PH10.1-17 | Applied Pharmacology and Prescribing Skills — Glossary

The arithmetic difference in event rates between control and treatment arms; the denominator for calculating NNT

A complex neurobehavioral disorder characterised by compulsive drug use despite harm, impaired control, preoccupation with the drug, and neuroplastic changes in reward circuitry

The extent to which a patient's behaviour corresponds with agreed recommendations from their healthcare provider; preferred over 'compliance' because it emphasises collaboration

Programmes and practices to optimise antibiotic prescribing — choosing the right drug, dose, and duration — to maximise clinical outcomes while minimising resistance, toxicity, and cost

A potentially life-threatening syndrome following abrupt discontinuation of long-term benzodiazepines: anxiety, insomnia, tremor, and risk of generalised tonic-clonic seizures; managed by gradual tapering

India's national drug regulatory authority under the Ministry of Health; responsible for marketing approval, clinical trial regulation, and pharmacovigilance

A scoring system assessing hepatic functional reserve in cirrhosis based on bilirubin, albumin, prothrombin time, ascites, and encephalopathy; Classes A/B/C guide hepatic dose adjustment

The validated formula for estimating CrCl: [(140−age) × weight(kg)] ÷ [72 × SCr(mg/dL)] × 0.85 for females; the standard for drug dose adjustment in renal impairment

A drug evaluation criterion comparing the health outcome produced per unit cost against available alternatives for the same indication

An estimate of glomerular filtration rate calculated from serum creatinine, age, weight, and sex using the Cockcroft-Gault equation; used for renal dose adjustment

India's mandatory public registry for all clinical trials conducted in India; required for regulatory compliance and publication in Indian journals

A superfamily of liver and gut enzymes responsible for the oxidative metabolism of most drugs; highly polymorphic genes lead to variable metaboliser phenotypes

WMA ethical principles for medical research involving human subjects; mandates informed consent, independent ethics review, and primacy of participant welfare

The WHO-recommended strategy for TB treatment where a health worker observes the patient swallowing every dose; reduces non-adherence and drug resistance

A regulatory order issued by the Ministry of Chemicals and Fertilisers (India) that caps the prices of drugs listed in the NLEM

Medicines that satisfy the priority health needs of a population, selected by WHO/NLEM based on public health relevance, efficacy, safety, and comparative cost-effectiveness

A pharmaceutical product containing two or more active substances in a fixed dose ratio in a single dosage form

The documented tendency for industry-funded trials to report results more favourable to the sponsor's product than independently funded trials

A common hereditary enzyme deficiency affecting 10–15% of some Indian populations; causes haemolytic anaemia when exposed to oxidant drugs such as primaquine and dapsone

The ICH E6(R2) international quality standard for conducting clinical trials; ensures participant protection, data integrity, and regulatory compliance

Strategies that minimise the harms associated with drug use without necessarily requiring abstinence — includes naloxone provision, safe storage education, and opioid substitution therapy

The ability to obtain, understand, and act on health information; low health literacy is an independent predictor of non-adherence and poor chronic disease management

The difference in cost between two interventions divided by the difference in their effectiveness; the standard metric for cost-effectiveness analysis

The generic, non-branded name for a drug substance, assigned by WHO; the standard name for prescribing and regulatory purposes

A patient's conscious decision not to take a medication — driven by perceived lack of benefit, side-effect concerns, cost, or distrust; requires motivational intervention

India's national generic medicine programme (PMBJP) providing quality generic drugs at 50–90% below branded prices; accessible via janaushadhi.gov.in

An 8-item validated self-report questionnaire assessing medication adherence behaviour; scores <6 = low adherence; 6-7 = medium; 8 = high

A collaborative communication style for supporting health behaviour change; uses empathy, discrepancy development, and self-efficacy reinforcement; RCT evidence for adherence in chronic disease

A characteristic of drugs where the effective concentration range is close to the toxic concentration range — small deviations from the target dose produce either treatment failure or toxicity

India's national adaptation of the WHO EML, listing approximately 384 medicines as of 2022; NLEM-listed drugs are subject to price control under the DPCO

The number of patients who must receive a treatment for one to experience a specific adverse effect; mirrors NNT for benefit-risk comparison

The number of patients who must receive a treatment to prevent one adverse outcome; NNT = 1/ARR; a practical measure of clinical significance

Prescribing a drug outside its approved indication, dose, route, or patient population; legal in India but requires informed consent and clinical documentation

The use of a long-acting, orally administered opioid agonist (buprenorphine/naloxone or methadone) to treat opioid use disorder; available in India through the National AIDS Control Organisation's OSAT programme

A physiological syndrome following abrupt opioid cessation: yawning, rhinorrhoea, myalgia, agitation, diaphoresis, tachycardia, abdominal cramps; rarely fatal in otherwise healthy adults but intensely unpleasant

A validated 5-item pre-prescribing screening tool classifying patients as low, moderate, or high risk for opioid misuse based on personal and family history factors

A medicine that can be purchased without a physician's prescription; in India, determined by absence from Schedules H, H1, and X

A first-line drug systematically selected by a prescriber for a given clinical problem using WHO criteria of efficacy, safety, suitability, and cost

The regulatory-approved prescribing information document submitted and updated by the manufacturer; authoritative on approved indications and safety profile

The study of how genetic variation in an individual affects drug absorption, metabolism, response, and toxicity — enabling genotype-guided prescribing

A hospital-level committee responsible for maintaining the institutional formulary, reviewing drug additions and deletions, and promoting rational prescribing

First-in-human trial (20-80 usually healthy volunteers) evaluating safety, tolerability, and pharmacokinetics; establishes maximum tolerated dose

Large comparative RCT (300–3000+ patients) demonstrating efficacy vs standard-of-care; the primary basis for marketing authorisation

Ongoing monitoring of a drug after market approval; detects rare adverse effects, long-term outcomes, and real-world effectiveness data

A physiological state in which abrupt drug discontinuation produces a withdrawal syndrome; a predictable consequence of sustained use, distinct from addiction

Population, Intervention, Comparator, Outcome — a structured framework for formulating clinical questions before searching or evaluating evidence

A pharmacogenomic phenotype where a CYP450 enzyme has minimal or no activity due to two non-functional alleles, causing drug accumulation and toxicity risk

Systematic evaluation of a prescription across five domains: completeness, legibility, rational drug choice, dosing appropriateness, and drug interactions/contraindications

Original research output — RCTs, observational studies, case reports — providing direct but methodologically demanding evidence

The tendency for studies with positive or significant results to be published, while negative studies remain unpublished, skewing the available evidence

A measure of disease burden including quality and quantity of life; 1 QALY = 1 year in perfect health; used in cost-utility analysis to compare drug value across disease areas

An FDC in which both components are clinically indicated simultaneously, the fixed ratio suits most patients, combined use is superior to separate prescribing, and cost is justified

The proportional reduction in event rate between treatment and control; always appears larger than absolute risk reduction and can be misleading without context

Drug category under the Drugs and Cosmetics Act 1940 (India) requiring a physician's prescription for dispensing; covers most prescription medicines

Stricter sub-category for critical antimicrobials; prescription in duplicate; enhanced documentation to curb antimicrobial resistance

Drug category under the Drugs and Cosmetics Act 1940 (India) requiring a specially-formatted prescription with quantity in words; covers psychotropics and narcotics

Databases and systematic reviews that aggregate and index primary literature; e.g. PubMed, Cochrane Library

A correction equation for phenytoin total levels in patients with hypoalbuminaemia: Corrected phenytoin = Measured level ÷ [(0.2 × Albumin g/dL) + 0.1]

The condition in which drug input equals drug elimination, producing stable plasma concentrations; reached after approximately 5 half-lives from initiation or dose change

A measurable proxy (e.g. HbA1c, LDL level) used in trials as a substitute for a clinical outcome (e.g. mortality, MI); reduction in a surrogate does not always translate to clinical benefit

A communication verification technique in which the patient is asked to repeat instructions in their own words; the most evidence-based method to confirm understanding of drug counselling

Synthesised reference works — textbooks, formularies, standard treatment guidelines — most accessible but potentially dated

Measurement of drug concentration in plasma to guide dosing of narrow-therapeutic-index drugs; clinically useful when concentration correlates with efficacy and toxicity

A pharmacological adaptation in which repeated drug exposure reduces drug effect, requiring dose escalation; occurs through receptor down-regulation and compensatory signalling changes

An enzyme that metabolises azathioprine and 6-mercaptopurine; deficiency leads to accumulation of toxic thioguanine nucleotides causing myelosuppression

A zero written after a decimal point in a drug dose (e.g. '5.0 mg') that is a patient-safety hazard — the WHO recommends never writing trailing zeros as they can be misread as '50 mg'

The lowest plasma drug concentration in the dosing interval, measured just before the next dose; the standard TDM sampling time for most drugs

A pharmacogenomic phenotype where excess CYP450 enzyme activity (due to gene duplication) causes rapid drug clearance (therapeutic failure for parent drugs) or rapid prodrug activation (toxicity)

Failure to take medications due to forgetfulness, misunderstanding, or regimen complexity rather than a conscious decision; addressed by simplification and reminder systems

The WHO-validated framework for rational prescribing: define the problem, specify therapeutic objective, select P-drug, write prescription, inform patient, monitor outcome