Pharmacology
Bachelor of Medicine & Bachelor of Surgery (MBChB) • Year 1 • Semester 1, 2026
General, Autonomic & Autacoid Pharmacology (PHA 121) | Chemotherapy of Infections & Malignancies (PHA 222)
Instructions to Candidates
- Answer ALL questions in Section A (Objectives & Fill-ins).
- Answer any THREE questions from Section B.
- Answer any TWO questions from Section C.
- Write clearly and legibly. Generic drug names are preferred over brand names.
- Do not write anything in the margins.
Section A
40 MARKSPart I — Objectives (20 Marks). Answer ALL questions. Choose the most appropriate answer.
1. The time required for the plasma concentration of a drug to fall by 50% is known as:
2. A drug that binds to a receptor and produces a submaximal response even at full occupancy is called a:
3. Atropine exerts its effect by acting as a:
4. Which receptor subtype mediates bronchodilation when stimulated by salbutamol?
5. Which autacoid is responsible for the classic triple response (redness, wheal, flare) in skin injury?
6. Penicillins exert their bactericidal effect primarily by:
7. Which class of antibiotics is classically associated with tendon rupture and QT prolongation as adverse effects?
8. Amphotericin B exerts its antifungal action by:
9. The drug of choice for uncomplicated Plasmodium falciparum malaria in most endemic African settings is:
10. Methotrexate exerts its anticancer effect by inhibiting:
11. Which second messenger is generated when noradrenaline acts on α1-adrenoceptors?
12. Organophosphate poisoning is treated with atropine and which other agent?
13. Which route of administration avoids first-pass hepatic metabolism?
14. Aspirin's antiplatelet effect is due to irreversible inhibition of:
15. Which anti-tuberculosis drug is most associated with peripheral neuropathy, prevented by co-administration of pyridoxine (Vitamin B6)?
16. Metronidazole is particularly effective against which class of organisms?
17. Acyclovir selectively targets virus-infected cells because it requires activation by:
18. Vincristine, a vinca alkaloid, exerts its anticancer effect by:
19. The "cheese reaction" (hypertensive crisis with tyramine-containing foods) is a classic risk with which drug class?
20. Albendazole and mebendazole act against helminths primarily by:
Part II — Fill in the Blanks (20 Marks). Answer ALL questions in this part.
Section B
30 MARKSAnswer any THREE questions from this section.
- Describe the four phases of pharmacokinetics (ADME) and briefly explain one clinically relevant factor that can alter each phase.
- Compare and contrast the actions of the sympathetic and parasympathetic nervous systems on the heart, eye, and gastrointestinal tract.
- Discuss the mechanism of action, two clinical uses, and two adverse effects of histamine H1 receptor antagonists.
- Outline the mechanism of resistance development in bacteria and give three examples of resistance mechanisms with a relevant drug class for each.
- Describe the mechanism of action, spectrum of activity, and two major adverse effects of aminoglycosides (e.g. gentamicin).
Section C
30 MARKSAnswer any TWO questions from this section.
- Discuss the classification of anticancer drugs by mechanism of action (alkylating agents, antimetabolites, mitotic inhibitors, antibiotics, hormonal agents), giving one example and one major adverse effect for each class.
- Describe the pharmacological management of uncomplicated and severe (complicated) Plasmodium falciparum malaria, including drug choice, mechanism of action, and key adverse effects.
- Discuss the pharmacotherapy of Human Immunodeficiency Virus (HIV) infection. Describe the major classes of antiretroviral drugs, their mechanisms of action, and the rationale for combination (HAART) therapy.
