Clinical pharmacology in general practice: Bioavailability and therapeutic outcome

ABSTRACT

When physicians administer drugs to their patients.They do so in the expectation that the anticipated therapeutic effect will result.They are dismayed, therefore, when the patient either derives inadequate or no therapeutic benefit from the medication or worse still develops toxicity.Pharmacological principles state that effective drug therapy requires, not only that the appropriate drugs be given in adequate doses for adequate periods, but also that adequate concentraction of the drug must reach the site of action (blood) to be able to produce a reaponse.Bioavailability is the fraction of the admistered does which reaches the systemic circulation to be available to the receptors to produce a response and this is now reconized as one of the most important factors which determine the therapeutic outcome of many drugs.From the research done, the paper described two different done, the paper described two different aspects of bioavaility, which have to be taken into consideration.The first, fractional bioavailability, is due to the difference in the formulation of the same drug like Lariam and Mephaquin, as with mefloquine.The second phrmacokinetic availability, is due to difference in pharmacokinetics between sex, ethnic groups or diseases states like diarrhea and malaria. In addition, blood levels of different drugs like dapsone, chloroquine and propranolol can still differ (increased, descreases or delayed), .even in the same disease condition making off-hand prediction of response differcult.The use of clinical pharmacology to overcome this difficulty is discussed.