Postmarketing pharmacokinetic and pharmacodynamic equivalence of generic and brand atenolol in Egypt.

Concerns have been raised regarding the postmarketing quality of generic drugs. This study assessed the pharmacokinetic and pharmacodynamic equivalence of generic and brand atenolol tablets in 24 healthy male volunteers in a single-dose, open, randomized, two-period crossover study under fasting conditions. Blood samples were collected for 24 h post dosing and assayed for atenolol using HPLC. Blood pressure and heart rate were measured at baseline and throughout blood sampling. The mean plasma concentration-time curves for both products were similar. Pharmacokinetic and statistical analysis indicated bioequivalence based on the mean ratios of log-transformed Cmax and AUC values. Both products had similar time courses of pharmacodynamic activity with a significant fall in blood pressure and heart rate (maximum after ~5 h) followed by a gradual increase towards baseline. Both products were well tolerated. Both atenolol products were bioequivalent in the postmarketing setting and can be used interchangeably in clinical practice.