KAPS Pharmacology and Therapeutics 1 — Questions and Answers
Question 1: Which receptor type does acetylcholine primarily act on in the parasympathetic nervous system?
- Alpha-adrenergic
- Beta-adrenergic
- Muscarinic (Correct answer)
- Nicotinic
Correct answer: Muscarinic
Acetylcholine is the primary neurotransmitter of the parasympathetic nervous system. In this system, it primarily acts on muscarinic receptors, which are G-protein coupled receptors found on target organs like the heart, smooth muscle, and glands. Activation of these receptors mediates the 'rest and digest' responses characteristic of parasympathetic activity.
Question 2: What is the primary mechanism of action of beta-blockers in treating hypertension?
- Increasing cardiac output
- Reducing heart rate and cardiac output (Correct answer)
- Dilating peripheral arteries
- Inhibiting angiotensin II production
Correct answer: Reducing heart rate and cardiac output
Beta-blockers primarily treat hypertension by blocking beta-adrenergic receptors, particularly beta-1 receptors in the heart. This blockade leads to a decrease in heart rate and myocardial contractility, which in turn reduces the heart's overall workload and cardiac output. Consequently, the blood pressure is lowered, making them effective antihypertensive agents.
Question 3: Which class of drugs is most effective in managing acute asthma attacks?
- Inhaled corticosteroids
- Short-acting beta-agonists (Correct answer)
- Leukotriene receptor antagonists
- Long-acting beta-agonists
Correct answer: Short-acting beta-agonists
Short-acting beta-agonists (SABAs), such as albuterol, are the most effective class of drugs for managing acute asthma attacks. They work by rapidly relaxing the smooth muscles in the airways, leading to bronchodilation and immediate relief of symptoms like wheezing and shortness of breath. Their quick onset of action makes them crucial 'rescue' medications for acute exacerbations.
Question 4: What is the main adverse effect of aminoglycosides?
- Hepatotoxicity
- Nephrotoxicity and ototoxicity (Correct answer)
- Bone marrow suppression
- Hypoglycemia
Correct answer: Nephrotoxicity and ototoxicity
Aminoglycosides are a class of antibiotics known for their significant adverse effects on the kidneys (nephrotoxicity) and inner ear (ototoxicity). These drugs accumulate in renal tubular cells and the hair cells of the cochlea and vestibular system, leading to cellular damage and impaired function. Close monitoring of renal function and hearing is essential during aminoglycoside therapy to mitigate these risks.
Question 5: Which anticoagulant works by directly inhibiting thrombin?
- Warfarin
- Dabigatran (Correct answer)
- Heparin
- Aspirin
Correct answer: Dabigatran
Dabigatran is a direct thrombin inhibitor (DTI) that works by directly binding to and inhibiting both free and clot-bound thrombin. Thrombin is a crucial enzyme in the coagulation cascade, responsible for converting fibrinogen to fibrin, which forms the structural mesh of a blood clot. By inhibiting thrombin, dabigatran effectively prevents the formation of new clots and the extension of existing ones.
Question 6: What is the therapeutic use of selective serotonin reuptake inhibitors (SSRIs)?
- Treating hypertension
- Treating depression (Correct answer)
- Relieving acute pain
- Managing diabetes
Correct answer: Treating depression
Selective serotonin reuptake inhibitors (SSRIs) are a class of antidepressants primarily used for treating depression and various anxiety disorders. Their mechanism of action involves blocking the reuptake of serotonin into the presynaptic neuron, which increases the concentration of serotonin in the synaptic cleft. This enhanced serotonergic neurotransmission helps to alleviate depressive symptoms.
KAPS Pharmacology and Therapeutics 1
Which receptor type does acetylcholine primarily act on in the parasympathetic nervous system?