Assessing the safety profile of a new antihypertensive agent

GUIDELINES ON DRUG SAFETY: Recent European Union draft guidelines for the safety evaluation of drugs intended for long-term use state that during drug development the safety profile of the new compound should be assessed over a period of time consistent with intended usage. This is in reasonable agreement with guidelines prepared by other regulatory authorities. CLINICAL DRUG DEVELOPMENT: Satisfactory preclinical data on a new compound are used to obtain authorization for human testing from the National Committees on Safety of Medicines. Clinical trials are performed in four phases, ranging from phase I studies performed on healthy volunteers (n = 20-50) to postmarketing (phase IV) studies. The latter are of great importance as they cover large patient populations (n = 2000 to > or = 10,000) and allow detection of rare adverse drug reactions. ADVERSE DRUG REACTIONS: Type B reactions are serious, unpredictable reactions to a drug that necessitate treatment withdrawal. Type A reactions are dose-dependent, and represent the majority of adverse reactions. They are often managed by dose reduction rather than drug withdrawal. ADVERSE REACTIONS TO ANTIHYPERTENSIVE AGENTS: Examples of type B adverse reactions to antihypertensives are the cutaneous and ocular reactions to practolol, and angioneurotic oedema associated with angiotensin converting enzyme inhibitors. Lacidipine, a second-generation calcium antagonist, is an example of a modern antihypertensive agent with a favourable safety profile. The adverse reactions associated with lacidipine are mild to moderate and of the A type, the major ones being those typical of calcium antagonists (headache, flushing and pedal oedema due to vasodilation.