On-target toxicity is also referred to as mechanism-based toxicity. This type of adverse effect that results from pharmaceutical drug exposure is commonly due to interactions of the drug with its intended target. In this case, both the therapeutic and toxic targets are the same. To avoid toxicity during treatment, many times the drug needs to be changed to target a different aspect of the illness or symptoms. Statins are an example of a drug class that can have toxic effects at the therapeutic target (HMG CoA reductase).