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PH10.8 | PH10.8 | Essential Medicines and Formulary Choices — SDL Guide — SDL Guide (Part 2)
Over-the-Counter Drugs: Classification and Safe Use
Over-the-counter (OTC) drugs are medicines that can be purchased without a physician's prescription. In India, OTC status is determined by which drugs are NOT listed under Schedules H, H1, or X of the Drugs and Cosmetics Act — the absence of scheduling, rather than an explicit OTC designation, determines OTC availability. This creates a somewhat ambiguous regulatory situation compared to some other countries with explicit OTC approval pathways.
The criteria that make a drug suitable for OTC availability are:
1. Self-diagnosable condition: the condition being treated can be identified by the patient without professional diagnosis (e.g. common cold, mild headache, antacid use for heartburn)
2. Acceptable safety profile in self-use: the drug has a wide therapeutic index and low risk of serious adverse effects with self-dosing (e.g. standard-dose paracetamol is safe for self-use; high-dose NSAIDs carry GI/renal risk)
3. Low abuse or dependence potential: the drug is not likely to be misused for non-medical purposes
4. Manageable interaction profile: the drug does not have interactions so serious that self-use without prescriber review is dangerous
Common OTC drug categories in India include: mild analgesics/antipyretics (paracetamol at standard doses), antacids (aluminum hydroxide, magnesium trisilicate), antihistamines for mild allergic symptoms (chlorphenamine, cetirizine), oral rehydration salts, vitamins, topical antiseptics, and some cough preparations.
The prescriber's role in OTC education: As a physician, you will frequently be asked about OTC drugs by patients managing their own mild conditions. Your responsibilities include:
- Advising on appropriate OTC choices for self-treatable conditions
- Warning about OTC interactions with prescribed medicines (e.g. aspirin + warfarin; antacid + absorption of other medications)
- Recognising when a patient's OTC use is masking a condition requiring medical evaluation (e.g. frequent antacid use for 'indigestion' that is actually peptic ulcer disease)
- Educating patients on safe OTC use, particularly regarding paracetamol dose limits (maximum 1g per dose, 4g per day in adults; lower in patients with hepatic disease or alcohol use)
SELF-CHECK
A pharmaceutical company proposes an FDC of Atenolol 50 mg + Amlodipine 5 mg as a once-daily antihypertensive. Which criterion BEST determines whether this FDC is rational?
A. A) Both are antihypertensives, so the combination automatically qualifies as rational
B. B) The fixed 50 mg:5 mg ratio is clinically appropriate for the majority of hypertensive patients who need both drugs simultaneously
C. C) The FDC is cheaper than buying the components separately
D. D) Both drugs are on the NLEM individually, so their combination is automatically listed
Reveal Answer
Answer: B. B) The fixed 50 mg:5 mg ratio is clinically appropriate for the majority of hypertensive patients who need both drugs simultaneously
B is correct. A key rationality criterion for an FDC is whether the fixed-dose ratio is clinically appropriate for the majority of patients who need both drugs. In hypertension, atenolol and amlodipine are both effective, but their dose titration needs may differ between patients — some may need amlodipine 10 mg but only atenolol 25 mg. If the fixed ratio prevents appropriate dose titration for a significant proportion of patients, the FDC is irrational regardless of whether both components are individually useful. NLEM listing of components does not automatically endorse the FDC; cost alone does not determine rationality; and two drugs being in the same class does not make their combination rational.
Choosing Essential Medicines: A Step-by-Step Approach
Selecting an essential medicine for a given patient and condition is a practical skill that integrates the P-drug framework with the essential medicines concept. The steps below describe how to move from a clinical problem to a formulary-appropriate drug choice systematically.
Step 1 — Define the clinical problem and specify the therapeutic objective. (This mirrors the first two steps of the P-drug method.) What exactly are you treating? What outcome do you need the drug to produce in this patient?
Step 2 — Identify the relevant NLEM category. Look up the condition or drug class in the NLEM. The 2022 NLEM organises drugs by therapeutic class and level of healthcare (primary, secondary, tertiary) — knowing the level guides whether the drug should be available at a PHC, district hospital, or tertiary centre.
Step 3 — Evaluate NLEM options against P-drug criteria. For each NLEM candidate drug for this problem, apply the four criteria: efficacy (does the NLEM listing imply proven efficacy?), safety (are there patient-specific contraindications?), suitability (is the formulation available and appropriate for this patient?), cost (is it price-controlled under DPCO; what is the patient's actual out-of-pocket cost?).
Step 4 — If no NLEM drug is suitable, document the reason. Non-NLEM prescribing should be the exception and require explicit justification — for example, a patient with a genuine allergy to the NLEM first-line drug, or a condition requiring a drug not yet listed (newer medications added to the global WHO EML but not yet to NLEM 2022). This documentation protects the prescriber and generates data for formulary review.
Step 5 — Check for an irrational FDC. Before prescribing an FDC, confirm it meets the four rationality criteria. If the clinical need can be met by separate components with better dose flexibility, prefer separate prescribing.
This approach not only benefits the patient but generates the information needed to improve formularies over time — prescribers who consistently cannot find an appropriate NLEM drug for a common condition are providing implicit data that the NLEM needs updating for that condition.
Evaluating Formulary Choices: Applying and Appraising the NLEM
The NLEM is a living document — it is revised periodically, and the criteria for revision are precisely the evidence-quality standards described above. Understanding how to evaluate and challenge a formulary choice is as important as knowing how to use the formulary.
Applying the NLEM in practice:
Hospital formularies in India typically mirror or derive from the NLEM with local additions based on the patient population, disease burden, and specialist services available. When you prescribe, knowing whether a drug is on the hospital formulary (and the NLEM) affects: availability (will the pharmacy have it?), cost (is it price-controlled?), and regulatory standing (have the procurement channels been validated?).
Challenging a formulary choice:
A formulary is not infallible. Legitimate grounds for challenging a formulary listing include:
- New evidence that a listed drug has greater harm than previously recognised (e.g. a post-marketing safety signal)
- Emergence of a new drug that is demonstrably superior on efficacy or safety at comparable cost
- A listed drug that is no longer meeting the local resistance or epidemiological profile
The process for raising a formulary challenge should follow institutional governance — typically a written submission to the pharmacy and therapeutics committee (P&T committee), supported by the evidence.
Equity and access dimensions:
The essential medicines framework is explicitly an equity instrument. NLEM drugs, being price-controlled, are more likely to be affordable for patients in India's predominantly out-of-pocket health financing system. Prescribing an equivalent non-NLEM branded product at several times the price without clinical justification imposes an unnecessary cost burden on the patient and their family. This is not merely an economic observation — it has direct consequences for treatment adherence, completion of therapy, and health outcomes, particularly in rural and lower-income populations.
Practical skill: comparing an NLEM drug with a promotional alternative:
When a pharmaceutical representative promotes a non-NLEM product as superior to an NLEM drug for the same indication, the prescriber should ask: (1) Is the evidence for superiority based on clinical outcomes or surrogate endpoints? (2) Has the evidence been reviewed by any independent body (WHO EML committee, national expert committee)? (3) What is the NNT for the claimed benefit, and what is the NNH for the additional risks? (4) What is the absolute cost difference, and is the benefit worth that cost for this patient?
CLINICAL PEARL
Prescribing a non-NLEM drug requires a reason. The NLEM is a systematic expert judgment that a drug offers the best benefit-risk-cost profile for Indian healthcare. When you choose a non-NLEM alternative for the same indication without clinical justification, you are implicitly overriding that expert judgment — and usually at greater cost to the patient. The clinical pearl is not 'always use NLEM drugs' but 'always know WHY you are not using one when you have a choice.' In prescribing audits and medicolegal contexts, unexplained non-NLEM prescribing when NLEM alternatives existed is difficult to justify.
SELF-CHECK
A patient requires treatment for an uncomplicated peptic ulcer. The hospital formulary lists both omeprazole (NLEM, generic, low cost) and a branded pantoprazole-domperidone FDC (non-NLEM, higher cost). You know the patient has no nausea or motility symptoms. What is the BEST prescribing choice and its primary justification?
A. A) The FDC — it provides broader coverage and prevents nausea that may develop
B. B) Omeprazole — it is the NLEM choice; there is no clinical indication for domperidone in this patient, so the FDC is irrational here
C. C) Either is acceptable — both are proton pump inhibitors
D. D) Branded pantoprazole alone — more effective than omeprazole for peptic ulcer
Reveal Answer
Answer: B. B) Omeprazole — it is the NLEM choice; there is no clinical indication for domperidone in this patient, so the FDC is irrational here
B is correct. Adding domperidone to a proton pump inhibitor is only indicated if the patient has nausea, vomiting, or gastroparesis — there is no indication here. The FDC therefore fails the first rationality criterion (both components must be clinically indicated for the same patient). Omeprazole is an NLEM drug with well-established efficacy for peptic ulcer disease. Clinical equivalence of PPIs for peptic ulcer healing means the NLEM choice at lower cost is preferred. 'Broader coverage' is not a valid indication for using a drug the patient does not need.
Self-Assessment: Essential Medicines and Formulary Reasoning
Apply your learning through the following structured exercises before the next session.
Exercise 1 — EML criteria application:
A new oral antifungal for dermatophytosis is proposed for the NLEM. It costs three times as much as the existing NLEM drug griseofulvin, but it has a shorter treatment duration (2 weeks vs 6–8 weeks). What additional information would you need to evaluate whether it meets the 'comparative cost-effectiveness' criterion for EML listing?
Expected response: You need: (1) the total treatment cost comparison (3× daily cost for fewer days — what is the total course cost vs griseofulvin?); (2) efficacy data — cure rates, relapse rates, time to cure; (3) safety and adherence comparison — does the shorter course improve actual completion rates enough to produce better real-world outcomes?; (4) whether a shorter duration actually produces non-inferior mycological cure rates vs the longer griseofulvin course.
Exercise 2 — FDC appraisal:
A fixed-dose combination of Metformin 500 mg + Vildagliptin 50 mg (a DPP-4 inhibitor) is available for type 2 diabetes. The promotional claim is 'better adherence and additive glucose-lowering.' Evaluate whether this FDC meets the rationality criteria.
Expected response: Rationality criteria review: (1) Are both components indicated for the same patient? — Yes, in patients with type 2 diabetes not controlled on metformin alone who require add-on therapy (both are clinically indicated simultaneously for many patients at this stage). (2) Does combined use produce better outcomes than sequential prescribing? — The fixed ratio has been validated in clinical trials and is a standard second-line combination; the 500mg:50mg ratio is a standard therapeutic combination. (3) Fixed ratio appropriate? — Yes, for patients who are on metformin 500 mg and need vildagliptin 50 mg. However, if the patient needs metformin 1000 mg with vildagliptin 50 mg, a different ratio FDC is required. (4) Cost? — the FDC should not cost more than the separate components. Conclusion: Potentially rational if dose-titration needs match the fixed ratio and cost is not higher than separate prescribing; irrational if the patient's dose requirements cannot be met by the available FDC strengths.