All Free Pharmacology MCQs with Answers

• A. Staining of teeth
• B. Aplastic anaemia
• C. Bone marrow suppression
• D. B & C

Explanation: Chloramphenicol inhibits mitochondrial protein synthesis in haemopoietic cells, causing dose-related bone-marrow suppression and, rarely…

• A. More reliable oral obsorption
• B. Greater resistance to pencillinase
• C. Slower renal excretion
• D. Broader antibacterial spectrum

Explanation: Penicillin V is more acid-stable than penicillin G, so it survives gastric acid and gives more reliable absorption after oral…

• A. Chloramphenicol
• B. Gentamicin
• C. Sulphadiazine
• D. Tetracycline

Explanation: Gentamicin is primarily bactericidal because it irreversibly disrupts bacterial protein synthesis and causes misreading of mRNA.

• A. Anaphylactic shock
• B. Diarrhoea
• C. Oral candidiasis
• D. Renal failure

Explanation: Diarrhoea is the commonest adverse effect of oral ampicillin, caused by disturbance of normal intestinal flora and direct gastrointestinal…

• A. Labetalol
• B. Clonidine
• C. Enalapril
• D. Nifedipine

Explanation: Clonidine stimulates central α₂ receptors, reducing sympathetic outflow from vasomotor centres and thereby lowering blood pressure.

• A. It is produces more acetylcholine
• B. It inhibits the action of cholinesterase
• C. It produces more acetycholine receptors
• D. It increases the action of cholinesterase

Explanation: Neostigmine reversibly inhibits acetylcholinesterase, so acetylcholine remains longer at the neuromuscular junction and improves muscle…

• A. CNS stimulation
• B. Muscle fasciculation
• C. CNS depression
• D. Decreased salivation

Explanation: Succinylcholine is a depolarising neuromuscular blocker, so persistent end-plate depolarisation first produces visible muscle…

• A. Ach is transmitter at both pre & post synaptic junction
• B. It causes dilatation of skeletal muscles
• C. Post ganglionic fibres are longer than pre ganglionic fibres
• D. Noradrenalin is the neurotransmitter at post ganglionic junction

Explanation: All parasympathetic preganglionic and postganglionic neurons release acetylcholine, acting at nicotinic ganglia and muscarinic effector…

• A. Promethazine
• B. Diphenhydramine
• C. Hydroxyzine
• D. Loratidine

Explanation: Loratadine is a second-generation H1 antihistamine with poor penetration into the central nervous system, so it causes much less sedation.

• A. Common cold
• B. Systemic anaphylaxis
• C. Motion sickness
• D. Parkinsonism

Explanation: H1 antihistamines are useful in colds, as an adjunct in anaphylaxis, and for motion sickness because of their antihistaminic and often…

• A. Diphenydramine
• B. Promethazine
• C. Terfenadine
• D. Pyrilamine

Explanation: Terfenadine is a second-generation H1 blocker with minimal penetration into the brain and negligible antimuscarinic activity.

• A. Ephederine
• B. Atropine
• C. Propranolone
• D. Morphine

Explanation: Atropine blocks muscarinic receptors and reduces salivation, but its anticholinergic action can raise intraocular pressure, making it…

• A. Cough
• B. Headache
• C. Drowsiness
• D. Vertigo

Explanation: Many antihistamines, especially first-generation H1 blockers, cross the blood-brain barrier and commonly cause drowsiness.

• A. Amitriptyline
• B. Disopyrmide
• C. Atenolol
• D. Neostigmine

Explanation: Neostigmine inhibits acetylcholinesterase, increasing acetylcholine at muscarinic sites and therefore increasing salivary secretion rather…

• A. Causes arteriolar dialation
• B. causes bronchodialtion
• C. Causes pain when injected subcutaneously
• D. Is released following injury and in certain allergic responses

Explanation: Histamine causes arteriolar vasodilation, produces pain when injected intradermally or subcutaneously, and is released in injury and…

• A. Lorazepam
• B. Pirenzepine
• C. Ranitidine
• D. Chlorpheniramine

Explanation: Drug-allergic skin manifestations such as itching and urticaria are treated with an H1 antihistamine such as chlorpheniramine.

• A. Atropine
• B. Neostigmine
• C. Physostigmine
• D. Scopolamine

Explanation: Neostigmine is a permanently charged quaternary ammonium compound, so it does not significantly cross the blood-brain barrier.

• A. Epinephrine
• B. Hydrocortisone
• C. Succinylcholine
• D. All of the above

Explanation: Epinephrine is the immediate drug of choice in anaphylaxis because it rapidly reverses bronchospasm, vasodilation and urticaria through…

• A. Atropine
• B. Chlorpheniramine
• C. Imipramine
• D. Neostigmine

Explanation: Atropine, chlorpheniramine and imipramine reduce salivation through antimuscarinic effects and therefore cause dry mouth.

• A. Asthma
• B. Myocardial infarction
• C. Shock
• D. Anaphylaxis

Explanation: Adrenaline is useful in anaphylaxis, some shock states and severe bronchospasm, but it increases myocardial oxygen demand and can worsen…