Itrazol 100 mg OD for 7 days
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Itrazol itraconazole 100mg once daily 7 days indication
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Here is a complete clinical overview of Itrazol (Itraconazole) 100 mg once daily for 7 days:
Itrazol (Itraconazole) 100 mg OD x 7 Days
Drug Identity
Itrazol is a brand name for itraconazole, a broad-spectrum triazole antifungal. It inhibits fungal 14-alpha-demethylase (CYP51), blocking lanosterol → ergosterol conversion, disrupting fungal cell membrane integrity.
Is 100 mg OD x 7 Days an Established Regimen?
Yes - but the typical regimens vary by indication. 100 mg once daily is a lower-dose schedule. Common itraconazole regimens include:
| Indication | Dose / Duration |
|---|---|
| Tinea corporis / cruris / capitis / pedis | 100 mg BD x 5-7 days OR 200 mg OD x 7 days |
| Pityriasis versicolor (PV) | 200 mg OD x 7 days (or 100 mg BD x 5 days) |
| Vulvovaginal candidiasis | 200 mg OD x 3 days |
| Oral / cutaneous candidiasis | 100 mg OD x 14 days |
| Tinea manuum | 100 mg BD x 5 days |
| Onychomycosis | 200 mg OD continuous x 6 weeks (fingernails) / 12 weeks (toenails); OR pulse 400 mg/d x 1 week/month |
| Deep mycoses | Loading: 200 mg TDS x 3 days, then 200 mg OD or BD |
100 mg OD x 7 days most likely targets a superficial dermatophyte or cutaneous candidal infection (e.g., tinea, oral candidiasis in non-immunocompromised patients), though it is a sub-standard dose for pityriasis versicolor or tinea pedis where 200 mg/day is preferred.
Pharmacokinetics
- Absorption: Highly lipophilic; capsule form requires gastric acidity - take after a full meal for best absorption. The oral solution is taken on an empty stomach.
- Protein binding: >99% (plasma proteins)
- Half-life: ~21 hours
- Metabolism: Extensive hepatic CYP3A4 metabolism; active metabolite is hydroxy-itraconazole (roughly equal concentration to parent drug, also biologically active)
- Distribution: Highly lipophilic; accumulates in skin, nails, fatty tissue. Nail drug reservoir persists 6-9 months after stopping.
- Renal excretion: Minimal - no dose adjustment for renal impairment (except IV form: avoid if CrCl <30 mL/min)
Important Adverse Effects
| Category | Effects |
|---|---|
| GI (most common) | Nausea, abdominal pain, unpleasant taste (cyclodextrin solution) |
| Cardiac | Negative inotrope - can precipitate or worsen CHF/heart failure |
| Metabolic (elderly) | Triad of edema + hypertension + hyperkalemia |
| Hepatic | Hepatitis, jaundice (uncommon but monitor LFTs) |
| Skin | Stevens-Johnson syndrome (rare) |
| Neurological | Peripheral neuropathy (rare) |
| Endocrine | Adrenal suppression (rare) |
- (Fitzpatrick's Dermatology, p. 3475)
Key Contraindications
- Heart failure or history of cardiac disease
- Pregnancy / women planning pregnancy (teratogenic - Category C/D)
- Hepatic impairment - requires dose adjustment in progressive liver disease
- Co-administration with CYP3A4-sensitive drugs (see interactions below)
Major Drug Interactions (CYP3A4 inhibition)
Itraconazole is both a CYP3A4 substrate AND inhibitor, and also inhibits P-glycoprotein. This causes dangerous elevation of co-administered drugs:
Absolutely contraindicated combinations:
- Terfenadine, astemizole, mizolastine (antihistamines - QT prolongation / torsades)
- Cisapride, pimozide, sertindole
- Statins: simvastatin, lovastatin, atorvastatin (rhabdomyolysis risk)
- Oral midazolam, triazolam (profound sedation)
- Ergot alkaloids (dihydroergotamine, ergotamine)
- Quinidine, dofetilide (arrhythmia)
- Nisoldipine, bepridil
Levels reduced by (CYP3A4 inducers - avoid or monitor):
- Rifampicin, rifabutin, phenytoin, carbamazepine, isoniazid
Administration Tips
- Take with or after a full meal (capsule form) to maximize absorption
- Avoid antacids, H2 blockers, PPIs before the dose (reduce gastric acidity = impaired absorption)
- Check for drug interactions before prescribing
Special Populations
- Children: Lower plasma concentrations - twice-daily dosing often needed; dose 5 mg/kg/day
- Elderly: Watch for edema-hypertension-hyperkalemia triad
- Hepatic impairment: Use with caution; hepatic dose adjustment required
- Renal impairment: Generally safe (capsule/oral); avoid IV if CrCl <30
Sources: Fitzpatrick's Dermatology (p. 3474-3476), Goodman & Gilman's Pharmacological Basis of Therapeutics, Harrison's Principles of Internal Medicine 22e, Medsafe datasheet (Itrazole)
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