Ans. C: Propofol Benzodiazepines, e.g. diazepam, lorazepam and midazolam, are widely used as sedative agents in the ICU. Diazepam use has become less common as newer shoer-acting benzodiazepines have become available. Lorazepam is more potent than midazolam and, because of its low lipid solubility, crosses the blood-brain barrier more slowly, delaying its onset of action and prolonging the sedative effect. Hence, it is recommended for longer-term sedation while midazolam is preferred for sho-term sedation Propofol, another frequently used sedative agent, resembles midazolam in terms of pharmacological profile. Midazolam and propofol have similar efficacy and safety in sedating various groups of critically ill patients. Midazolam is, however, cheaper than propofol Neveheless, propofol, when used as a sedative in mechanically ventilated patients, is associated with shoer weaning times and hence, while midazolam may be cheaper, the overall cost-benefit analysis taking into account duration of mechanical ventilation and ICU stay may in fact be better with propofol.