What is the action of ergotamine?

Choice A rationale

Class I antiarrhythmic drugs block sodium channels, affecting phase 0 of the action potential, not phase 3.

Choice B rationale

Class IV antiarrhythmic drugs block calcium channels, which affects phase 2 of the action potential and slows heart rate and conduction.

Choice C rationale

Class III antiarrhythmic drugs block potassium channels, prolonging phase 3 of the action potential. This results in a prolonged repolarization period, reducing the risk of arrhythmia.

Choice D rationale

Class II antiarrhythmic drugs are beta-blockers that primarily affect phase 4 of the action potential, reducing heart rate and conduction, but they do not block potassium channels.

Choice A rationale

It is not correct to say that women are more prone to adverse effects from medications than men. Adverse effects can vary based on individual responses, and gender is not the sole determinant.

Choice B rationale

Women of reproductive age are often excluded from early-phase drug trials due to the potential risks that experimental drugs could pose to developing fetuses. The reproductive risk needs to be carefully managed to avoid harm.

Choice C rationale

While it is true that drugs can affect women differently than men, this answer does not directly address the specific reason why women are excluded from Phase 1 studies, which is primarily due to the potential risks to reproductive health.

Choice D rationale

This is incorrect because drugs are not tested only on men because they are stronger. This statement is not scientifically accurate and does not reflect the principles of clinical trial design.