Which of the following can be given as a transdermal patch
**Core Concept**
Nitroglycerin is a vasodilator used to manage angina pectoris. Transdermal patches allow for sustained release of the medication, providing a steady reduction in blood pressure and myocardial oxygen demand.
**Why the Correct Answer is Right**
Nitroglycerin is a nitrate ester that undergoes metabolic conversion to nitric oxide (NO), a potent vasodilator. Transdermal patches facilitate the release of nitroglycerin into the bloodstream, where it is converted to NO, leading to smooth muscle relaxation and vasodilation. This results in reduced preload and afterload, decreasing myocardial oxygen demand and alleviating angina symptoms.
**Why Each Wrong Option is Incorrect**
**Option A:** Fentanyl is an opioid analgesic, and while it has a transdermal formulation (e.g., fentanyl patches), it is primarily used for pain management, not angina. **Option B:** Insulin is not administered transdermally; instead, it is given subcutaneously or intravenously. **Option C:** Propranolol is a beta-blocker used to manage hypertension, angina, and tachyarrhythmias, but it is typically administered orally or intravenously, not transdermally.
**Clinical Pearl / High-Yield Fact**
Transdermal patches can provide sustained-release medication, but they may have limitations, such as variable absorption rates and potential skin irritation.
**Correct Answer:** C. Nitroglycerin.