Voriconazole, a triazole antifungal agent

Voriconazole, a triazole antifungal agent, is available as a lyophilized powder for solution for intravenous infusion, film-coated tablets for oral administration, and as a powder for oral suspension. Voriconazole is designated chemically as (2R, 3S)-2-(2, 4-difluorophenyl)-3-(5-fluoro-4pyrimidinyl)-1-(1H-1, 2, 4-triazol-1-yl)-2-butanol with an empirical formula of C16H14F3N5O and a molecular weight of 349.3.





Antimicrobial Spectrum:

Opportunisitic yeasts: Candida albicans, Candida tropcialis, Candida glabrata, Candida krusei, Cryptococcus neoformans,
Opportunistic hyaline moulds: Aspergillus spp., Fusarium spp. (variable activity), Scedosporium spp. (variable activity)
Dimorphic moulds: Histoplasma capsulatum, Coccidioides immitis, Blastomyces dermatitidis,
Parracoccidioides brasiliensis, Sporothrix schenkii, Penicillium marneffei
Dematiaceous moulds: variable activity



Indications:

Treatment of invasive aspergillosis; treatment of esophageal candidiasis; treatment of candidemia (in non-neutropenic patients); treatment of disseminated Candida infections of the skin and viscera; treatment of serious fungal infections caused by Scedosporium apiospermum and Fusarium spp (including Fusarium solani) in patients intolerant of, or refractory to, other therapy

Mechanism of Action:
Inhibits fungal cytochrome P450 3A dependent enzyme, decreases ergosterol synthesis (prinicipal sterol in fungal cell wall membrane) and inhibits cell membrane formation.

Adverse Reaction:

Ocular: visual changes (photophobia, color changes, increased or decreased visual acuity, or blurred vision)
Cardiovascular System: tachycardia, hypertension, hypotension, vasodilation, peripheral edema
Central Nervous System: fever, chills, headache, hallucinations, dizziness
Endocrine: hypokalemia, hypomagnesemia
Gastrointestinal: nausea, vomiting, abdominal pain, diarrhea, xerostomia
Hematologic: thrombocytopenia
Hepatic: alkaline phosphatase increased, serum transaminases increased
Renal: acute renal failure

Dosage:

Injection, powder for reconstitution: 200 mg
Tablet: 50 mg, 200 mg
Adults and pediatric patients above 2 years
IV: 6 mg/kg BID on day 1, followed by 4 mg/kg BID
PO: 400 mg BID on day 1 (below 40 kg: 200 mg BID), followed by 200 mg BID (below 40 kg: 100 mg BID)

Contraindications/Warnings/Precautions:

Coadministration of CYP3A4 substrates which may lead to QT prolongation (cisapride, pimozide, quinidine); co-administration with long acting barbiturates, carbamazepine, ergot alkaloids, rifampin, rifabutin, and sirolimus
Visual changes are commonly associated with treatment. Serious hepatic reactions have occurred during treatment, primarily in patients with serious concominant medical conditions.

Drug Interactions:

Voriconazole is a potent inhibitor of the cytochrome P450 3A4 isoenzyme system. Caution should be exercised and monitoring is suggested when concomitantly administering voriconazole with drugs that have narrow therapeutic windows and are substrates of the CYP3A4 substrates.

Pregnancy Risk Factor: D

Monitoring parameters: Hepatic, renal, visual function.

Brand names/Manufacturer:

VFEND (Pfizer - UNITED KINGDOM, USA, PORTUGAL, IRELAND, FRANCE, SPAIN, AUSTRALIA,
HUNGARY, SWEDEN, DENMARK, ISRAEL, FINLAND, BELGIUM, NORWAY, ITALY, GERMANY, HONG KONG)



Reference
https://www.webmd.com/drugs/2/drug-63366-5326/voriconazole-oral/voriconazole-oral/details
https://reference.medscape.com/drug/vfend-voriconazole-342598
https://medlineplus.gov/druginfo/meds/a605022.html
https://www.drugbank.ca/drugs/DB00582
https://www.rxlist.com/vfend-drug.htm
https://www.medicines.org.uk/emc/product/7383/smpc
http://www.antimicrobe.org/drugpopup/voriconazole.htm
https://academic.oup.com/cid/article/36/5/630/454409
Voriconazole, a triazole antifungal agent Voriconazole, a triazole antifungal agent Reviewed by gafacom on June 26, 2020 Rating: 5

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