Introduction

Rational drug prescribing is defined as the use of the least number of drugs to obtain the best possible effect in the shortest period and at a reasonable cost₁. Measurement of drug use in health facilities not only describes drug use patterns and prescribing behaviour₂ but also helps in the identification of factors responsible for the practice of polypharmacy and the problems associated with it. Setting standards and assessing the quality of care through performance review should become part of everyday clinical practice₃. The study of prescribing patterns seeks to monitor, evaluate and if necessary, suggest modifications in prescribing patterns so as to make medical care rational and cost effective.

Medical audit oversees the observance of standards of medical care at all levels of the health care delivery system₄. It is also defined as the evaluation of medical care in retrospect through analysis of prescriptions or clinical records; to provide the full benefits of medical knowledge effectively and rationally.

Psychotropic medications are widely prescribed₅ and the utilization of psychotropic drugs is a topic of increasing interest. However data on the utilization of psychotropic drugs are lacking in Nepal, particularly western Nepal. Therefore the present study was carried out in the psychiatric out-patient department of the Manipal teaching hospital, a tertiary care hospital in Pokhara, western Nepal.

Materials and Methods

All the outpatients attending the psychiatric out-patient department (OPD) over a 45 day period (from 16.06.01 to 31.07.01) were covered in the study. The method of duplicate prescriptions was used for analysis. The information in the prescriptions was then used to complete a customised proforma. The following information was recorded: name, hospital number, age, sex, diagnosis (patient information); drug names, quantity prescribed, duration of prescription (drug information). The cost of the drugs prescribed in each prescription was calculated using the price list made available from the hospital pharmacy.

The patients were classified according to sex and were also divided into six age groups. The frequency of prescribing was calculated for the sexes and for the different age groups separately. Prescribing frequency was expressed as a percentage of the number of times a particular drug/drug category was used in a particular age/sex category to the total number of patients in the particular age/sex category.

We studied the percentage of drugs prescribed in the psychiatric OPD which were from the essential drug list of Nepal₆. The percentage of drugs prescribed from the WHO list of essential drugs were also studied₇. Further, the percentage of drugs prescribed by generic name and the percentage prescribed by brand names were also noted. The number of combination preparations and the average cost of drugs per prescription were also calculated.

Results

During the study period, 239 patients were seen in the psychiatric OPD and a total of 407 drugs were prescribed. 115 male patients (48.12%) and 124 female patients (51.88%) attended the OPD during the study period. The average number of drugs per prescription for the male patients was 1.55 0.79 (mean SD) and for the female patients the average number was 1.89 0.81. Our findings confirm the results of earlier studies₈,₉ that women patients were prescribed more psychotropic drugs than men. However, the difference was not statistically significant (Z value = 1.38).

Somatoform disorders were the most common complaint among the patients attending the psychiatry OPD (n=63). The other common complaints were anxiety (n=34) and depression (n=29). Mixed presentations of anxiety and depression were also seen.

The number of drugs per prescription is shown in table 1. Majority of the patients (86.19%) received less than 3 drugs per prescription. The drugs were generally prescribed for a time duration of 15 days. The average cost of drugs per prescription was 84.09 69.52 Nepalese rupees (52.56 43.45 Indian rupees).

Figure 1

Table 1. Incidence of polypharmacy

120 of the total of 407 drugs prescribed (29.48%) were from the essential drug list of Nepal6 and the same number were from the WHO list of essential drugs7. Only 29.7% of the drugs were prescribed by generic names. 44 of the total of 407 drugs prescribed were combination preparations.

Table 2 shows the prescribing frequency of the different categories of psychotropic medications versus sex. The prescribing frequency of the tricyclic antidepressants ( 2 value = 5.96) and selective serotonin reuptake inhibitors ( 2 value = 8.7) were significantly more for female patients.

Figure 2

Table 2: Prescribing frequencies of selected drug categories

2= 5.96 p<0.05, 2=8.7 p<0.05

Majority of the patients attending the psychiatry OPD [140(58.58%)] were below the age of 36 years. The most commonly prescribed categories of drugs in the psychiatry OPD were in descending order of frequency: tricyclic antidepressants (TCAs), anxiolytics/sedatives and selective serotonin reuptake inhibitors (SSRIs). Regarding individual drugs the most commonly prescribed antidepressants were the SSRI Fluoxetine (41 patients) and the TCA Doxepin (33 patients). Analysis of prescribing frequency versus age is shown in Table 3. No clear trends of differences in prescribing frequency with age were observed.

Figure 3

Table 3: Age-wise prescribing frequency for chosen drug categories

Discussion

A prescription may be taken as a reflection of the physicians' attitude to the disease and the role of the drug in its treatment. It also provides an insight into the nature of the health care delivery system₁₀. The role of the psychiatrist in ensuring compliance to the drug treatment cannot be over-emphasised. The capacity of the therapist to manage and control the treatment is an essential part of the therapeutic relationship between the doctor and the patient₁₁.

The average number of drugs per prescription in an audit is an important index of the scope for review and educational intervention in prescribing practices. This is especially important in psychiatry as studies8,₁₂ have shown that polypharmacy was common and psychotherapeutic drugs have been over-prescribed and misused. The average number of drugs per prescription in our study (n=1.75) is on the lower side. Only 13.72% of the patients received 3 or more drugs as compared to 40% reported from an Italian study₁₃.

The cost of the prescription is an important variable in determining compliance to the treatment, especially in a developing country like Nepal. Compliance is a variable which must be taken into account in the interpretation of the results of a given treatment. This is especially true in psychiatry because of the long duration of treatment and the high level of non-compliance (20-50%)11. The average cost per prescription in our study was 84.09 Nepalese rupees. As the drugs were prescribed for an average duration of 15 days the daily cost of the medications was 5.6 Nepalese rupees which is affordable by the majority of the patients.

Previous studies9,₁₄ have suggested that female patients receive more psychotropic medications than male patients. Female patients were significantly more likely to be prescribed psychotropic drugs of all types from a female physician than from a male one9. However, information on patient diagnosis and severity of symptoms were not taken into account. In our study female patients were prescribed, on an average, more psychotropic drugs than male patients but the difference was not statistically significant. This is in agreement with a study carried out in Finland₁₅ where no gender differences were found after controlling for mental problems. Females were prescribed significantly more antidepressants than males and this could be explained by the higher incidence of depression and somatoform disorders in females.

Antidepressants were the most commonly prescribed class of psychotropic drugs in our study. This holds true across the different age groups and also across both the sexes. In most of the studies reported in the literature13,15,₁₆ benzodiazepines were the most frequently prescribed class of psychotropic drugs. However, a longitudinal study carried out in the United States reports that the use of hypnotic drugs, previously the most frequently prescribed category, have declined and are now surpassed by antidepressant drugs5. Tricyclic antidepressants remain the most frequently prescribed class of antidepressants and this is in consonance with other studies13,₁₇.

10.81% of the drugs used were combination preparations and 29.48% of the drugs prescribed were from the essential drug list. 70.3% of the drugs were prescribed by brand names. These are issues for concern and can be redressed to some extent by prescriber education. Still the reasons often cited for the use of such combination preparations namely convenience, improvement in compliance, lower cost hold true even in our OPD.

The value of medical audits for generating and testing hypotheses on inappropriate prescribing has resulted in educational interventions to improve prescribing patterns₁₈,₁₉. The information can be used to develop adverse drug reaction monitoring programs also. Polypharmacy increases the risk of drug interactions and errors of prescribing. Fortunately in our study the incidence of polypharmacy was low (1.75 drugs per prescription).

Further studies in patient compliance with treatment and the dropout rate from psychiatric treatment are urgently required. The present study could serve as a framework upon which further studies in prescription audit of psychotropic drugs can be launched to investigate the scope for improvement in prescribing practices.

Correspondence to

DR.P.Ravi Shankar Department of Pharmacology Manipal College of Medical sciences P.O.Box 155 Pokhara, Nepal. E-mail: mcoms@mos.com.np pathiyilravi@rediffmail.com