SN6 SHORT NOTE 5M ★ High-yield

Define essential medicines. Describe the criteria for selection and the principles of rational prescribing.

Pharmacology · 2nd Professional — Para-Clinical

Definition

Essential medicines are those that satisfy the priority health care needs of the population, selected with regard to disease prevalence, evidence of efficacy and safety, and comparative cost-effectiveness.

The WHO Model List was first published in 1977 and is revised every two years; India has its own National List of Essential Medicines (NLEM)
They should be available at all times, in adequate amounts, in the appropriate dosage form, of assured quality, and at a price the individual and the community can afford

Criteria for Selection

Adequate evidence of efficacy and safety from clinical studies
Relevance to the pattern of prevalent disease in that population
Favourable cost-effectiveness — total cost of treatment, not merely the price per tablet
Single compounds are preferred to fixed-dose combinations, unless the combination has a proven advantage in efficacy, safety or adherence
Adequate stability and availability under local storage conditions
Where two drugs are similar, the one with better pharmacokinetics, local manufacture or established experience is chosen

CLINICAL PEARL

The essential medicines concept is about selection, not restriction. It does not forbid other drugs; it identifies the limited set that will meet most of a population’s needs, so that procurement, training, storage and prescribing can concentrate on getting those few consistently right. A short list reliably supplied does far more good than a long list intermittently available.

Rational Prescribing

Requirement	Meaning
The right drug	Appropriate to the diagnosis, with proven efficacy
For the right patient	Allowing for age, pregnancy, comorbidity, renal and hepatic function, allergies and other drugs
In the right dose	Adjusted for weight and organ function
By the right route	Oral wherever it will serve
For the right duration	Long enough to work, short enough to avoid harm
At the right cost	Affordable to the patient, or the prescription will not be filled
With the right information	The patient must understand what to take, when, why, and what to watch for

Irrational Prescribing

Polypharmacy — more drugs than necessary; the risk of interaction rises steeply with number
Inappropriate antibiotic use — for viral illness, of unnecessarily broad spectrum, or for too short a course; the principal driver of antimicrobial resistance
Irrational fixed-dose combinations — a widespread problem in India, where many combinations lack any rationale and prevent independent dose adjustment; a large number have been banned
Injections where oral treatment would serve — more expensive, and carries the risk of blood-borne infection
Prescribing by brand rather than generic name, which raises cost without benefit
Use of drugs of unproven efficacy, and prescribing driven by promotion rather than evidence

Applied Aspects

Prescribe by generic name — it reduces cost, avoids confusion and permits substitution; this is now required of government doctors in India
The P-drug (personal drug) concept — each prescriber develops a small personal formulary of drugs they know thoroughly, and uses them well rather than using many drugs poorly
Price control and the Jan Aushadhi scheme improve affordability in India; the cheapest effective drug is the one the patient will actually take
Write legibly and completely — drug name, strength, dose, frequency, route and duration; illegible and ambiguous prescriptions are a documented cause of fatal error, and abbreviations such as "U" for units have killed patients
Antimicrobial stewardship — culture before starting where possible, de-escalate on the result, and stop at the right time; resistance is a collective problem created by individual decisions
Review and stop drugs regularly — every long-term prescription should have to justify its continuation

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