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Year : 2013  |  Volume : 4  |  Issue : 4  |  Page : 154-159

Evaluation of the drug utilization pattern at a regional psychiatric hospital, in Benin city, Nigeria

1 Department of Pharmacy, Federal Neuropsychiatric Hospital, Benin, Edo, Nigeria
2 Department of Clinical Services, Federal Neuropsychiatric Hospital, Benin, Edo, Nigeria

Date of Web Publication18-Dec-2013

Correspondence Address:
Hillary O Odo
Department of Pharmacy, Federal Neuropsychiatric Hospital, P.M.B 1108, Benin, Edo
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2045-080X.123222

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Background: Drug utilization research facilitates the rational use of drugs and suggests measures to improve prescribing habits. Irrational use of drugs is a global problem affecting patient care. It results in increased mortality, morbidity, adverse drug events, and wastage of economic resources.
Objectives: To evaluate the pattern of drug utilization at a regional neuropsychiatric hospital, in Benin City, Nigeria using some of the World Health Organization (WHO) prescribing indicators.
Materials and Methods: Data was obtained retrospectively from a review of 5400 outpatient prescriptions between September 2007 and August 2012. Data were analyzed using the WHO guideline for assessment of drug use in health facilities. The number of DDD per one thousand inhabitants per day was calculated from data on the number and size of dispensed drugs obtained from the out-patient pharmacy. Drug Utilization 90% (DU 90%) method was used to evaluate the quality of drug prescribing.
Results: An average of 2.88 drugs was prescribed per encounter, 94.38% of the drugs were prescribed using their generic names, and the percentage of encounters with antibiotics prescribed was 3.2% while 99.2% of all the drugs prescribed were prescribed from the essential drugs list. The drugs whose utilization accounted for about 90% of the entire drug use (DU 90%) were; haloperidol (15.5%), amitriptyline (22.3%), benzhexol (12.6%), trifluoperazine (20.3%), chlorpromazine (15.2%), and carbamazepine (7.9%). Haloperidol was the most utilized drug in this setting with a DDD per 1000 inhabitants per day of 5. In about 70% of the prescriptions encountered, all the drugs prescribed were available from the hospital pharmacy.
Conclusion: This study found that polypharmacy was commonly practiced while haloperidol was the most utilized psychotropic agent at the study facility.

Keywords: Drug use indicators, polypharmacy, prescription pattern, psychiatry, rational drug use

How to cite this article:
Odo HO, Olotu SO, Agbonile IO, Esan PO, James BO. Evaluation of the drug utilization pattern at a regional psychiatric hospital, in Benin city, Nigeria. Arch Pharma Pract 2013;4:154-9

How to cite this URL:
Odo HO, Olotu SO, Agbonile IO, Esan PO, James BO. Evaluation of the drug utilization pattern at a regional psychiatric hospital, in Benin city, Nigeria. Arch Pharma Pract [serial online] 2013 [cited 2019 Jul 16];4:154-9. Available from: http://www.archivepp.com/text.asp?2013/4/4/154/123222

  Introduction Top

Drug utilization research involves the prescription and use of drugs with emphasis on the resulting medical, social, and economic consequences. [1] Medicines are essential in health care delivery, therefore, the availability and affordability of good quality and efficacious drugs in addition to their rational use is a sine qua none to an effective health care delivery system. [2] However, irrational and inappropriate use of medicines are frequent occurrences in many countries, particularly the developing ones. [2],[3] According to the WHO, more than half of all medicines are either prescribed and dispensed irrationally or sold inappropriately, also half of all patients prescribed medications fail to take them correctly [4] leading to poor treatment outcomes.

In Nigeria and other developing nations, researches evaluating drug utilization habits have been conducted using the WHO drug use indicators, that showed very high rates of polypharmacy, [5] overuse of antibiotics and injections, and lack of prescribing from essential drugs list. [2],[4],[6],[7],[8],[9]

This study was aimed at determining the drug utilization patterns at a regional neuropsychiatric hospital, in Benin City, Nigeria using some of the WHO core drug use indicators, and to identify other drug use grey areas such as availability of key essential medicines, to which future drug use intervention programs could be centered on.

  Materials and Methods Top

Study site

This study was conducted at a regional tertiary psychiatric facility in South-south Nigeria.

The hospital has a 220-bed capacity and serves a catchment population of about 13 million [10] people.

Ethical approval

The Ethics Committee of the hospital reviewed and approved the study protocol.

Study design

The study design employed for this study was retrospective. It was a descriptive study that utilized relevant data from the prescription records of patients seen at the Out-Patient Pharmacy Unit of the hospital, from September 2007 to August 2012. Data on some of the WHO core drug use indicators [11] and the percentage of drugs prescribed but not available (i.e., out of stock) were collected during the study.

Data collection process

Systematic random sampling was adopted in the data collection. The prescription sheets of patients seen over the study period were collected and collated chronologically and later separated according to the year of prescription. For the purpose of this study, September 2007 to August 2008 is referred to as year 1, September 2008 to August 2009 as year 2, September 2009 to august 2010 as year 3, September 2010 to August 2011 as year 4, and September 2011 to August 2012 as year 5. The total number of prescriptions over the five-year period was 108,000 with an average of 48,57,60, 60 and 75 prescriptions per day giving rise to 17 280, 20 520, 21 600, 21 600, and 27 000 prescriptions, respectively, for each year. From the 108,000 total prescriptions that was collated and classified according to the year of prescription, 3 prescriptions were selected at random by picking 1 in every 16 prescriptions for the first year, 1 in every 19 prescriptions for the second year, 1 in every 20 prescriptions for the third and fourth years, and 1 in every 25 prescriptions for the fifth year amounting to 1080 prescriptions per year and 5,400 sample prescriptions used in this study. The relevant information on the sampled prescriptions was entered into a structured data collection form. The information that were extracted from the prescriptions included: Date of prescription, age and sex of the patient, number of drugs per prescription, number of drugs prescribed by generic name, number of prescriptions with antibiotics, number of drugs prescribed from the essential drugs list, number of drugs prescribed but not available. In addition, the total numbers of each drug prescribed within the study period as well as the frequency of such prescriptions were captured using a proforma designed by the authors.

Data analysis

Extracted information from the prescription sheets were entered into the data collection form and sorted with the aid of Microsoft Excel 2007 and summarized as mean and frequencies. The prescribing indicators were calculated using the WHO guideline, including average number of drugs per encounter, percentage of drugs prescribed by generic name or from essential drugs list, and percentage of encounters during which an antibiotic was prescribed.

Average number of drugs per encounter was calculated by dividing the total number of different drug products prescribed by the total number of encounters surveyed. Percentage of drug prescribed by generic name was determined by dividing the number of drugs prescribed by generic by the total number of drugs multiplied by 100. Percentage of encounter with an antibiotic prescribed was calculated by dividing the number of patient encounters during which an antibiotic was prescribed by the total number of encounters surveyed multiplied by 100. Percentage of drugs prescribed from essential drugs list was determined by dividing the total number of products prescribed from the hospital's formulary by the total number of drugs prescribed multiplied by 100. Percentage of drugs prescribed but not available was determined by dividing the number of encounters during which at least a drug was out of stock by the total number of encounters multiplied by 100.

The Drug Utilization 90% (DU 90%) segment shows the number of drugs that account for 90% of all the drugs used in that facility and comprises the drugs whose percentage adds up to 90.

The DDD/1000 inhabitants/day which provides a rough estimate of the proportion of the study population treated daily with a particular drug or group of drugs was calculated using the Anatomic Therapeutic Chemical (ATC) classification and Defined Daily Dose (DDD) assignment as given by WHO collaborating center for drug statistics methodology Oslo, Norway. [12]

  Results Top

A total number of 5,400 prescriptions were used to assess the pattern of drug utilization in this study. As shown on [Table 1], more than half of the prescriptions; 2833 (53%) were for females.
Table 1: Patient demographics

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The majority of the prescriptions; 3836 (71%) were for adults aged 18-49 years while 584 (10.81%) prescriptions did not have any age information.

The pattern of prescription revealed that an average of 2.88 drugs were prescribed per encounter, 94.38% of the drugs were prescribed by their generic names. The percentage of encounters with antibiotics prescribed was 3.2% while 99.2% of all the drugs were prescribed from the essential drugs list [Table 2].
Table 2: Prescribing pattern, based on WHO core drug use indicators[11]

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Out of the 5400 prescriptions encountered, 3826 (70.85%) had all the drugs prescribed available in the hospital pharmacy, whereas at least a drug was out of stock in 1574 (29.15%) prescriptions [Table 3].
Table 3: Drug availability

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The drugs whose utilization accounted for about 90% of the entire drug use (DU 90%) include haloperidol, amitriptyline, benzhexol, trifluoperazine, chlorpromazine, and carbamazepine. The DDD/1000 inhabitants/day for each drug as well as the actual number of population on the average that consume each drug daily is also shown on [Table 4].
Table 4: Utilization of psychotropic drugs expressed as percentages, DDD/1000 inhabitants/day and the actual number of population

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Haloperidol was the most utilized drug in the setting with a DDD/1000 inhabitants/day of 5 and about 28 patients being placed daily on this drug while the least utilized drug was paroxetine with the DDD/1000 inhabitants/day of 0.001 and about 0.007 patients being on the drug daily.

  Discussion Top

Prescriptions reflect physician's attitude towards the disease being managed, training and drug availability, as well as the nature of the prevailing health care systems. [13] Using the WHO indicators for rational drug use, this study provides insight into the prescribing practices at the Federal Neuropsychiatric Hospital, Benin City and has shown areas that need improvement.

Whereas the WHO guidelines on rational use of drugs in the region recommends a range of 1.6-1.8 drugs per encounter, [11] an average of 2.88 drugs were prescribed per encounter by clinicians in this facility. Over 50% of the prescriptions had at least 3 drugs. However, high values of 3.3 and 3.5 were in reports from Northern Nigeria, [14],[15] and even higher values of 3.99 and 4.4 were reported from Ilorin [16] and Benin-City. [13] An earlier report by Hogerzeil and colleagues showed much lower values of 1.3 and 2.2 for Bangladesh and Lebanon, respectively. [17]

The number of drugs taken has a direct relationship with the number of incidence of new hospital admissions per year due to adverse drug reactions, inappropriate medication use, and mortality. [18],[19] Drug-food interactions and therapeutic duplication errors are some of the other problems associated with polypharmacy.

Prescribing all drugs by generic names is the recommendation of the WHO. The high level of generic prescription observed in this study; (94.38%) is a good trend. Increased generic prescribing will reduce the cost of medications and promote medication adherence. Similarly, high values of 75.0% and 99.8% of generic prescribing were reported by studies in Bangladesh and Cambodia [20] though lower figures have been reported previously in Nigeria [2],[21] Ghana, [22] Lebanon, and Nepal. [23] In the United Arab Emirates, a much lower value of 4.4% has been reported. [23]

The average percentage of encounters with antibiotics found in this study was 3.2%. This value is lower than the WHO reference point (20.0-26.8%) [11] and even much lower than the earlier reports in Nigeria [12],[14],[16] Nepal, [24] Malawi, Indonesia, Bangladesh, and Tanzania. [25] This low antibiotic use is also a pointer to the relative rational prescribing practiced in this facility, and it could also be attributable to the fact that the center is a specialized facility and, therefore, most patients with some other physical ailments that would warrant the use of antibiotics are appropriately referred to other health care facilities.

Percentage of drugs prescribed from the essential drug list (99.2%) was higher than the average value of 84.60% recorded by Melinda et al. [26] from his review of previous studies in developing countries. Also, the result was higher than the value from studies by Guvon et al. [27] (16%) and Hazra et al. [28] (45.70%) but very similar to the result of Babalola et al. [29] (94.16%), Otoom et al. [30] (93%), and Bosu et al. [31] (97%).

A possible explanation for the high percentage of prescriptions from the Essential Drug List is the availability, in all the hospital consulting rooms, of the hospital drug bulletin, which was adapted from the Essential Drugs List.

The most utilized drugs in the facility studied that fall within the DU 90% segment, i.e., the drugs whose use accounted for about 90% of all the drugs used in the study site [Table 4], included: Amitriptyline (22.3%), trifluoperazine (20.3%), haloperidol (15.5%), chlorpromazine (15.2%), benzhexol (12.6%), and carbamazepine (7.9%). However, haloperidol was found to be the most prescribed drug because, out of about 60 patients seen in the OPD pharmacy daily, 28 (46.7%) of them had haloperidol on their prescriptions. As reported in an earlier study, [32] this study identified a gradual but steady decline in the use of typical antipsychotics as well as anticholinergics while the use of atypical antipsychotics such as olanzapine and risperidone is on the increase.

In about 70% of the prescriptions encountered, all the drugs prescribed were available in the hospital pharmacy. This is, however, lower than that reported from a study conducted in northern Nigeria where there was about 91.7% drug availability at the facility studied. [21]

  Conclusion Top

The study found that the prescription patterns at the hospital studied were not in conformity with the WHO guidelines. Polypharmacy is still commonly practiced at the study site. There is a need to introduce interventional strategies geared towards improving the prescribing practices of the prescribers in this facility.

The most utilized psychotropic drug at the study site was haloperidol, accounting for about 46.7% of all the drugs prescribed daily.

The level of availability of the key essential drugs in the facility was poor.

Limitations of the study

The prescriptions used in assessing the pattern of prescription were those of the patients who purchased their medications from the hospital; therefore, the result of this research might not be generalizable to patients who prefer to purchase their drugs outside the hospital. In addition, this study was conducted with the outpatient prescriptions in one institution; therefore, the result might not apply to outpatients in other federal psychiatric hospitals.

  References Top

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  [Table 1], [Table 2], [Table 3], [Table 4]


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