Composition
The active ingredient of Zestaval® is Albendazole.
Properties
Albendazole is benzimidazole anthelmintic structurally related to Mebendazole (Thelmox) and is similarly active against most nematode and some cestode worms. It appears to act by irreversibly inhibiting glucose uptake by susceptible worms, resulting in depletion of the worms energy sources, glycogen and adenosinetriphosphate (ATP), and their slow death.
Albendazole is poorly absorbed from the gastro-intestinal tract, but rapidly undergoes extensive first-pass metabolism. Its principal metabolite is mainly excreted in the urine.
Indications
Zestaval® is indicated in the treatment of hydatid cysts caused by Echinococcus granulosus or E. multiocularis. Zestaval® may be used as first-line medical therapy in patients with hydatid disease or as an adjunct to surgery, either pre- or post- operatively.
Dosage
Zestaval® 200mg: To be swallowed whole with a glass of water.
Zestaval® 400mg: To be chewed slowly in the mouth.
Adults and elderly: Echinococcus granulosus: Zestaval® is normally given at a dose of 800mg/day in divided doses for 28 days, followed by 14 drug-free days.
Up to three cycles of Zestaval® treatment may be given. If signs of treatment-effect (cyst disappearance or shrinkage, alteration in X-ray appearance or ultrasound/CT scan density or membrane separation) are not seen within three cycles, further treatment is unlikely to produce a response. Zestaval® shows greatest efficacy in the treatment of liver, lung and peritoneal cysts.
Pre-surgery: Dosage is 800mg/day in divided doses for 28 days followed by a period of 14 drug-free days. The 28-day course is repeated once prior to surgery. Where surgical intervention is necessary before completion of two cycles of treatment, Zestaval® should be given for as long as possible before surgery, but for not more than 28 days at a time.
Pre- and post- surgery: Where only a short pre- operative course of Zestaval® has been given, and in cases where emergency surgery is required, Zestaval® should be given post-surgically for 28-day cycles separated by 14 days. In addition, where cysts are found to be viable after pre-surgical treatment, a full two-cycle course should be given. Echinococcus multilocularis: 800mg/day in divided oral doses for 28 days followed by 14 drug-free days. Long treatment with regular monitoring may be required.
Side Effects
Gastrointestinal disturbances, headaches and dizzines have been reported during treatment. These symptoms are usually mild and resolve without treatment. Alopecia, usually limited to thinning of hair has been reported in about 2% of cases and is reversible on cessation of treatment. Rash and fever have been reported, especially during the first few days of treatment. Allergic shock has been observed where cyst leakage has occurred during treatment. In patients where there is cerebral involvement, convulsions and meningism may occur during treatment.