Background -Hypertension is a leading cause of premature death globally and its prevalence is higher in low-and-middle income countries (LMICs) than in high countries. Studies on prescription patterns of antihypertensive found inconsistencies, thereby necessitating thorough investigations into the prescribing practices. Method - The study was a retrospective, descriptive, cross-sectional study of antihypertensive medicines prescriptions conducted at the Medical Outpatient Department of the Enugu State University Teaching Hospital, Nigeria. Data were analyzed using Statistical Packages for Social Sciences software version 23.0 for windows and Mann Whitney U test was used to determine the effect of identified drug related problems on the patients BP control. A p-value ˃ 0.05 was regarded as statistically significant with 95% confidence interval to test the level of significance Results - Bitherapy (45.36%) was the most common used form of therapy. Identified adverse drug reactions and unnecessary drug therapy were statistically significant at p-value = 0.036 and p-value = 0.025 respectively, in the patients with BP control. Calcium channel blockers (CCB) showed greatest systolic blood pressure (SBP) mean value reduction of 31.14 mmHg and diastolic blood pressure (DBP) median value of 1.00 mmHg, compared with other monotherapy prescribed, while the combination of CCB + Thiazides (THZ) + Angiotensin Converting Enzyme Inhibitors (ACEI) showed the highest SBP mean value reduction with 30.22 mmHg and DBP median value with 15 mmHg. Conclusion – There were deviations from the WHO prescribing practice guideline but majority of the prescribers complied with the JNC 8 treatment guidelines. Medication non-adherence, adverse drug reaction, dose too low and unnecessary drug therapy were the identified drug related problems. Calcium Channel Blockers, Thiazide diuretics and their combination-based were effective in reducing both the systolic blood pressure and diastolic blood pressure compared to other agents.