Criteria for Rational Prescribing
Rational prescribing should meet the certain criteria such as appropriate diagnosis, indication, drug, patient, dosage, duration, route of administration, information and monitoring :
To achieve correct diagnosis one has to depend on the clinical features and laboratory investigations Clinical feature is the most important criterion. For example, we can easily diagnose a case of pneumonia in children by counting the respiratory rate as well as indwelling chest without the help of any laboratory investigation which is seldom available in the rural areas. However, sometimes laboratory investigation may confuse making accurate diagnosis. So, if someone knows the clinical feature of a diseases then he can easily diagnose and treat the cases rationally and thereby avoiding the misuse of money, time and labor.
It is necessary to know whether drug is actually necessary or not. The decision to prescribe drug is entirely based on medical rationale and that drug therapy is an effective and safe treatment. For example, most of the diarrhea in children is due to viral causes e.g. Rota virus. In that case, no drug is necessary. On the other hand, if we diagnose a case of diarrhea as cholera based on epidemiological aspect, then antibiotic should be prescribed.
The selection of drug is based on efficacy, safety, suitability, cost considerations, and easy availability. For example, a child with a history of cholera must be treated with erythromycin, which is safe and effective. Here, tetracycline although is indicated, it should be avoided because the patient is a child.
While considering the patient one should consider about his/her sensitivity to drug, totally contraindicated or may be used cautiously. For example, it is better to avoid the use of drug during pregnancy and lactation. However, a drug may be prescribed considering risk benefit ratio of the mother and the fetus. In most cases the drug should be provided where no contraindications exist and the likelihood of adverse effect is minimal.
Doses should be considered when the patient is either a child, geriatric, or having a history of concomitant diseases such as hepatic or renal impairment. It should be reduced in children or geriatric patient due to low metabolizing capacity of the drug and less function of the vital organs. For example, digoxin must be administered at a loading dosage when the plasma concentration of free drug is very low for therapeutic response in usual dosage as it is a highly protein bound drug. So, loading dosage of digoxin is helpful for obtaining immediate effect. Anti-biotic especially penicillin given in a loading dosage initially is higher for greater bioavailability.
When the oral route is appropriate for a patient, then intravenous route should not be prescribed as because, it will be expensive, having more adverse 10 days. However, in case of cholera tetracycline should be used for period of 3 days. If somebody use tetracycline in cholera for 7 to 10 days that will be irrational.
Appropriate route of administration:
When the oral route is appropriate for a patient, then intravenous route should not be prescribed as because, it will be expansive, having more adverse effects, and irrational. In many occasions diazepam is given parenterally but oral drug is indicated.
The patient should be provided with relevant, accurate, important, and clear information regarding his /her condition and the medications that are prescribed.
The anticipated and unexpected effects of medications should be appropriately monitored. For example, in case of tissue transplantation the monitoring of cyclosporine A is vital for the effectiveness of treatment (tough level should be less than 200 µg/ml).