Tab Alop TC
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Alop TC tablet allopurinol uses dosage
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Tab Alop TC
Alop TC is a combination tablet containing Allopurinol + Tranexamic Acid — though in many formulations and markets, "Tab Alop TC" typically refers to a brand of Allopurinol tablet (TC = tablet coated). Below is a comprehensive overview of Allopurinol, the primary active ingredient.
Allopurinol — Overview
Class: Xanthine oxidase inhibitor (XOI)
Primary Use: Urate-lowering therapy in gout and hyperuricemia
Mechanism of Action
Allopurinol (and its active metabolite oxypurinol) inhibits xanthine oxidase, the enzyme responsible for converting hypoxanthine → xanthine → uric acid. This reduces both serum and urinary uric acid levels.
Indications
| Indication | Notes |
|---|---|
| Chronic gout | First-line urate-lowering agent |
| Hyperuricemia | Secondary to diuretics, CKD, or myeloproliferative disorders |
| Uric acid nephrolithiasis | Reduces urinary urate load |
| Tumor lysis syndrome prevention | Used prior to chemotherapy |
| Lesch-Nyhan syndrome | Reduces uric acid overproduction |
Dosing
- Starting dose: 100 mg/day (or even 50 mg/day in CKD)
- Titration: Increase by 100 mg every 2–4 weeks
- Target: Serum urate < 5–6 mg/dL
- Maximum dose: 800 mg/day
- Administration: Single morning dose; taken after meals to reduce GI upset
In chronic kidney disease (CKD), start lower based on eGFR:
- eGFR 30–45 mL/min → start at 50 mg/day, titrate slowly (Harrison's, p. 10435)
Adverse Effects
| Adverse Effect | Details |
|---|---|
| Mild rash | ~2% of users; drug should be stopped |
| Severe cutaneous adverse reactions (SCARs) | Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) — rare but life-threatening |
| GI upset | Nausea, diarrhea |
| Allopurinol hypersensitivity syndrome | Fever, rash, hepatitis, renal failure |
| Gout flare (on initiation) | Due to rapid urate crystal mobilization |
Risk reduction: Starting low and titrating up minimizes the risk of SCARs and initiation flares.
Key Drug Interactions
| Drug | Interaction |
|---|---|
| Azathioprine / 6-mercaptopurine | Allopurinol inhibits their metabolism → severe toxicity (dose reduction of ~75% required) |
| Warfarin | May potentiate anticoagulant effect |
| Ampicillin/Amoxicillin | Increased risk of rash |
| Theophylline | Increased theophylline levels |
| Cyclophosphamide | Enhanced myelosuppression |
Contraindications
- History of hypersensitivity to allopurinol
- Acute gout flare (do not initiate during an acute attack; wait for flare resolution)
- Caution: HLA-B*5801 allele carriers (common in Han Chinese, Korean, Thai populations) — markedly elevated SJS/TEN risk; genetic screening recommended before starting therapy in these populations
Monitoring
- Serum uric acid (target < 6 mg/dL, ideally < 5 mg/dL in tophaceous gout)
- Renal function (dose adjustment in CKD)
- LFTs (baseline and periodically)
- Watch for rash — any rash warrants stopping the drug
Source: Harrison's Principles of Internal Medicine, 21st Edition, p. 10435
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