Laboratory Monitoring of Hematological and Hepatic Parameters in Ambulatory Patients Receiving Alpha-Methyldopa in a Nigerian Tertiary Care Setting

The objective of the study is to assess the frequency and comprehensiveness of laboratory monitoring of hematological and hepatic parameters in ambulatory Nigerian hypertensive patients on methyldopa therapy. A retrospective cross sectional study was conducted between 1(st) February and 31(st) March 2007 at the Medical Outpatient Clinic of a 900-bed premier teaching hospital located in Ibadan, Nigeria. 260 case notes of hypertensive patients, out of the 1178 case notes of patients who had been prescribed at least 250 mg of methyldopa for at least 2 months, were reviewed. 22.1% of the hypertensive patients were on methyldopa alone or in combination with other anti-hypertensives for a mean period of 26.8+/-2.3 months (Range: 2-36 months). Overall, red cell count was prescribed and conducted in only 15.4% (40) of cohort. Only 4.2% (11) of patients had follow-up red cell count done after one month of methyldopa therapy; 9 out of these patients had marked reduction of red blood cells. Only 2.3% of cohort had baseline Liver Function Test (LFT) before start of methyldopa therapy and Alanine Transaminases and Aspartate transaminases levels were elevated in all patients. No patient had subsequent LFT prescribed and conducted particularly within 6-12 weeks of use of methyldopa. Direct Anti-Globulin Test was neither prescribed nor conducted in any of the cohort before and after commencement of methyldopa therapy. In conclusion, laboratory monitoring of ambulatory hypertensive patients on methyldopa therapy particularly for possible hematological and hepatic toxicities is less than optimal. The consequent therapeutic benefit of continuing considerable prescription and use of methyldopa in Nigeria is less likely to be realized without proper monitoring to preclude possible methyldopa-use related harms.