**8. Medications used in GI endoscopy**

There is still no perfect medication available for PSA and the combinations of two or more group of agents such as benzodiazepines, opioids, intravenous anesthetics inhalational anesthetics and topical anesthesia is commonly used (**Table 5**). Drug combinations works synergistically which reduces the doses of sedative agents and its side effects. Combination of opioid and sedation is most commonly used regimen. Sedative agents should be titrated to effect in divided doses and the amount of incremental doses should not exceed the maximum recommended doses. In the absence of a weight-related dosage (i.e., mg/kg) for drug doses, the dose for a 'normal' patient weighing 70 kg must be considered to be the dose.

Some anesthesiologist societies advise that general anesthetic inductors (propofol, ketamine, etomidate, dexmedetomidine) and short-acting opioids (fentanyl, alfentanil, sufentanil, remifentanil) should be used only by physicians who have


*ICP, intracranial pressure; IOP, intraocular pressure; IV, intravenous.*

*Moderate sedation (conscious sedation): purposeful response to verbal commands and intact airway and cardiopulmonary functions; deep sedation: response to painful stimulation and requirement of assistance for proper ventilation and airway patency.*

**Table 5.**

*Summary of sedation drugs commonly used.*

been specifically trained in anesthesia or intensive care medicine, or by experienced sedation professionals who have at least advanced life support certification and specialized in unique advanced sedation procedures with anesthetic expertise.

Benzodiazepines (e.g. midazolam, diazepam, flunitrazepam, lorazepam or temazepam) and dexmedetomidine are included as procedural sedative drugs. Midazolam is the most widely employed benzodiazepine [18].

Pharyngeal aerosol spray of local anesthetics such as lidocaine, benzocaine may be considered to suppress gag reflex, decrease the dose of sedatives, and facilitate insertion of endoscope. Their effect may last up to an hour.

Benzocaine may cause methemoglobinemia and should be avoided in patients with a previous history of methemoglobinemia or known glucose-6-phosphate dehydrogenase deficiency.
