for the current Egyptian package leaflet, prescribing information, or advice from a qualified healthcare professional. Product availability, manufacturer/marketing-authorisation arrangements, formulations, excipients, indications, and regulatory information may change. Always verify the current locally approved product information before use.
We do not guarantee the accuracy, currency or completeness of information regarding medications or medical products, and official sources should be verified before making any decisions. By using this blog, you agree to assume personal responsibility for relying on the information provided.
2. Summary
Zyloric contains allopurinol, a xanthine oxidase inhibitor that reduces the formation of uric acid. It is primarily used for long-term management of conditions associated with urate/uric-acid accumulation, including gout and certain uric-acid stone disorders, and for prevention or management of hyperuricaemia associated with high cell turnover in selected patients.
Allopurinol is not intended to provide immediate relief of an acute gout attack. Treatment is generally initiated at a low dose and adjusted according to clinical response and serum urate, with particular care in renal impairment. (Medicines.org.uk)
3. Brand Name
ZYLORIC™
The identified Egyptian-market presentations are:
- Zyloric 100 mg – 30 tablets
- Zyloric 300 mg – 30 tablets
The brand name Zyloric is associated with allopurinol. (Vezeeta)
4. Category
Therapeutic category: Antigout / urate-lowering therapy
Pharmacological class: Xanthine oxidase inhibitor
ATC classification: M04AA01 – Allopurinol. (Medicines.org.uk)
5. Active Ingredient
Allopurinol
Each tablet contains either:
- Allopurinol 100 mg, or
- Allopurinol 300 mg
Allopurinol is converted to the active metabolite oxypurinol (alloxanthine), which contributes substantially to the prolonged inhibition of xanthine oxidase. (Medicines.org.uk)
6. Pharmaceutical Form & Strength
Pharmaceutical form: Oral tablet
Strengths identified:
- 100 mg allopurinol/tablet
- 300 mg allopurinol/tablet
Current product information describes Zyloric as tablets. The detailed physical characteristics can vary between markets and manufacturing versions, so the locally supplied pack/leaflet should be checked for exact tablet appearance and excipients. (Medicines.org.uk)
Egyptian pack size identified: 30 tablets per box for both 100 mg and 300 mg presentations. (Vezeeta)
7. Manufacturer & Marketing Authorization Holder
Egyptian-market manufacturer: Current Egyptian pharmacy listings identify GlaxoSmithKline (GSK) as the manufacturer of Zyloric 100 mg and 300 mg. Historical Egyptian product information also identifies GlaxoSmithKline S.A.E., El Salam City, Cairo, Egypt, under licence from the GlaxoSmithKline group of companies. (Vezeeta)
Marketing Authorization Holder: The currently applicable Egyptian MAH could not be independently verified from a current Egyptian regulatory document available in the searched sources. Therefore, it should not be stated definitively that the Egyptian MAH is GSK without checking the current Egyptian registered-product record or package leaflet.
This distinction is important because Zyloric's manufacturer/MAH arrangements differ between markets; for example, the current UK SmPC identifies Aspen for Zyloric there. (Medicines.org.uk)
8. Mechanism of Action
Allopurinol inhibits xanthine oxidase, the enzyme involved in the conversion of:
Hypoxanthine → Xanthine → Uric acid
By reducing uric-acid production, allopurinol lowers circulating and urinary urate concentrations.
Its major metabolite, oxypurinol, also inhibits xanthine oxidase and has a substantially longer elimination half-life than allopurinol, contributing to sustained enzyme inhibition. Allopurinol may additionally reduce de-novo purine synthesis in some hyperuricaemic patients through feedback effects on purine metabolism. (Medicines.org.uk)
9. Spectrum of Activity
Not applicable in the antimicrobial sense.
Zyloric is not an antibacterial, antiviral, antifungal, or antiparasitic drug, so it does not have a conventional antimicrobial "spectrum of activity."
Its pharmacological effect is metabolic: inhibition of xanthine oxidase and reduction of uric-acid production.
10. Pharmacokinetics
Absorption
Allopurinol is orally absorbed, principally from the upper gastrointestinal tract. Peak plasma concentrations of unchanged allopurinol occur relatively soon after administration, while oxypurinol reaches peak concentrations later and persists considerably longer. (Medicines.org.uk)
Distribution
Allopurinol is only minimally bound to plasma proteins. Its apparent volume of distribution indicates substantial tissue distribution. (Medicines.org.uk)
Metabolism
Allopurinol is metabolised principally to oxypurinol by xanthine oxidase and aldehyde oxidase. Other metabolites include allopurinol-riboside and oxypurinol-7-riboside. (Medicines.org.uk)
Elimination
Less than 10% of unchanged allopurinol is excreted in urine. Oxypurinol is eliminated predominantly through the kidneys and undergoes tubular reabsorption, accounting in part for its prolonged elimination. (Medicines.org.uk)
Half-life
Allopurinol has a short plasma half-life, approximately 0.5–1.5 hours, whereas oxypurinol has a much longer half-life, with reported values varying according to renal function and study conditions. (Medicines.org.uk)
Renal impairment substantially reduces oxypurinol clearance and can result in accumulation, which is a major reason for cautious dosing in patients with impaired kidney function.
11. Indications
Zyloric/allopurinol is used to reduce urate/uric-acid formation in conditions in which urate deposition has occurred or represents a predictable clinical risk.
Recognised indications in current Zyloric product information include:
- Gout and chronic urate deposition, including gouty arthritis and tophi
- Uric-acid nephrolithiasis
- Acute uric-acid nephropathy in appropriate clinical settings
- Hyperuricaemia associated with neoplastic disease or high cell turnover, including situations related to cytotoxic treatment
- Selected inherited enzyme disorders causing excessive urate production, including Lesch–Nyhan syndrome
- 2,8-dihydroxyadenine (2,8-DHA) renal stones associated with adenine phosphoribosyltransferase deficiency
- Selected recurrent mixed calcium-oxalate renal stones associated with hyperuricosuria when appropriate non-drug measures have failed. (Medicines.org.uk)
Asymptomatic hyperuricaemia alone is not automatically an indication for pharmacological treatment; the underlying cause and overall clinical context must be considered.
12. Administration
Zyloric is administered orally.
It is commonly taken once daily, although divided administration may be used when clinically appropriate, particularly with higher total daily doses or gastrointestinal intolerance.
Taking the medicine after food may improve gastrointestinal tolerability. Adequate fluid intake is generally important in patients being treated for urate-related urinary disorders, subject to the individual's clinical condition.
Allopurinol should be introduced at a low dose and titrated according to the clinical situation and serum urate response rather than treating the tablet strength itself as a fixed universal dose. Renal function is particularly important when determining an appropriate regimen. (Medicines.org.uk)
13. Method of Preparation
No preparation or reconstitution is required.
Zyloric is supplied as a ready-to-use oral tablet.
The tablet should be taken according to the current locally approved instructions. It should not be crushed, split, or otherwise modified unless the current product information specifically permits this for the particular presentation.
14. Contraindications
The principal contraindication is:
- Known hypersensitivity to allopurinol or to any component of the formulation. (Medicines.org.uk)
The current product information should always be checked for formulation-specific excipients and any additional locally applicable contraindications.
15. Warnings & Precautions
Serious hypersensitivity and skin reactions
Allopurinol can rarely cause severe, potentially life-threatening hypersensitivity reactions, including severe cutaneous adverse reactions such as Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other systemic hypersensitivity syndromes.
Allopurinol should be stopped immediately if a significant skin rash or other evidence of hypersensitivity develops, and urgent medical assessment may be required. Re-exposure after a serious hypersensitivity reaction should generally be avoided. (Medicines.org.uk)
Renal impairment
Allopurinol and especially oxypurinol can accumulate when renal function is impaired. Dose selection therefore requires particular caution in patients with reduced kidney function. (Medicines.org.uk)
Hepatic impairment
Patients with hepatic impairment may require cautious use and clinical monitoring.
Acute gout
Allopurinol is a long-term urate-lowering treatment, not an analgesic treatment for an acute gout attack. Initiation of urate-lowering therapy can precipitate gout flares, particularly during the early treatment period. Appropriate anti-inflammatory flare prophylaxis may therefore be considered according to the patient's clinical circumstances.
If a gout flare occurs in someone already established on allopurinol, the urate-lowering treatment is generally not routinely discontinued solely because of the flare.
Cardiovascular/renal comorbidity
Patients receiving diuretics, ACE inhibitors, or treatment for hypertension/heart failure may have concomitant renal impairment and may require additional caution. (HPRA Assets)
Fluid intake
Adequate hydration is particularly relevant in conditions involving high urate production or urinary urate/uric-acid stone formation, when medically appropriate.
16. Drug Interactions
Clinically important interactions include:
Azathioprine and 6-mercaptopurine
Allopurinol inhibits their metabolism through xanthine oxidase inhibition and can markedly increase their exposure and toxicity. Their usual doses generally require substantial reduction when combined, under specialist supervision. (HPRA Assets)
Warfarin and other coumarin anticoagulants
Allopurinol may increase anticoagulant effects in some patients; appropriate monitoring may be required. (Medicines.org.uk)
Ampicillin / amoxicillin
Concurrent treatment has been associated with an increased frequency of skin rash. (HPRA Assets)
Diuretics
Particular caution may be required, especially when renal impairment is present.
Probenecid and salicylates
These can alter oxypurinol renal elimination and may influence allopurinol's urate-lowering effect. The clinical significance depends on the individual situation. (Medicines.org.uk)
Chlorpropamide
In patients with impaired renal function, concurrent use may increase the risk of prolonged hypoglycaemic activity. (Medicines.org.uk)
Phenytoin
Allopurinol may affect phenytoin metabolism, although the clinical significance is uncertain. (Medicines.org.uk)
Theophylline
Allopurinol may inhibit theophylline metabolism in some circumstances; monitoring may be appropriate when therapy is initiated or increased. (Medicines.org.uk)
Cytotoxic drugs
Interactions with cytotoxic therapy may increase the risk of haematological toxicity in some settings, although the evidence is not uniform across all cytotoxic agents. (Medicines.org.uk)
Cyclosporin
Cyclosporin concentrations may increase during concomitant treatment, potentially increasing toxicity risk. (HPRA Assets)
Didanosine
Allopurinol can substantially increase didanosine exposure; concomitant use may require dose adjustment and specialist monitoring. (Medicines.org.uk)
Patients should provide their healthcare professional with a complete list of prescription medicines, OTC medicines, and supplements before starting allopurinol.
17. Side Effects
Adverse effects range from mild gastrointestinal symptoms and skin rash to rare but serious hypersensitivity reactions.
Commonly reported
- Skin rash
- Nausea
- Vomiting
Taking the medicine after food may improve gastrointestinal tolerability. (Medicines.org.uk)
Other reported reactions
Reported adverse reactions include:
- Hypersensitivity reactions
- Abnormal liver-function tests
- Hepatitis
- Gastrointestinal disturbances
- Headache, dizziness, somnolence, paraesthesia or ataxia
- Haematological abnormalities such as thrombocytopenia, agranulocytosis, or aplastic anaemia
- Angioedema
- Renal or urinary abnormalities
- Oedema, malaise, asthenia, or fever
- Rare severe cutaneous reactions including SJS/TEN. (Medicines.org.uk)
The exact frequency of individual reactions varies among sources and populations. Older Zyloric documentation explicitly noted that reliable modern incidence data were unavailable for some adverse reactions; therefore unsupported numerical frequencies should not be presented as current precise incidence estimates.
Any new widespread rash, blistering, mucosal lesions, fever, facial swelling, or other symptoms suggesting serious hypersensitivity require immediate medical assessment.
18. Use in Special Populations
Pregnancy
Available human evidence has not established a clear pattern of major fetal harm, but the evidence base is limited. Allopurinol should be used during pregnancy only when clinically justified and after professional assessment of benefits and risks. (HPRA Assets)
Breastfeeding
Allopurinol and oxypurinol are excreted into human breast milk. Current patient information advises discussing breastfeeding with a healthcare professional before use; some product information does not recommend allopurinol during breastfeeding. (HPRA Assets)
Children
Use in children is generally limited to selected situations, such as certain malignant conditions or inherited enzyme disorders, and requires specialist supervision. (Medicines.org.uk)
Older adults
Dose selection should take renal function into account. Age itself is less important than the patient's kidney function and overall clinical status.
Renal impairment
Renal impairment is particularly important because oxypurinol clearance is substantially reduced. Dose adjustment and careful monitoring are required. (Medicines.org.uk)
Hepatic impairment
Cautious use and appropriate clinical monitoring are recommended.
19. Storage Conditions
The historical and currently indexed Zyloric product information specifies:
Store below 25°C and keep dry. (Doctor M Pharmacy)
Keep the medicine in its original packaging and out of the reach of children.
Because storage requirements can change between formulations and markets, the temperature and storage instructions printed on the current Egyptian package should take precedence.
20. Additional Sections
Driving and operating machinery
Allopurinol may cause dizziness, drowsiness, or coordination problems in some patients. Patients should determine how the medicine affects them before driving or operating machinery. (HPRA Assets)
Overdose
Large allopurinol ingestions have been reported. Possible manifestations include gastrointestinal symptoms such as nausea, vomiting, and diarrhoea, with management primarily supportive and focused on appropriate clinical assessment and elimination of the drug/metabolites. Haemodialysis may be considered in severe circumstances when clinically appropriate. (Futpmp)
Important treatment principle
Allopurinol lowers uric-acid production; it does not directly dissolve an acute gout attack or provide immediate analgesia.
Product status in Egypt
The searched Egyptian pharmacy sources currently list both Zyloric 100 mg/30 tablets and Zyloric 300 mg/30 tablets. Some current listings show the products as out of stock at the time of crawling, which reflects availability at those individual retailers rather than proof of nationwide discontinuation. (Vezeeta)
21. Frequently Asked Questions (FAQ)
What is Zyloric?
Zyloric is a brand of allopurinol, a xanthine oxidase inhibitor used to reduce uric-acid production.
What is Zyloric 100 mg used for?
It contains 100 mg of allopurinol and may be used as part of urate-lowering treatment when clinically indicated. The appropriate dose depends on the patient's condition and response.
What is Zyloric 300 mg used for?
It contains 300 mg of allopurinol and is used for the same general therapeutic purposes as the 100-mg presentation; the appropriate dose is individualized.
Is Zyloric used during an acute gout attack?
Allopurinol is not an acute pain-relief treatment. Starting urate-lowering therapy during an acute flare requires clinical judgment, while patients already established on allopurinol generally do not stop it solely because a flare occurs.
Should Zyloric be taken after food?
Taking it after food can improve gastrointestinal tolerability.
Is Zyloric safe for people with kidney disease?
It can be used in some patients with renal impairment, but dose selection requires particular caution because oxypurinol is predominantly eliminated by the kidneys.
Can Zyloric cause a skin rash?
Yes. Rash is a recognised adverse effect. Because rash can occasionally be the first sign of a serious hypersensitivity reaction, a new rash should be taken seriously and medically assessed promptly. (Medicines.org.uk)
Is Zyloric an antibiotic?
No. Allopurinol is a xanthine oxidase inhibitor and has no antimicrobial spectrum.
What is the active ingredient in Zyloric?
Allopurinol.
Does Zyloric contain 100 mg or 300 mg?
Both presentations are available: 100 mg and 300 mg tablets. Current Egyptian pharmacy listings identify 30-tablet packs for both strengths. (Vezeeta)
Who manufactures Zyloric in Egypt?
Current Egyptian pharmacy listings identify GlaxoSmithKline (GSK) as the manufacturer. The exact current Egyptian marketing-authorisation holder should be verified against the current Egyptian regulatory/product record rather than inferred solely from retail listings. (Vezeeta)
22. References
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Zyloric Tablets 100 mg, 300 mg – Summary of Product Characteristics (SmPC), electronic Medicines Compendium (emc). Current indexed SmPC; last updated on emc: 19 February 2025. (Medicines.org.uk)
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Zyloric Patient Information Leaflet, Health Products Regulatory Authority (HPRA), Ireland. Information covering indications, contraindications, interactions, pregnancy/breastfeeding, and administration. (HPRA Assets)
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GSK India – Zyloric Tablets product information, containing allopurinol 100 mg and 300 mg and detailed pharmacological/clinical information. (GSK India)
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Vezeeta Pharmacy Egypt – Zyloric 100 mg and Zyloric 300 mg listings, confirming current indexed Egyptian-market presentations, active ingredient, and manufacturer information. (Vezeeta)
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Tdawi Egypt – Zyloric 100 mg and 300 mg listings, confirming 30-tablet presentations and allopurinol strengths. (Tdawi)
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Re3aya Pharmacy Egypt – Zyloric 100 mg and 300 mg listings, including current indexed manufacturer/storage information. (Re3aya Pharmacy)
Verification note: The Egyptian retail sources confirm the currently indexed products, strengths, pack sizes, and manufacturer listings, but they are not a substitute for the Egyptian regulatory authority's current registered-product record. Therefore, regulatory/MAH statements that could not be independently verified have deliberately been qualified rather than presented as established facts.