The present study indicates that GPs working at primary healthcare centres were rational in terms of antihypertensive drug choice. However, they poorly applied rational pharmacotherapy principles such as (a) writing a "good" prescription which is easily readable by the pharmacist and the patient and that contains full essential information; (b) a medical examination of the patient to assess her/his current clinical condition; and (c) taking care of not prescribing drugs with potential interaction like antihypertensives and NSAIDs together.