Basic Pharmacology - Study Guide

**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.*