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clinmed/2002050004v1 (May 16, 2002)
Contact author(s) for copyright information
Title: Prescribing patterns in medical outpatients
Authors and qualifications:
Ravi Shankar P. M.D.
Department of Pharmacology
Manipal College of Medical Sciences
Pokhara, Nepal.
Praveen Partha D.N.B.
Department of Medicine
Manipal Teaching Hospital
Pokhara, Nepal.
Nagesh Shenoy M.Pharm.
Department of Pharmacy
Manipal Teaching Hospital
Pokhara, Nepal.
Department and institution where the work was carried out:
Department of Pharmacology Department of Medicine
Manipal College of Medical Sciences Manipal Teaching Hospital
Corresponding author:
DR.P.Ravi Shankar
Department of Pharmacology
Manipal College of Medical Sciences
P.O. Box 155
Deep Heights
Pokhara, Nepal
Fax:00977-61-22160
E-mail: mcoms{at}mos.com.np
pathiyilravi@rediffmail.com
Summary:
A drug utilisation review was carried out in the medical out-patient department of the Manipal teaching hospital, a tertiary care hospital in Pokhara, western Nepal to determine the prescribing frequency of commonly used drugs. An attempt was made to relate prescription data to age and sex of the patients. 530 prescriptions were analysed and the mean ± SD drugs per prescription was 2.15 ± 1.71. 67.4% of the drugs were prescribed by brand names and only 39.56% of the drugs prescribed were from the WHO essential drug list. The average cost of drugs per prescription was 2.75 ± 2.21 US dollars. The frequency of prescribing of antiulcer drugs, antibiotics, antiasthma drugs, antihypertensives and analgesics were 24.15% (n=128), 23.96% (n=127), 20.56% (n=109), 19.81% (n=105) and 15.09% (n=80) respectively. This study reveals a lot of scope for educating the prescribers to improve prescribing practices.
Introduction:
Irrational prescription of drugs is a common occurrence in clinical practice.1 The cost of such irrational drug use is enormous in terms of both scarce resources and the adverse clinical consequences of therapies that may have real risks but no objective benefits. This is especially true in case of countries such as Nepal with a difficult topography that makes access to health care delivery systems difficult.
The assessment of drug utilisation is important for clinical, educational and economic reasons.2 Various factors influence the prescribing behaviour of clinicians and to change the behaviour it is necessary to understand the reasons behind it.3 It is necessary to define the prescribing pattern and to target the irrational prescribing habits for sending a remedial message.4
Drug Utilisation Reviews (DURs) are useful for obtaining information about drug usage patterns and for identifying high cost drugs, which are of economic interest.5 Data about drug usage patterns in western Nepal are particularly lacking. Keeping these facts in consideration the present study has been planned to define the pattern of drug use in the medical out-patient department at the Manipal teaching hospital, a tertiary care hospital in Pokhara, western Nepal. An attempt was also made to associate prescription data with two demographic characteristics, e.g. age and sex.
Materials and methods:
All the prescription files from the medical OPD of the Manipal teaching hospital over a nine day period (01.07.01 to 09.07.01) were taken for analysis. The number of drugs prescribed in each prescription was taken into account to calculate the incidence of polypharmacy. The data from the records were entered into a specially designed proforma. The following parameters were recorded for each prescription: patient's name, age, sex, hospital number and diagnosis (patient information); drug name, dose, frequency and duration of prescription (drug information). The cost of the drugs in the prescription was calculated by using a list of the prices of individual drugs obtained from the hospital pharmacy.
The patients were classified by sex and then divided into six age groups. The frequency of prescribing was calculated for each age group and for males and females separately. Prescribing frequency was expressed as a percentage of the prescription of the individual drug/drug class in a particular age/sex category to the total number of patients in the particular age/sex category.
We studied the percentage of the prescribed drugs which were from the essential drug list of Nepal.6 Further whether the drugs were prescribed using generic names or brand names was also studied. The number of combination preparations and the share of the five most commonly prescribed drug categories in the total cost of drugs were also noted.
Results:
Five hundred and thirty prescriptions were analysed during the study period. The mean ± SD number of drugs per prescription was 2.156 ± 1.71 and the range was from 0-10. The drugs were prescribed by brand names in the case of 710 drugs (67.36%) and by generic names in 344 cases (32.64%). 71 of the 1054 drugs prescribed were combination preparations and 52.69% of the drugs prescribed were from the essential drug list of Nepal.6 39.56% of the drugs prescribed in the medical OPD during the period of the study were from the WHO essential drug list.7 The discrepancy in the number of drugs between the two lists was mainly due to the non-inclusion of drugs like ranitidine, omeprazole and enalapril in the WHO essential drug list.
The number of drugs per prescription is shown in Table 1. 211 patients (39.8 %) received only 1 drug while 169 patients (31.89%) received a total of 2 drugs.
The age distribution of the patients is shown in Table 3. 44.91% of the patients attending the medical OPD were below the age of 36 years. 270 male patients (50.94%) attended the medical OPD during the study period as against 260 female patients during the same time period. The duration of drug prescription was less than 7 days in 17.36% of the patients and between 7-13 days in 25.1% of the patients. Out of the total of 1054 drugs prescribed in the medical OPD during the study period the 10 most commonly prescribed drug categories in the decreasing order of prescribing frequency were: antiulcer drugs, antibiotics, antihistamines, psychotropic drugs, oral antidiabetics, vitamins and anthelminthics.
Table 2 shows the analysis of the prescribing frequency of the 6 most common drug categories versus sex. There were no significant differences in the prescribing frequencies of the drug categories between males and females except that of antihistamines which was significantly higher in males.
The average cost of drugs per prescription was 200.78 ± 161.39 Nepalese rupees (5.87 ± 4.66 US dollars). Antiasthmatic drugs and antibiotics accounted for a large proportion of the total cost. The average cost of drugs per prescription in asthma and COPD patients was 428.32 ± 340.32 Nepalese rupees (5.87 ± 4.66 US dollars). The five most commonly prescribed drug categories namely antiulcer drugs, antibiotics, antiasthma drugs, antihypertensives and analgesics together accounted for 52.52% of the total cost incurred on drugs during the study period.
Table 3 shows the prescribing frequencies of selected drug categories versus age. The prescribing frequency of antibiotics showed a decline with increasing age. The prescribing frequency of antiulcer drugs remained constant with increasing age. There was a declining trend in the prescribing of analgesics with increasing age and there was a substantial increase in the prescribing frequency of antihypertensives with increasing age.
Table 4 shows the prescribing frequency of individual drugs. Omeprazole was the most commonly prescribed antiulcer drug. Amoxicillin, beclomethasone and amlodipine were the most commonly prescribed antibiotics, antiasthma drugs and antihypertensives respectively.
Discussion:
A prescription by a doctor may be taken as a reflection of physicians’ attitude to the disease and the role of drug in its treatment. It also provides an insight into the nature of the health care delivery system.
Average number of drugs per prescription (in a prescription audit) is an important index of the scope for review and educational interventions in prescribing practices. A community-based study on prescribing patterns from India reported a mean number of 2 drugs,8 similar to our study. A hospital-based study in India has also reported a similar figure.9 However, other hospital-based studies have reported figures of 3-5 drugs per prescription.10,11 With higher figures there is an increased risk of drug interactions12 and errors of prescribing.13
We have expressed the prevalence of prescribing as the total number of prescriptions for a particular drug/drug category and also as the prescribing frequency. Prescribing prevalence studies are useful to determine the prevailing morbidity patterns.14 In our study, the high prescribing frequency of antiulcer drugs, antihypertensives and antiasthma drugs was due to the high prevalence of these disease conditions in the study population.
The average cost of drugs per prescription was 200.78 Nepalese rupees which is fairly high for a poor country like Nepal. A study of prescription compliance based on the average cost of treatment is suggested. This is important because in a developing country like Nepal, patient compliance is primarily dependent on the cost of treatment. Among the drugs prescribed in this study beclomethasone and salmeterol metered dose inhalers, beclomethasone nasal spray and cephalosporin antimicrobials are expensive drugs and patient compliance is expected to be poor for such preparations. The prescribing frequency of the antihistamine cetrizine was about ten times that of actifed, cetrizine being about three times more expensive. Therefore, the rationale for prescribing expensive medications should be made very clear when cheaper alternatives are available.
The increase in prescribing frequency of antihypertensives and oral hypoglycemic drugs with increasing age correlates with the increasing incidence of hypertension and type 2 diabetes mellitus with advancing age. Contrary to the findings of a previous study9 there was no sex variation in the prescribing of cardiovascular drugs. This suggests that the prevalence of cardiovascular diseases is not significantly different in the two sexes which is confirmed by our data. The prescribing frequency of antibiotics, antiulcer drugs and analgesics were also not significantly different among the sexes. The increased prescription of antihistamines in males reflects the increased prevalence of upper respiratory infections in males.
The most commonly used drug group was the antiulcer drugs. The prescribing prevalence of antibiotics was also high (23.93%). The excessive use of antimicrobials is similar to the reports from other developing countries.15,16 In the developing countries, bacterial infections account for much of the morbidity and mortality. This is to be expected as most of the population in the developing countries exists under conditions of poverty, inadequate medical care, poor sanitation and nutrition.17 The main causes of morbidity in Nepal are gastrointestinal and respiratory infections, enteric fever, tuberculosis and malnutrition.18 Most of the patients were prescribed the older antimicrobials and this is in keeping with the sensitivity patterns of micro-organisms in our hospital.
The use of combination preparations in our study (6.74%) was comparable to that observed in a similar study in eastern Nepal.19 21.3% of the combination preparations were for the combination of metronidazole and diloxanide furoate which was rational while most of the analgesic combinations were irrational. 67.36% of the drugs were prescribed by their brand names and this is to be actively discouraged. Vitamin preparations were commonly prescribed in the medicine OPD and constituted 3.04% of all drugs prescribed. This may be due to the use of vitamin as a placebo. Although placebo therapy is criticised as a deception,20 vitamins are often used to that end in therapeutics. However, a large proportion of the vitamins were prescribed by brand names increasing the cost of therapy.
In our study the strength, dose, frequency and duration of administration of the drugs prescribed were not mentioned in approximately 36% of them. Such omissions should be avoided in drug administration as they may seriously undermine the efficacy of treatment and increase the incidence of adverse effects. Previous studies conducted in Nepal19 and India21 also showed persistent trends towards not documenting the duration of treatment. Such documentation is much more important in case of outpatients as daily follow up and monitoring of these patients is not feasible.
The results indicate a considerable scope for improving the prescribing pattern of drugs in the medical OPD. The improvement would be facilitated by providing feedback, prescriber education and creation of a hospital formulary.
References:
Table 1 : Incidence of polypharmacy
|
No. of drugs per prescription |
No. of prescriptions |
Percentage |
|
0 |
26 |
4.9 |
|
1 |
211 |
39.8 |
|
2 |
169 |
31.9 |
|
3 |
62 |
11.7 |
|
4 |
42 |
7.92 |
|
Above 4 |
20 |
3.77 |
|
Total |
530 |
100 |
Table 2: Prescribing frequencies of selected drug categories
|
Drug category |
No. of patients ( % of population) |
|
|
Male n=270 |
Female n=260 |
|
|
Antiulcer drugs |
61(22.6) |
67(25.8) |
|
Antibiotics |
69(25.5) |
58(22.3) |
|
Antihypertensives |
53(19.7) |
52(20) |
|
Antiasthma drugs |
58(21.5) |
51(19.6) |
|
Analgesics |
39(14.4) |
41(15.8) |
|
Antihistamines |
44(16.3)* |
26(10) |
* c 2 =4.58, p<0.05
Table 3: Age-wise prescribing frequency for chosen drug categories
|
Age group (No. of patients) |
Anti-hypertensives |
Oral hypoglycemics |
Antibiotics |
Anti-TB drugs |
Antiulcer drugs |
Analgesics |
Antihistamines |
Anthelminthics |
Antiasthma drugs |
|
14-25 n=131 |
3(2.3) |
0 |
45(34.35) |
18(13.74) |
32(24.43) |
23(16.79) |
22(16.8) |
19(14.5) |
14(10.69) |
|
26-35 n=107 |
6(5.61) |
0 |
30(28.04) |
6(5.61) |
31(28.97) |
19(17.76) |
16(14.95) |
9(8.4) |
18(16.82) |
|
36-45 n=182 |
11(13.41) |
4(4.88) |
13(15.85) |
1(1.22) |
22(26.78) |
10(12.2) |
7(8.54) |
2(2.44) |
21(25.6) |
|
46-55 n=82 |
31(37.8) |
21(25.61) |
16(19.5) |
2(2.44) |
20(24.4) |
10(12.2) |
12(14.63) |
2(2.44) |
7(8.54) |
|
56-65 n=84 |
36(42.8) |
14(16.66) |
10(11.9) |
9(10.7) |
15(17.86) |
11(13.1) |
5(5.95) |
4(4.76) |
23(27.4) |
|
Above 65 n=44 |
15(3.41) |
6(13.64) |
7(15.9) |
7(15.9) |
4(9.1) |
2(4.54) |
6(13.64) |
1(2.27) |
19(43.2) |
Table 4: Prescribing prevalence of individual drugs
|
Drug |
No. of patients n=530 |
Percentage |
|
Antiulcer drugs: Omeprazole Ranitidine Famotidine |
66 31 25 |
12.45 5.85 4.72 |
|
Antibiotics: Amoxicillin Metronidazole Metronidazole and diloxanide furoate Norfloxacin |
27 18 15 9 |
5.1 3.4 2.83 1.7 |
|
Antiasthma drugs: Beclomethasone Salbutamol Deriphylline |
26 25 23 |
4.9 4.72 4.34 |
|
Antihypertensives: Amlodipine Enalapril Atenolol |
46 23 10 |
8.68 4.34 1.89 |
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