DRUG UTILIZATION PATTERN OF ANTIHYPERTENSIVE MEDICATIONS IN A TERTIARY CARE HOSPITAL, SOUTH INDIA

Objective: The objective of the study is to assess drug use pattern of antihypertensive medications in hypertensive patients. Methods: It is a prospective cross-sectional study conducted in the outpatient dispensary, Government Medical College, Thiruvananthapuram for the period of 6 months from January 2019 to June 2019. About 500 prescriptions of patients visiting outpatient dispensary with an antihypertensive prescription were enrolled for the study. Drug use patterns of different classes of antihypertensive medications were analyzed from individual prescriptions. Results: A total of 500 patients were included in this study, among which 281 were male (56.2%) and 219 (43.8%) were female. In 500 patients, 133 patients were treated with monotherapy. In that 42.1% of patients were treated with amlodipine, 28.57% of patients were treated with losartan. In combination therapy most commonly used was double therapy (42.8%) followed by triple therapy (24.2%). Calcium Channel Blockers (56.2%) was most prescribed class of drug followed by Angiotensin Receptor Blockers. Conclusion: This study reveals that calcium channel blockers as most prescribed class of antihypertensive and Amlodipine was the most prescribed antihypertensive. In our study, most of the patients were treated with combination therapy in that double drug therapy was most common. There is a chance of various medication errors, development of adverse drug reaction as majority (290) of patients belong to age above 60 and chances of getting error also increases as combination therapy is most used. Therefore close monitoring is required for such patients.


INTRODUCTION
Hypertension affects around one billion individuals worldwide and about 234 million adults are effected by the same in India by 2019 [1,2]. It is usually asymptomatic, chronic disorder needing lifelong treatment. Hypertension is defined as a sustained blood pressure greater than 90 mm Hg accompanied by an elevated systolic blood pressure 140 mm Hg [3]. Now a day's hypertension remains poorly controlled. It is due to multiple factors including low antihypertensive efficacy of singledrug therapy, reluctance of primary care physicians to modify or titrate initially chosen therapy to obtain target blood pressure, and poor compliance with medication [3,4]. Drug prescribing patterns vary from country to country and within various regions of individual countries [5]. It is, therefore, important to understand current antihypertensive medication patterns and their impact on blood pressure control. Drug utilization research can increase our understanding of how drugs are being used as follows. It can determine the pattern or profile of drug use and the extent to which alternative drugs are being used to treat particular conditions [6,7]. It can be used to compare the observed patterns of drug use for the treatment of a certain disease with current recommendations or guidelines [7]. The aim of this study was to detect the drug utilization pattern of antihypertensive prescribed.

Study design
Prospective cross sectional study. Informed consent was obtained from the patient and caregiver before commencing the study. Permission for checking case sheets of patients was obtained from the hospital authorities. All data will be kept confidential and was used for the purpose of this study only.

Statistical analysis
 Data obtained was entered into Microsoft Excel Sheet and analyzed using Statistical Package for the Social Sciences trial version 18.0. Qualitative variables will be expressed in percentages. Quantitative variables will be expressed in mean and standard deviation (SD) and its confidence interval.

RESULTS
In this prospective study, a total of 500 patients were enrolled and among these patients, 281 (56.2%) patient were males and 219 (43.8%) patients were females. Mean age in the study population from the Table 1 was found to be 59.69 (±9.738) years. Results from the table showed that among 500 patients 58% were in the age group of ≥60 years and 42% were of age group of <60 years.
This study also showed that 30% of patients have a family history of Hypertension and 70% does not have any family history of hypertension.
In case of social habits, 14 patients were smokers, 10 patients were alcoholic, 63 were ex-alcoholic, and 104 were ex-smokers ( Table 1).
The enrolled patients were categorized, based on blood pressure level as per the Joint National Committee guideline (JNC-8). Among 500 patients, most of the patients belong to stage 1 hypertension (31.8% having systolic blood pressure and 36.4% having diastolic blood pressure). In stage 2 hypertension 23.4% have systolic blood pressure and 14.6% have diastolic blood pressure ( Table 2).

DISCUSSION
This study was conducted in the outpatient dispensary, Government Medical College Hospital, Thiruvananthapuram, Kerala, and a total of 500 patients were enrolled. The study duration was a period of 6 months. In the study, among the 500 patients, 281 (56.2%) patients were males and 219 (43.8%) patients were females, which was similar to another study conducted by Amit Sharma et al. in his study 55.3% were male and 44.7% were female [8]. Majority of patients (58%) in the study were in the age group of greater than or equal to 60 and 42% were in the age group less than 60. The mean±SD age in the study population was 59.69±9.738 years. Dhanaraj et al. also reported that mean SD age as 56.5±10.1 in the study conducted in Chandigarh [9].
In our study, 30% (150) of patients have a family history of hypertension. This observation was in accordance with another study conducted at outpatient department of tertiary care hospital in Andhra Pradesh in which 23.7% had family history of hypertension [10]. The enrolled patients were categorized based on blood pressure level in adults as per JNC-8 [11]. Among 500 patients, most of the patients belong to stage 1 hypertension this was similar to the study of Cidda [12]. Hypertension is usually associated with

Anuradha et al.
The analysis of the present study indicates that 73.4% of patients were treated with combination therapy and only 26.6% of patients were treated with monotherapy. A similar report was established in another different studies [14][15][16]. In patients those who received monotherapy, 42.1% patients were treated with Amlodipine, 28.57% patients were treated with Losartan, and 9.77 % were receiving Telmisartan and Metoprolol followed by Cilnidipine (3%), Olmesartan, Ramipril, and Enalapril (1.5%). Monotherapy is able to normalize blood pressure in less than a quarter of patients with Hypertension. This was similar to the result of Varakantham et al. and Jarari et al. studies were Amlodipine was the most common drug used [17,18].
In combination therapy most commonly used was double therapy (42.8%) followed by triple therapy (24.2%), four drugs (5.6%), and five drug therapy (0.6%). In the study conducted by Rakesh et al. also double drug therapy was the most preferred combination therapy [19].
The study revealed that Calcium Channel Blocker (281) either alone or in combination was the most commonly prescribed class of drug, in that majority patients were prescribed with Amlodipine as first-line Calcium Channel Blocker (84.34%) followed by Clinidipine (     co-morbidities such as heart diseases, diabetes, stroke, and kidney failure [11]. The analysis of this study population shows that 53% had CAD, 46.6% had diabetes, 42% had dyslipidemia, 13.4% had hypothyroidism, 5.8% had CKD, and 5.2% had Stroke. Akintunde et al. also found similar result in their study [13].

CONCLUSION
In most cases, hypertension will lead to several other diseases including cardiovascular and renal diseases. In our study population most frequently observed comorbidity was CAD and Diabetes Mellitus. Majority were having stage 1 hypertension and 30% had family history of hypertension. Most of the patients were treated with combination therapy in that double drug therapy was most common. Combination therapy was preferred as majority of patients were having comorbidities. On analysis of drug use pattern calcium channel blocker was most prescribed class of antihypertensive and drug was Amlodipine.
Most geriatric patients were on combination therapy so avoiding polypharmacy and promoting rational use of drug should be considered while prescribing. Fixed-dose combinations can be preferred for geriatric patients with proper monitoring.
Limitations of the study include single centered and limited time period for follow-up. If the study was conducted in larger sample size for long duration more significant results would have been obtained.