Non-responsiveness to antimicrobial therapy.

During the course of treating patients the clinician is faced with the problem of non-response to drugs. The expected therapeutic benefit is not observed. The cause may lie in the diagnosis, sub-type of disease, in the resistance of invading micro-organism or the drug itself. The drug dose, frequency, duration, mode of administration, compliance may be inadequate, inappropriate; the patient's pharmacokinetic profile may be unexpected, unusual; there may be alteration in the receptor, population, type, compensatory mechanism of the body etc. The relative importance of the host, parasite and drug related factors varies with disease, type of patient and drug under consideration. In the second section of the Clinical Pharmacology series, the causes of non-responsiveness to drugs will be discussed with reference to a few common diseases. The principles are applicable to may others.