Shortest acting Benzodiazepine –
**Core Concept**
Benzodiazepines are a class of psychoactive drugs that exert their effects through the enhancement of the activity at the GABA_A receptor, leading to sedative, hypnotic, anxiolytic, anticonvulsant, and muscle relaxant properties. The duration of action of benzodiazepines varies among different agents, depending on their pharmacokinetic properties such as half-life.
**Why the Correct Answer is Right**
The shortest-acting benzodiazepine is Triazolam, which has a half-life of approximately 1.5-5.5 hours. This is due to its rapid onset of action, high lipid solubility, and extensive first-pass metabolism. Triazolam's pharmacokinetic profile allows for a rapid increase in its plasma concentration, followed by a rapid decrease, making it the shortest-acting benzodiazepine.
**Why Each Wrong Option is Incorrect**
**Option A:** Midazolam is a short-acting benzodiazepine, but its half-life is longer than Triazolam's, ranging from 1.5 to 2.5 hours.
**Option B:** Lorazepam is an intermediate-acting benzodiazepine with a half-life of 10-20 hours, which is significantly longer than Triazolam's.
**Option C:** Diazepam is a long-acting benzodiazepine with a half-life of 20-70 hours, making it one of the longest-acting agents in this class.
**Clinical Pearl / High-Yield Fact**
When choosing a benzodiazepine, it's essential to consider the duration of action, as this can impact the risk of next-day sedation, dependence, and withdrawal symptoms.
**Correct Answer: D. Triazolam.**