Allergic reactions are an example of hyper-sensitivity. Hyper-reactivity is another form of overreaction to a drug. These varied responses to a drug explain need for medical monitoring. G. Tolerance refers to a decrease in drug effect after repeated administrations of the same dosage. Different forms of tolerance.
Metabolic tolerance occurs when liver enzymes are induced by repeated use of a drug.
Cellular tolerance involves a change in the nerve cell as an adaptation to repeated use of a drug. Behavioral tolerance occurs when the individual learns to act normally despite the presence of a drug. Conditioned tolerance occurs with repeated use of a drug in a specific environment. Cross tolerance occurs when experience with one drug causes tolerance to another drug. Tolerance can develop at different rates for the various drug effects.