Wolbachia are necessary to the parasitic worms moulting and population reduction by albendazole prevents this and kills the adults. Pharmacokinetics
Oral absorption of albendazole varies among species, with 1–5% of the drug being successfully absorbed in humans, 20–30% in rats, and 50% in cattle.The absorption also largely depends on gastric pH. People have varying gastric pHs on empty stomachs, and thus absorption from one person to another can vary wildly when taken without food. Generally, the absorption in the GI tract is poor due to albendazoles low solubility in water. It is, however, better absorbed than other benzimidazole carbamates. Food stimulates gastric acid secretion, lowering the pH and making albendazole more soluble and thus more easily absorbed. Oral absorption is especially increased with a fatty meal, as albendazole dissolves better in lipids, allowing it to cross the lipid barrier created by the mucus surface of the GI tract. To target intestinal parasites, albendazole is taken on an empty stomach to stay within the gut.Absorption is also affected by how much of the albendazole is degraded within the small intestine by metabolic enzymes in the villi. The pharmacokinetics of albendazole differ slightly between men and women: women have a lower oral clearance and volume of distribution, while men have a lower serum peak concentration.Albendazole undergoes very fast 1st-pass metabolism in all species, such that the unchanged drug is undetectable in plasma.
Those being treated for retinal neurocysticercosis can face retinal damage if they are not first checked for ocular cysticeri, since changes to existing lesions in the eye by albendazole can cause permanent blindness. Overdose
Because of its low solubility, albendazole often cannot be absorbed in high enough quantities to be toxic. The oral LD50 of albendazole in rats was found to be 2,500 mg/kg. It takes 20 times the normal dose to kill a sheep, and 30 times the normal dose to kill cattle. Overdose affects the liver, testicles, and GI tract the most. It can manifest with lethargy, loss of appetite, vomiting, diarrhea, intestinal cramps, dizziness, convulsions, and sleepiness. There is no specified antidote. Interactions
The antiepileptics carbamazepine, phenytoin, and phenobarbital lower the plasma concentration and the half life of albendazole sulfoxides R(+) enantiomer. The antacid cimetidine heightens serum albendazole concentrations, increases the half life of albendazole, and doubles albendazole sulfoxide levels in bile. It was originally thought to work by increasing albendazole bioavailability directly; however, it is now known that cimetidine inhibits the breakdown of albendazole sulfoxide by interfering with CYP3A4. The half-life of albendazole sulfoxide thus increases from 7.4 hours to 19 hours. This might be a helpful interaction on more severe cases, because it boosts the potency of albendazole. Paradoxically, cimetidine also inhibits the absorption of albendazole by reducing gastric acidity.Several other interactions exist. Corticosteroids increase the steady-state plasma concentration of albendazole sulfoxide; dexamethasone, for example, can increase the concentration by 56% by inhibiting the elimination of albendazole sulfoxide.