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CNS Pharmacology Important Topics and Questions for MBBS

CNS Pharmacology covers the drugs that act on the brain and spinal cord: sedatives, antiepileptics, antiparkinsonian drugs, antipsychotics, antidepressants, opioids and anaesthetics. It is one of the most heavily examined sections of 2nd Year MBBS Pharmacology. This page lists the important CNS topics, the questions to practise, and Pharmacology question papers from seven universities.

Compiled from university Pharmacology papers. SME-reviewed. Updated 2026.
Open Pharmacology PYQs in the GeckoMed app for offline access and topic-wise revision.

Quick Facts: CNS Pharmacology in MBBS

Detail

MBBS phase

Information

Phase 2 (2nd Year)

Detail

Curriculum

Information

NMC Competency Based Medical Education (CBME)

Detail

Paper placement

Information

Within Pharmacology theory; the paper it appears in depends on your university scheme

Detail

Core areas

Information

Sedative-hypnotics, antiepileptics, antiparkinsonian drugs, antipsychotics, antidepressants, mood stabilisers, opioids, general and local anaesthetics, alcohols

Detail

Question formats

Information

Long essays, short notes, short answers, reasoning questions

Detail

PYQ years on GeckoMed

Information

2025 to 2021 (Tier-1 universities); 2025 to 2023 (other universities)

Papers by University

National pages: MBBS Pharmacology Question Papers | MBBS Pharmacology Important Questions | MGR University Pharmacology Question Papers


CNS Pharmacology Exam Pattern

Question Type

Long essay

What Is Usually Asked

Classification plus detailed account of one prototype drug

How to Structure It

Classification, mechanism of action, pharmacological actions, pharmacokinetics, uses, adverse effects, contraindications, interactions

Question Type

Short note

What Is Usually Asked

One drug or group, such as levodopa or benzodiazepines

How to Structure It

Mechanism, uses, adverse effects, one clinical point

Question Type

Short answer

What Is Usually Asked

Drug of choice, antidote, one adverse effect

How to Structure It

Two to five precise points

Question Type

Reasoning

What Is Usually Asked

"Give reasons" for a combination or a precaution

How to Structure It

Statement, then mechanism

Topic-Wise Priority Table

Priority reflects syllabus weight and standard textbook emphasis for MBBS Pharmacology. It is revision guidance, not a year-by-year frequency count. Paper-wise topic frequency is published in the GeckoMed app as it becomes available.

Topic Area

Sedative-hypnotics

Key Sub-Topics

Benzodiazepines, barbiturates, Z-drugs, flumazenil

Typical Question Style

Long essay or short note

Priority

High

Topic Area

Antiepileptics

Key Sub-Topics

Classification, phenytoin, valproate, carbamazepine, status epilepticus

Typical Question Style

Long essay

Priority

High

Topic Area

Antiparkinsonian drugs

Key Sub-Topics

Levodopa with carbidopa, dopamine agonists, MAO-B inhibitors, anticholinergics

Typical Question Style

Long essay or short note

Priority

High

Topic Area

Antipsychotics

Key Sub-Topics

Typical versus atypical, extrapyramidal effects, clozapine

Typical Question Style

Long essay or short note

Priority

High

Topic Area

Antidepressants

Key Sub-Topics

TCAs, SSRIs, MAO inhibitors, serotonin syndrome

Typical Question Style

Long essay or short note

Priority

High

Topic Area

Mood stabilisers

Key Sub-Topics

Lithium and its toxicity

Typical Question Style

Short note

Priority

High

Topic Area

Opioid analgesics

Key Sub-Topics

Morphine, opioid antagonists, opioid dependence

Typical Question Style

Long essay

Priority

High

Topic Area

General anaesthetics

Key Sub-Topics

Stages of anaesthesia, inhalational and intravenous agents, preanaesthetic medication

Typical Question Style

Long essay or short note

Priority

High

Topic Area

Local anaesthetics

Key Sub-Topics

Mechanism, lignocaine, bupivacaine, adrenaline combination

Typical Question Style

Short note

Priority

High

Topic Area

Alcohols

Key Sub-Topics

Ethanol, disulfiram, methanol poisoning

Typical Question Style

Short note

Priority

Medium

Topic Area

CNS stimulants and others

Key Sub-Topics

Drugs for Alzheimer's disease, drugs for migraine

Typical Question Style

Short note

Priority

Medium

High-Yield Facts to Revise

Topic

Benzodiazepines versus barbiturates

Must-Know Point

Benzodiazepines increase the frequency of GABA-A chloride channel opening; barbiturates increase the duration of opening

Topic

Benzodiazepine antidote

Must-Know Point

Flumazenil

Topic

Phenytoin

Must-Know Point

Shows zero-order kinetics at higher doses; gum hyperplasia and hirsutism are classic adverse effects

Topic

Valproate

Must-Know Point

Broad-spectrum antiepileptic; teratogenic (neural tube defects) and hepatotoxic

Topic

Carbamazepine

Must-Know Point

Enzyme inducer; risk of Stevens-Johnson syndrome, linked to HLA-B*1502 in some Asian populations

Topic

Status epilepticus

Must-Know Point

An intravenous benzodiazepine such as lorazepam is used first

Topic

Levodopa with carbidopa

Must-Know Point

Carbidopa inhibits peripheral dopa decarboxylase, so more levodopa reaches the brain

Topic

Drug-induced parkinsonism

Must-Know Point

Treated with central anticholinergics, not levodopa

Topic

Clozapine

Must-Know Point

Atypical antipsychotic; risk of agranulocytosis requires blood count monitoring

Topic

Neuroleptic malignant syndrome

Must-Know Point

Hyperthermia, rigidity and autonomic instability with antipsychotics; managed with supportive care, dantrolene or bromocriptine

Topic

MAO inhibitors

Must-Know Point

Tyramine-rich foods can cause a hypertensive ("cheese") reaction

Topic

Lithium

Must-Know Point

Narrow therapeutic index; tremor, hypothyroidism and nephrogenic diabetes insipidus

Topic

Morphine

Must-Know Point

Contraindicated in head injury because it raises intracranial pressure and masks signs; antidote naloxone

Topic

Malignant hyperthermia

Must-Know Point

Triggered by volatile anaesthetics and succinylcholine; treated with dantrolene

Topic

Nitrous oxide

Must-Know Point

Can cause diffusion hypoxia at the end of anaesthesia

Topic

Local anaesthetics

Must-Know Point

Block voltage-gated sodium channels; adrenaline prolongs action and reduces systemic toxicity

Topic

Disulfiram

Must-Know Point

Inhibits aldehyde dehydrogenase, producing an unpleasant reaction with alcohol

Topic

Methanol poisoning

Must-Know Point

Fomepizole or ethanol blocks conversion to toxic metabolites

Important CNS Pharmacology Questions to Practise

These questions reflect the style used in MBBS university Pharmacology papers and are not attributed to a specific year or university.

Long Essay Questions

  1. Classify sedative-hypnotics. Describe the mechanism of action, uses and adverse effects of benzodiazepines.
  2. Classify antiepileptic drugs. Describe phenytoin (or sodium valproate) in detail.
  3. Classify drugs used in parkinsonism. Explain why levodopa is combined with carbidopa.
  4. Classify antipsychotic drugs. Describe the adverse effects of chlorpromazine.
  5. Classify antidepressants. Describe the selective serotonin reuptake inhibitors.
  6. Describe the pharmacological actions, uses and adverse effects of morphine.
  7. Classify general anaesthetics. Describe the stages of general anaesthesia.

Short Notes

  1. Flumazenil
  2. Drug treatment of status epilepticus
  3. Lithium
  4. Serotonin syndrome
  5. Neuroleptic malignant syndrome
  6. Atypical antipsychotics
  7. Opioid antagonists
  8. Ketamine
  9. Propofol
  10. Preanaesthetic medication
  11. Lignocaine
  12. Disulfiram
  13. Methanol poisoning
  14. Drugs for Alzheimer's disease

Reasoning Questions

  1. Adrenaline is added to lignocaine for local anaesthesia. It causes vasoconstriction, prolonging the anaesthetic effect and reducing systemic absorption and toxicity.
  2. Morphine is contraindicated in head injury. It depresses respiration, raises intracranial pressure through carbon dioxide retention, and masks the patient's neurological signs.
  3. Levodopa is given with carbidopa. Carbidopa blocks peripheral conversion of levodopa to dopamine, increasing brain delivery and reducing peripheral adverse effects.
  4. Patients on MAO inhibitors must avoid cheese. Tyramine in such foods is not broken down and releases noradrenaline, causing a hypertensive crisis.

How to Prepare for CNS Pharmacology Questions

  • Learn classifications first. Most long essays open with a classification, which carries marks on its own.
  • Master one prototype per group in full detail: diazepam, phenytoin, levodopa, chlorpromazine, imipramine or fluoxetine, and morphine.
  • Make comparison tables, such as typical versus atypical antipsychotics and benzodiazepines versus barbiturates.
  • Memorise antidotes and drugs of choice for quick short answers.
  • Link to physiology, especially neurotransmitters such as GABA, dopamine and serotonin.
  • Use memory aids from Pharmacology Mnemonics.

Frequently Asked Questions

Which CNS pharmacology topics are most important for MBBS?

Benzodiazepines, antiepileptics, antiparkinsonian drugs, antipsychotics, antidepressants, lithium, morphine and general anaesthetics carry most of the long essay weight.

How should I write a long answer on a CNS drug group?

Start with a classification, then describe one prototype drug under mechanism, actions, pharmacokinetics, uses, adverse effects, contraindications and interactions.

Are these CNS pharmacology questions free on GeckoMed?

Yes. The topic lists and university paper links on this page are free to view. The GeckoMed app adds offline access and topic-wise revision.

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