Nokea
Which doses of Aspirin may be more effective in inhibiting Tromboxane A2?
- A. Low
- B. High
- C. All of the Above
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: Low. Low doses of Aspirin are more effective in inhibiting Thromboxane A2 because they irreversibly inhibit cyclooxygenase-1 in platelets, which is necessary for Thromboxane A2 synthesis. High doses can lead to non-specific inhibition of COX-1 and COX-2, which may cause side effects. Choice B is incorrect because high doses can lead to non-specific inhibition. Choice C is incorrect because high doses are not more effective. Choice D is incorrect as low doses are effective.
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All of the following statements concerning the general principles of therapy with lipid-lowering drugs are true EXCEPT:
- A. Therapy with a lipid-lowering drug should be always accompanied by an appropriate diet
- B. A lipid-lowering diet should be discontinued if it fails to decrease the levels of plasma LDL cholesterol by at least 10%
- C. Lipid-lowering drugs should only be administered after at least 3 months of prior dietary therapy
- D. Some combinations of lipid-lowering drugs are synergistic
Correct Answer: B
Rationale: Answer B is correct because discontinuing a lipid-lowering diet solely based on the immediate reduction in plasma LDL cholesterol levels by 10% is not appropriate. The efficacy of a diet in managing lipid levels should be evaluated over a longer period, considering other factors like overall cardiovascular health and risk factors. Choosing to discontinue the diet based solely on the short-term reduction in LDL cholesterol levels can lead to overlooking other important aspects of cardiovascular health.
Choices A, C, and D are incorrect:
A: This statement is true because combining lipid-lowering drugs with an appropriate diet can enhance the overall effectiveness of therapy in managing lipid levels.
C: This statement is also true as dietary interventions are usually recommended as the first-line approach before resorting to pharmacological therapy.
D: This statement is true as certain combinations of lipid-lowering drugs can indeed work synergistically to achieve better outcomes in managing lipid levels.
Therapeutic dose of digoxin in a normal individual has the following effects, except
- A. Increase in the speed of myocardial contractility
- B. No significant change in cardiac output
- C. Relaxation of peripheral vascular bed
- D. Increase in the force of myocardial contractility
Correct Answer: C
Rationale: Digoxin increases contractility but does not significantly relax peripheral vasculature; it may cause vasoconstriction at toxic levels.
The toxic effects of a large dose of nicotine include all of the following EXCEPT:
- A. Hypotension and bradycardia
- B. Convulsions coma and respiratory arrest
- C. Skeletal muscle depolarization blockade and respiratory paralysis
- D. Hypertension and cardiac arrhythmias
Correct Answer: A
Rationale: The correct answer is A: Hypotension and bradycardia. Nicotine is a stimulant that typically causes hypertension and tachycardia due to its effects on the sympathetic nervous system. Therefore, hypotension and bradycardia are not consistent with the toxic effects of nicotine. Choices B, C, and D are incorrect because convulsions, coma, respiratory arrest, skeletal muscle depolarization blockade, respiratory paralysis, hypertension, and cardiac arrhythmias are all potential toxic effects of a large dose of nicotine due to its impact on various physiological systems.
Mr Khamis, 60 years old, has severe chest pain when he uses the stairs for more than one floor. The pain disappears when he rests. You prescribed the following drug to relieve the chest pain:
- A. Nitroglycerine
- B. Propranolol
- C. Verapamil
- D. Hydralazine
Correct Answer: A
Rationale: Nitroglycerin relieves effort-induced angina by reducing preload.
The principal mechanism of fomepizol action is associated with inhibition of:
- A. Aldehyde dehydrogenase
- B. Acetylcholinesterase
- C. Alcohol dehydrogenase
- D. Monoamine oxidase
Correct Answer: C
Rationale: Certainly! The correct answer is C: Alcohol dehydrogenase. Fomepizole is used in treating methanol and ethylene glycol toxicity by inhibiting alcohol dehydrogenase, preventing the formation of toxic metabolites. This mechanism blocks the conversion of methanol and ethylene glycol into their toxic byproducts, formic acid, and glycolic acid, respectively. Choices A, B, and D are incorrect as fomepizole does not target aldehyde dehydrogenase, acetylcholinesterase, or monoamine oxidase in this context.