Voriconazole

Type of Medication: Antifungal

Indications: invasive aspergillosis; serious infections caused by Scedosporium spp; Fusarium spp. or invasive Candida spp resistant to fluconazole. ABPA in conjunction with steroids

Side Effects: Gastro- intestinal disturbances ( including nausea, vomiting,abdominal pain, diarrhoea); jaundice, oedema, hypotension, chest pain, RDS, sinusitus, headache, dizziness, asthesia, anxiety, depression, confusion, agitation, hallucinations, paraesthesia, tremor: influenza like symtoms, hypoglyceamia, haematuria, blood disorders( anaemia, thrombocytopenia, leucopenia, pancytopenia), acute renal failure, hypokaleamia; visual disturbances including altered perception, blurred vision and photophobia, rash, puritus, photosensitivity, alopecia, injection site reactions. Less commonly taste disturbances, cholecystitis, pancreatitis, hepatitis, constipation, arrythmias (including QT prolongation), syncope. For further reactions see summary of product characteristics.

Route of administration: Adult (Intravenous)

Dose:6 mg/kg every 12 hours for 2 doses the 4 mg/kg every 12 hours thereafter. Can be reduced to 3 mg/kg every 12 hours if not tolerated.Maximum duration of treatment 6 months.

Administration: Dilute 200 mg vial with 19 mls WFI. Dilute in either Glucose 5% or Sodium chloride 0.9% to produce a final concentration of 0.5 – 5 mg/ml. Maximum rate of infusion 3 mg/kg/hour

Route of administration: Adult (Oral)

Dose:Body weight> 40 kg: 400 mg every 12 hours for 2 doses then 200 mg every 12 hours thereafter. Can be increased to 300 mg every 12 hours if necessary. Body weight <40 kg: 200 mg every 12 hours for 2 doses then 100 mg every 12 hours thereafter. Can be increased to 150 mg every 12 hours if necessary.

Administration: An hour before food or on an empty stomach

Route of administration: Paediatric (Intravenous)

Dose:2-12 years: 7 mg/kg every 12 hours (reduced to 4 mg/kg every 12 hours if not tolerated). > 12 years: as per adults.

Administration: as per adults

Route of administration: Paediatric (Oral)

Dose:2-12 years: 200 mg every 12 hours (oral suspension recommended). over 12 years: as per adult regime

Administration: One hour before food or on an empty stomach

Examples of some Drug Interactions

Interacting drug: Amphoteracin

possibly antagoinse effect of amphoteracin

Interacting drug: Carbamazepine

reduces plasma concentration of voriconazole

Interacting drug: Ciclosporin

increases plasma concentration of ciclosporin

Interacting drug: Coumarins (inc warfarin)

Enhanced anticoagulant effect.

Interacting drug: Methadone

Increases plasma concentration of methadone, consider reducing dose.

Interacting drug: Omeprazole

increases plasma concentration of omeprazole – reduce dose

Interacting drug: Phenytoin

increased plasma concentration of phenytoin – monitor for signs of toxicity. Reduced plasma voriconale concentration – increase dose of voriconazole.

Interacting drug: Pimozide

increased risk of ventricular arrythmias

Interacting drug: Primadone

reduces plasma concentration of voriconazole – avoid concomitant use

Interacting drug: Quetiapine

increased plasma concentration of quetiapine – reduce dose

Interacting drug: Quinidine

increases plasma concentration of quinidine – increased risk of ventricular arrythmias avoid cincomitant use.

Interacting drug: Rifabutin

rifabuitin plasma concentration increased- monitor for signs of toxicity, voriconazole plasma conc decreased, increase dose of voriconazole.

Interacting drug: Rifampicin

plasma concentration of voriconazole reduced – avoid concomitant use.

Interacting drug: Sirolimus

increases plasma concentration of sirolimus – avoid concomitant use.

Interacting drug: Sulphonylureas

increased plasma concentration of sulphonylureas.

Interacting drug: Tacrolimus

increases plasma concentration of tacrolimus