Master essential pharmacology concepts. Our study guide covers drug actions, mechanisms, and key terms for Year 3 students.
Course Code: DBS 3103 / MBPL3611 Institution: --- SECTION A: MULTIPLE CHOICE QUESTIONS (MCQs) GENERAL PHARMACOLOGY Question 1 Pharmacodynamics includes the study of: A. Mechanisms of drug action B. Biotransformation of drugs in the organism C. Distribution of drugs in the organism D. Excretion of drugs in the organism E. All of the above Answer: A Explanation: Pharmacodynamics specifically studies the mechanisms of drug action and the biochemical and physiological effects of drugs on the body. Options B, C, and D describe pharmacokinetic processes (what the body does to the drug), while pharmacodynamics describes what the drug does to the body. --- Question 2 Which of the following physiological changes in the elderly may lead to the need to reduce the dose of a prescribed medication? A. Increased rate of drug absorption B. Increased rate of hepatic drug biotransformation C. Decreased efficiency in drug biotransformation D. Decreased total body fluid as a proportion of body mass E. None of the above Answer: C Explanation: Elderly patients experience decreased hepatic enzyme activity and reduced liver blood flow, leading to decreased drug biotransformation. This results in prolonged drug half-life and increased drug accumulation, necessitating dose reduction to prevent toxicity. --- Question 3 What does the term "affinity" mean? A. A measure of how tightly a drug binds to plasma proteins B. A measure of how tightly a drug binds to a receptor C. A measure of the inhibitory potency of a drug D. A measure of the bioavailability of a drug Answer: B Explanation: Affinity refers to the strength of the interaction between a drug and its receptor. High affinity means the drug binds strongly to the receptor, requiring lower concentrations to achieve binding. This is distinct from efficacy, which describes the ability to produce an effect once bound. --- Question 4 A pharmacological antagonist is a drug that: A. Binds to the receptor and initiates changes in cell function, producing a suboptimal effect B. Binds to the receptor and initiates changes in cell function, producing an optimal effect C. Interacts with plasma proteins but does not produce any effect D. Binds to the receptors without directly altering their function Answer: D Explanation: An antagonist binds to a receptor but does not activate it. Instead, it blocks the receptor site, preventing endogenous ligands or agonists from binding and producing their effects. Antagonists have affinity but no intrinsic activity (efficacy). --- Question 5 Irreversible inhibition is due to: A. Ionic bond B. Covalent bond C. Hydrogen bond D. All of the above Answer: B Explanation: Irreversible inhibition occurs through covalent bond formation between the drug and its target. Covalent bonds are very strong and permanent, making the inhibition essentially irreversible. The effect only diminishes when new enzymes or receptors are synthesized. --- Question 6 Which of the following parameters is used to indicate the ability of a drug to produce the desired effect? A. Potency B. Intrinsic activity C. Therapeutic index D. Efficacy Answer: D Explanation: Efficacy refers to the maximum response a drug can produce, regardless of dose. It indicates the drug's ability to produce the desired therapeutic effect. Potency refers to the dose required to produce a given effect, while efficacy describes the magnitude of that effect. --- Question 7 Drug receptors are found on: A. Plasma membranes only B. Plasma membranes and plasma proteins C. Plasma proteins only D. Plasma membranes and intracellular structures Answer: D Explanation: Drug receptors are located on plasma membranes (G-protein coupled receptors, ion channels, enzyme-linked receptors) and intracellularly (nuclear receptors for steroid hormones, thyroid hormones). This allows drugs to interact with various cellular components to produce therapeutic effects. --- AUTONOMIC NERVOUS SYSTEM Question 8 Nicotinic receptor sites do not include which of the following? A. Bronchial smooth muscle B. Adrenal medullary cells C. Parasympathetic ganglia D. Skeletal muscle end plates E. Sympathetic ganglia Answer: A Explanation: Bronchial smooth muscle contains muscarinic receptors (M3), not nicotinic receptors. Nicotinic receptors are found at neuromuscular junctions (skeletal muscle), autonomic ganglia (both sympathetic and parasympathetic), and adrenal medulla. --- Question 9 Which of the following is the neurotransmitter agent normally released in the sinoatrial node (SAN) of the heart in response to an increase in blood pressure? A. Acetylcholine B. Dopamine C. Epinephrine D. Glutamine E. Norepinephrine Answer: A Explanation: When blood pressure increases, baroreceptors activate parasympathetic (vagal) output to the heart. The vagus nerve releases acetylcholine at the SA node, which binds to M2 muscarinic receptors, causing bradycardia and reduced cardiac output to lower blood pressure. --- Question 10 Which of the following drugs facilitates catecholamine transmitter release from adrenergic nerve endings? A. Dopamine B. Epinephrine C. Amphetamine D. Norepinephrine E. Reserpine Answer: C Explanation: Amphetamine is an indirect sympathomimetic that enters adrenergic nerve terminals and displaces stored norepinephrine, causing its release into the synaptic cleft. This mechanism is responsible for amphetamine's stimulant effects. Reserpine, in contrast, depletes catecholamine stores. --- Question 11 Full activation of the sympathetic nervous system, as in the fight-or-flight reaction, may occur during maximal exercise. Which of the following effects is most likely to occur? A. Bronchoconstriction B. Increased intestinal motility C. Decreased renal blood flow D. Miosis E. Bradycardia Answer: C Explanation: During sympathetic activation, blood is redirected from non-essential organs (including kidneys and GI tract) to skeletal muscles, heart, and brain. This causes decreased renal blood flow. Other sympathetic effects include bronchodilation, decreased GI motility, mydriasis (pupil dilation), and tachycardia. --- Question 12 Mr. Otieno has been diagnosed with myasthenia gravis. You are considering treatment with pyridostigmine and neostigmine. Which adverse effect is associated with these two drugs? A. Bronchoconstriction B. Irreversible action C. Constipation D. Diarrhea E. Reduced gastric secretions Answer: D Explanation: Pyridostigmine and neostigmine are acetylcholinesterase inhibitors that increase acetylcholine levels at all cholinergic sites, including the GI tract. This leads to increased GI motility and secretions, causing diarrhea. Other cholinergic effects include bronchoconstriction, increased secretions, and bradycardia. --- Question 13 Probable signs of atropine overdose in toddlers include which one of the following? A. Gastrointestinal smooth muscle cramping B. Tachycardia C. Increased gastric secretion D. Pupillary constriction Answer: B Explanation: Atropine is an antimuscarinic that blocks parasympathetic effects. Overdose presents with "hot as a hare, blind as a bat, dry as a bone, red as a beet, mad as a hatter." Tachycardia results from blockade of vagal (M2) receptors in the heart. Other signs include mydriasis, decreased secretions, and hyperthermia. --- Question 14 Which of the following is the most dangerous effect of belladonna alkaloids in infants and toddlers? A. Dehydration B. Hallucinations C. Hyperthermia D. Hypertension E. Intraventricular heart block Answer: C Explanation: Hyperthermia is the most life-threatening effect in children because belladonna alkaloids (atropine) block sweat glands, preventing heat dissipation. Children have less efficient thermoregulation and higher metabolic rates, making them particularly vulnerable to dangerous temperature elevations. --- Question 15 Which is the treatment of choice in a child with signs of anaphylaxis after being stung by three bees? A. Diphenhydramine B. Ephedrine C. Epinephrine D. Dexamethasone E. Isopro