Clinical pharmacology: special safety considerations in drug development and pharmacovigilance

The dose of a drug is a major determinant of its safety, and establishing a safe dose of a novel drug is a prime objective during clinical development. The design of pre-marketing clinical trials precludes the representation of important subpopulations such as children, the elderly and people with co-morbidities. Therefore, postmarketing surveillance (PMS) activities are required to monitor the safety profile of drugs in real clinical practice. Furthermore, individual variations in pharmacogenetic profiles, the immune system, drug metabolic pathways and drug-drug interactions are also important factors in the occurrence of adverse drug reactions. Thus, the safety of a drug is a major clinical consideration before and after it is marketed. A multidisciplinary approach is required to enhance the safety profile of drugs at all stages of development, including PMS activities. Clinical pharmacology encompasses a range of disciplines and forms the backbone of drug safety consideration during clinical drug development. In this review we give an overview of the clinical drug development process and consider its limitations. We present a discussion of several aspects of clinical pharmacology and their application to enhancing drug safety. Pharmacokinetic-pharmacodynamic modelling provides a method of predicting a clinically safe dose; consideration of drug pharmacokinetics in special populations may enhance safe therapeutics in a wider spectrum of patients, while pharmacogenetics provides the possibility of genotype-specific therapeutics. Pharmacovigilance activities are also discussed. Given the complex nature and unpredictability of type B reactions, PMS activities are crucial in managing the risks drugs pose to the general population. The various aspects of clinical pharmacology discussed make a strong case for this field as the backbone of optimising and promoting safe development and use of drugs.