Agents for procedural sedation should be given intravenously, which gives a faster onset and allows for easier titration. The intramuscular route should be reserved for children (Section 7) and those adults with learning difficulties or acute behavioural disturbance (which lies outside of the scope of the learning session). It is worth emphasizing the need to use smaller initial doses in the elderly and to allow the drug extra time to take effect, given the slower arm-brain circulation time in such patients. In contrast, those patients with regular alcohol consumption that comfortably exceed current recommendations may require larger sedative doses than usual to achieve the required level of sedation. Titration is not necessarily straightforward, the therapeutic window being narrow in these cases. All the drugs listed have the capacity to produce deeper levels of sedation and even anaesthesia if used in excess. Further, combinations of drugs, especially sedatives and opioids, should be employed with caution. The opioids should be given first to allow time to become maximally effective before any sedative is added. The dissociative drug ketamine offers a unique sedative state that will be considered in detail in the section on sedation for children.
You should be familiar with two reversal agents, naloxone and flumazenil. Use of reversal agents should not be considered a routine the requirement of a reversal agent to be administered should trigger a local review of the case.3
Naloxone can be titrated 100 200mcg every 1 2 minutes to reverse respiratory depression following opioid administration. Its effects may wear off before the opioid is cleared so you should consider extended patient monitoring. Naloxone may precipitate withdrawal in opioid dependent patients, and it will also antagonise any opioid analgesia.
Give flumazenil in small increments of 100 200mcg every minute to reverse respiratory depression following benzodiazepine use. Use it with caution in those on long term benzodiazepines, or who have consumed other drugs (prescribed or recreational) as there is the potential to precipitate seizures.
It is worth noting that reversal agents may have a shorter halflife than the drugs they are being used to reverse, so patients who require a reversal agent should be monitored for an extended period.