Tick the drug, blocking acetylcholine transmission at the myoneural junction of helminthes:

Correct Answer: A

Rationale: The correct answer is A: Levamisole. Levamisole blocks acetylcholine transmission at the myoneural junction of helminthes by inhibiting cholinesterase enzyme. This leads to paralysis and expulsion of the parasites from the host. Mebendazole (B) works by inhibiting microtubule synthesis in helminthes. Piperazine (C) causes paralysis by hyperpolarizing the helminth's muscle cells. Niclosamide (D) disrupts the helminth's energy metabolism. Therefore, Levamisole is the correct choice for blocking acetylcholine transmission specifically.

Correct Answer: B

Rationale: The correct answer is B: Adenosine. Adenosine is commonly used for treating supraventricular tachycardias, which can cause palpitations. It works by slowing electrical conduction in the heart, helping to restore normal heart rhythm. Mexiletine (A) is a sodium channel blocker used for ventricular arrhythmias. Sotalol (C) is a beta-blocker used for atrial and ventricular arrhythmias. Verapamil (D) is a calcium channel blocker used for atrial arrhythmias but not typically for palpitations due to supraventricular tachycardias.

Correct Answer: F

Rationale: The correct answer is B: Mexiletine. After administering amiodarone for atrial fibrillation and wide QRS, the next drug should target the wide QRS complex, indicating possible ventricular involvement. Mexiletine, a Class IB antiarrhythmic, is commonly used to treat ventricular arrhythmias. Lidocaine (A) is also a Class IB antiarrhythmic, but Mexiletine is preferred in this scenario due to its longer half-life. Phenytoin (C) is not indicated for atrial fibrillation or wide QRS. Nifedipine (D) is a calcium channel blocker and is not appropriate for treating ventricular arrhythmias.

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.