Inadequate chronotherapeutic and chronotoxicological considerations in hypertensive therapy in Kaduna, Northern Nigeria

Temidayo Olurishe, John Maigida. Ahmadu Bello University, Zaria, Kaduna, Nigeria

Hypertensive patients get best blood pressure (BP) controls from their medication with good compliance levels. This can be hampered by several factors including missed doses, non compliance, poor compliance or time of administration. Chronotherapy involves the timing of drugs to attain adequate blood concentrations when the target disease is usually at its peak. BP has been observed to have a distinct circadian rhythm with nadir during night hours and peaks between awakening and midday. This study was designed as a preliminary evaluation of compliance with antihypertensive drug therapy and dosage timing among hypertensive patients in Kaduna, North of Nigeria. Three hundred patients participated in the study by filling out self administered questionnaires. Patients who were unable to fill out the questionnaire were assisted. Data from the questionnaires was subjected to descriptive and non parametric analysis. Sixty-seven percent of the patients were between the ages of 45 and 64. Seventy percent of the respondents claimed they complied with the timing of drug administration, while neither age nor sex was a significant factor in compliance with dosing time (Pearson-Chi square p>0.32). Source of drug didn’t affect the offering of counsel to patients on use of their medication. Duration as a hypertensive patient didn’t affect drug use pattern. Although drugs were obtained from diverse sources including patent drug stores, majority of patients (96%) reported to have been given directions on use of their drugs. Over 68% of respondents admitted to taking their missed dose anytime they remembered while 25% added the missed dose to their next dose. Over 40 and 36 percent of respondents admitted to using their drugs in the morning or at anytime of the day, although patients did not report being told the exact time of day to use their medication. Patients placed on two and three times daily doses used their drugs as morning-evening or morning-afternoon-evening doses which failed to reflect appropriate dosing intervals. Gender was a determinant of owning a personal BP apparatus and frequency of BP measurement (Pearson-Chi square p<0.001). While compliance with drug use appeared to be high, chrontherapeutic and chronotoxicological factors didn’t appear to be a consideration although these both play important factors in BP control and prevention of adverse cardiovascular events. Greater emphasis on dose timing is advocated with a view to carrying out an intervention programme.