What pre-existing condition could heighten the risk for adverse effects when treating with albendazole?

The correct choice is based on the interaction between albendazole and cimetidine. Cimetidine is known to inhibit certain enzymes in the liver that are involved in drug metabolism. When a client is taking cimetidine, it can slow the metabolism of albendazole, leading to increased levels of the drug in the bloodstream. This has the potential to heighten the risk of adverse effects due to the accumulation of the drug. Since the metabolism of albendazole is affected, the monitoring of the patient for side effects becomes crucial, especially if the cimetidine is taken regularly.

In contrast, while liver disease may increase the risk of drug toxicity due to decreased liver function, it would not have the same specific interaction with albendazole as cimetidine does. Lactose intolerance does not directly affect how albendazole is metabolized, making it irrelevant in the context of this question. Similarly, while taking antidepressants may have some potential interactions, they are not as significant as the known interaction with cimetidine.