Nokea
This drug is an inhibitor of renin synthesis:
- A. Propranolol
- B. Enalapril
- C. Diazoxide
- D. Losartan
Correct Answer: A
Rationale: The correct answer is A: Propranolol. Propranolol is a beta-blocker that inhibits renin synthesis by blocking beta-1 adrenergic receptors in the juxtaglomerular cells of the kidney. This leads to decreased renin release and ultimately reduces the production of angiotensin II. Enalapril (B) is an ACE inhibitor that acts downstream by inhibiting the conversion of angiotensin I to angiotensin II. Diazoxide (C) is a potassium channel activator and Losartan (D) is an angiotensin II receptor blocker, both of which do not directly inhibit renin synthesis.
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Route of administration of vitamin D3 is:
- A. Subcutaneous
- B. Oral
- C. Intravenous
- D. Intranasal
Correct Answer: B
Rationale: The correct route of administration for vitamin D3 is oral (Choice B) because it is a fat-soluble vitamin that can be effectively absorbed through the digestive system. Subcutaneous (Choice A) and intravenous (Choice C) routes are not typically used for vitamin D3 as it can lead to potential risks and complications. Intranasal (Choice D) administration is not a common route for vitamin D3 absorption, as it may not provide adequate bioavailability compared to oral ingestion. Therefore, the oral route is the most appropriate and efficient method for administering vitamin D3.
A 46-year-old man underwent surgery to remove a glioma of the left brain lobe. An intravenous infusion of a drug was started to induce controlled hypotension to minimize blood loss during surgery. Which of the following drugs would be most appropriate for this purpose?
- A. Labetalol
- B. Hydralazine
- C. Nifedipine
- D. Nitroprusside
Correct Answer: D
Rationale: The correct answer is D: Nitroprusside. Nitroprusside is a potent vasodilator that can rapidly induce controlled hypotension by relaxing smooth muscle in blood vessels. This helps in minimizing blood loss during surgery. Labetalol (A) is a non-selective beta-blocker with alpha-blocking activity, which may not provide rapid hypotension. Hydralazine (B) is a direct vasodilator that can cause reflex tachycardia and may not be as effective in controlled hypotension. Nifedipine (C) is a calcium channel blocker primarily used for hypertension but does not provide rapid hypotension like nitroprusside.
Compared with epinephrine, norepinephrine produces all of the following effects EXCEPT:
- A. Similar effects on beta1 receptors in the heart and similar potency at an alfa receptor
- B. Decrease the mean pressure below normal before returning to the control value
- C. Significant tissue necrosis if injected subcutaneously
- D. Increase both diastolic and systolic blood pressure
Correct Answer: B
Rationale: Step 1: Norepinephrine is a neurotransmitter that acts on both alpha and beta receptors.
Step 2: Norepinephrine has more potent effects on alpha receptors compared to epinephrine.
Step 3: Choice A is correct as norepinephrine has similar effects on beta1 receptors in the heart and similar potency at alpha receptors.
Step 4: Choice C is incorrect as tissue necrosis is associated with dopamine, not norepinephrine.
Step 5: Choice D is incorrect as norepinephrine increases both diastolic and systolic blood pressure.
Step 6: Choice B is correct as norepinephrine does not decrease mean pressure below normal before returning to the control value, making it the exception among the effects listed.
The client has developed neutropenia from a medication. What medication might this be?
- A. Metoprolol
- B. Captopril
- C. Lisinopril
- D. Guanfecine
Correct Answer: B
Rationale: Captopril, an ACE inhibitor, is associated with rare neutropenia, unlike the other listed drugs.
The mechanism of valproate action is:
- A. Facilitation glutamic acid decarboxylase, the enzyme responsible for GABA synthesis and inhibition of GABA-aminotransferase, the enzyme responsible for the breakdown of GABA (enhance GABA accumulation)
- B. Inhibition of voltage sensitive Na+ channels
- C. Inhibition of low threshold (T-type) Ca2+ channels
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D: All of the above. Valproate's mechanism of action involves multiple pathways.
1. Valproate facilitates GABA synthesis by inhibiting GABA breakdown enzyme and enhancing GABA accumulation.
2. It inhibits voltage-sensitive Na+ channels, reducing neuronal excitability.
3. It also inhibits low threshold (T-type) Ca2+ channels, further reducing neuronal excitability.
These combined actions lead to increased GABAergic transmission and decreased excitatory neurotransmission, contributing to its antiepileptic and mood stabilizing effects. Other choices are incorrect because they do not encompass all the mechanisms involved in valproate's action.