N2O Anxiolysis and Analgesia — MFDS Part 1 MCQ

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ModeratePharmacologyN2O Anxiolysis and AnalgesiaMFDS Part 1

An anxious adult is planned for dental treatment under conscious sedation, with local anaesthesia used for operative pain control. Which pharmacological agent also produces an intrinsic mild analgesic effect in addition to anxiolysis?

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Correct answer: E — Nitrous oxide in oxygen

Nitrous oxide in oxygen is correct. At concentrations used for inhalation conscious sedation, nitrous oxide reduces anxiety and has an intrinsic mild analgesic effect, including elevation of the pain threshold. This analgesia is limited and does not replace effective local anaesthesia for painful dental procedures. Midazolam and diazepam are benzodiazepines that provide anxiolysis, sedation and amnesia but no intrinsic analgesia. Propofol produces hypnosis and sedation without analgesia. Sevoflurane is principally a volatile general anaesthetic and is not the standard single-agent conscious-sedation technique for routine UK dental care. SDCEP identifies titrated nitrous oxide/oxygen as the standard UK inhalation-sedation technique.

Reference: Khinda V, Rao D, Singh Sodhi SP. Nitrous Oxide Inhalation Sedation Rapid Analgesia in Dentistry: An Overview of Technique, Objectives, Indications, Advantages, Monitoring, and Safety Profile. International Journal of Clinical Pediatric Dentistry. 2023;16(1):131–138. https://www.sdcep.org.uk/published-guidance/conscious-sedation/