Background: The Majority of hypertensive patients have their blood pressure
uncontrolled. If it is left being uncontrolled, hypertension could risk worsing
health conditions and possibly causing complications. The rational choice of
drugs plays an important role in achieving therapeutic success. The existence of
ESO has the potential to reduce the compliance of hypertensive patients during
therapy making the goals of therapy unachieved. Method: This type of
observational analytic study was designed with a prospective cohort approach
conducted on 28 respondents by recording the use of antihypertensive drugs and
blood pressure of hypertensive outpatients before and after taking
antihypertensive drugs. Follow ups were carried out in February, March and April
to see the rationality, effectiveness and relationship between the two. Data were
analyzed using Paired Sample t test and Chi-Square. ESO monitoring uses the
Naranjo Algorithm. Results: Rationality analysis showed 100% right indication,
100% right patient, 83.33% right drug, 100% right dose, 100% right route of
administration. The paired sample t test shows a systolic significance value of
0.045; diastolic of 0.006 and MAP of 0.011. The chi-square test showed a systolic
significance value of 0.023; diastolic of 0.141 and MAP of 0.086. Of the 28
respondents, 5 patients experienced antihypertensive ESO with 7 events namely
dizziness, dry cough, skin rash, hyperuricemia, hyperkalemia. Conclusion: Blood
pressure has decreased significantly, as many as 14 prescriptions are considered
irrational, there is a relationship between rationality and a decrease in systolic,
there is no relationship between rationality and a decrease in diastolic and MAP.