USMLE MCQ 36-40 : Which of the following medications have the highest risk of producing this arrythmia

Question: 36
Which of the following medications have the highest risk of producing this arrythmia when the patient is also taking amiodarone?
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a) Flecainide
b) Phenytoin
c) Propafenone
d) Chloroquine
e) Lidocaine

Question: 37
A 55yr old presented with sharp pain on the left side of the face. It was associated with flinching on the face precipitated by eating. The patient was diagnosed to be suffering from trigeminal neuralgia.
The drug of choice for the treatment of trigeminal neuralgia is
a) Indomethacin
b) Sodium valproate
c) Carbamazepine
d) Phenobarbitone
e) Colchicine

Question: 40
An elderly woman with type 2 diabetes has poorly controlled blood glucose levels despite treatment with metformin. The physician decides to try pioglitazone.
Which best describes the mode of action of pioglitazone?
a) reduces insulin resistance and improves insulin sensitivity
b) suppresses basal hepatic glucose production
c) reduces fasting plasma glucose
d) activates the AMP-activated protein kinase
e) stimulates first-phase insulin secretion in the pancreatic beta cells

Question: 36

Correct Answer: E
Explanation:
Common clinical features in drug-induced torsade de pointes include hypokalemia and cycle-length prolongation just prior to initiation of the arrhythmia
Among these agents sotalol, which is a class III agent, has the highest risk of producing torsades, which is a polymorphic, pause-dependent ventricular tachycardia causing syncope and sudden cardiac death.

Question: 37

Correct Answer: C
Explanation:
Trigeminal neuralgia is a disorder characterized by severe pain along the second and third divisions of the trigeminal nerve. The severe pain causes the patient to flinch on the face and the pain is usually precipitated by eating. The etiology of the pain is not exactly known but the current hypothesis suggests that the pain is due to the compression of the nerve rootlets at their entry to the brain stem by aberrant loops of the cerebellar arteries.
Carbamazepine is basically an anti-epileptic drug but it is the drug of choice used for the treatment of Trigeminal neuralgia. The drug is highly effective in reducing the pain. Exact mechanism for the antineuralgic action is unknown; may involve gamma-aminobutyric acid (GABAB) receptors, which may be linked to calcium channels.
Indomethacin is a very potent non-steroidal anti-inflammatory drug but it is of no use in trigeminal neuralgia.
Phenobarbitone & sodium valproate are also anti-epileptic drugs but they are not useful in the treatment of trigeminal neuralgia.
Colchicine is the drug used for pain relief in gouty arthritis and has no role in trigeminal neuralgia.

Question: 40

Correct Answer: A
Explanation:
An elevated rate of basal hepatic glucose output is the primary determinant of elevated fasting blood glucose levels in patients with type 2 diabetes. The primary effect of metformin is the suppression of basal hepatic glucose production, thereby reducing fasting plasma glucose . Metformin does not stimulate insulin secretion; in contrast, metformin reduces fasting plasma insulin and improves whole-body insulin-stimulated glucose metabolism (insulin sensitivity). While it is possible that the beneficial effect of metformin on insulin sensitivity is mediated directly, a more likely explanation is that it is secondary to a reduction in hyperglycemia, triglycerides, and free fatty acids. Recent in vitro and in vivo evidence has shown that metformin activates the AMP-activated protein kinase


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