A patient with Graves’ disease exhibits symptoms of tachycardia, heat intolerance, and exophthalmos. Which drug is used to alter thyroid hormone levels prior to surgery?

Choice A rationale:

Increasing the amiodarone infusion rate would worsen the patient's bradycardia and hypotension. Amiodarone is a class III antiarrhythmic drug that works by prolonging the action potential duration in cardiac cells. This can lead to a decrease in heart rate and contractility.

Increasing the dose in this patient could lead to further hemodynamic compromise.

Choice B rationale:

Decreasing the amiodarone infusion rate is the most appropriate action in this situation. This will help to mitigate the drug's effects on the patient's heart rate and blood pressure.

A dose reduction may allow the heart rate to recover to a safer level while still maintaining the antiarrhythmic benefits of amiodarone.

Choice C rationale:

Continuing the amiodarone infusion at the current rate is not appropriate, as it is likely to worsen the patient's bradycardia and hypotension.

Maintaining the current dose could lead to further clinical deterioration.

Choice D rationale:

Discontinuing the amiodarone infusion entirely may not be necessary at this point. The patient's arrhythmia may still require treatment with amiodarone.

A dose reduction may be sufficient to address the patient's hemodynamic instability while still providing therapeutic benefits.

Choice A rationale:

Oxytocin is a hormone that stimulates uterine contractions. It is not a tocolytic, which is a medication that inhibits uterine contractions. In fact, oxytocin is often used to induce labor or to augment labor that is progressing slowly.

It acts on the myofibrils in the uterine muscle, causing them to contract more forcefully and frequently. This leads to cervical dilation and effacement, and ultimately to the birth of the baby.

Oxytocin is typically administered as an intravenous (IV) infusion. The dosage is carefully titrated to achieve the desired effect on the uterus.

It is important to note that oxytocin can have serious side effects, including uterine hyperstimulation, fetal distress, and postpartum hemorrhage. Therefore, it should only be used under the close supervision of a healthcare provider.

Choice B rationale:

Magnesium sulfate is a tocolytic that is often used to prevent preterm labor. It works by relaxing the smooth muscle of the uterus.

It is typically administered as an IV infusion. The dosage is carefully monitored to ensure that the magnesium level in the blood does not become too high.

Side effects of magnesium sulfate can include flushing, nausea, vomiting, and headache. In rare cases, it can also cause serious complications such as respiratory depression and cardiac arrest.

Choice C rationale:

Nifedipine is a calcium channel blocker that is sometimes used as a tocolytic. It works by relaxing the smooth muscle of the uterus and blood vessels.

It is typically administered as an oral tablet. Side effects of nifedipine can include headache, dizziness, flushing, and low blood pressure.

Choice D rationale:

Indomethacin is a nonsteroidal anti-inflammatory drug (NSAID) that is sometimes used as a tocolytic. It works by inhibiting the production of prostaglandins, which are substances that promote uterine contractions.

It is typically administered as an oral tablet or suppository. Side effects of indomethacin can include nausea, vomiting, heartburn, and diarrhea.