Drug Interactions between albendazole and Ircon-FA

MONITOR: Ethanol may increase folic acid elimination and folic acid absorption is decreased in chronic alcoholics. Excessive alcohol consumption may lead to folate deficiency.

MANAGEMENT: Monitoring of patient response to folic acid supplementation if they also consume alcohol regularly may be recommended.

ADJUST DOSING INTERVAL: Food enhances the oral bioavailability of albendazole, which is rapidly converted by hepatocytes and intestinal mucosal cells into the active metabolite, albendazole sulfoxide (ABZSX), following absorption. The proposed mechanism is stimulation of gastric acid secretion, as the absorption of albendazole is thought to be pH-dependent. According to the product labeling, plasma concentrations of ABZSX are up to 5-fold higher on average when albendazole is administered with a fatty meal (fat content approximately 40 g) compared to administration in the fasted state. In one study of six healthy male volunteers, administration of a single 10 mg/kg oral dose of albendazole in combination with a high-fat meal (57 g fat, 1399 kcal) increased the mean ABZSX peak plasma concentration (Cmax) and systemic exposure (AUC) by 6.5- and 9.4-fold, respectively, and delayed the time to reach Cmax (Tmax) from 2.5 to 5.3 hours compared to administration in the fasted state with water. The elimination half-life was not affected.

MONITOR: Grapefruit juice may increase the oral bioavailability of albendazole, which is rapidly converted by hepatocytes and intestinal mucosal cells into the active metabolite, albendazole sulfoxide (ABZSX), following absorption. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit. In six healthy male volunteers, administration of a single 10 mg/kg oral dose of albendazole in combination with 250 mL of double-strength grapefruit juice increased the mean ABZSX peak plasma concentration (Cmax) and systemic exposure (AUC) by 3.2- and 3.1-fold, respectively, compared to administration with water. However, because pharmacokinetic interactions involving grapefruit juice are often subject to a high degree of interpatient variability, the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: To ensure maximal oral absorption, albendazole should be taken with food. Grapefruit juice may also enhance the oral bioavailability of albendazole.

ADJUST DOSING INTERVAL: Concomitant use of some oral medications may reduce the bioavailability of orally administered iron, and vice versa.

Food taken in conjunction with oral iron supplements may reduce the bioavailability of the iron. However, in many patients intolerable gastrointestinal side effects occur necessitating administration with food.

MANAGEMENT: Ideally, iron products should be taken on an empty stomach (i.e., at least 1 hour before or 2 hours after meals), but if this is not possible, administer with meals and monitor the patient more closely for a subtherapeutic effect. Some studies suggest administration of iron with ascorbic acid may enhance bioavailability. In addition, administration of oral iron products and some oral medications should be separated whenever the bioavailability of either agent may be decreased. Consult the product labeling for specific separation times and monitor clinical responses as appropriate.