.png | CAS_number = 132875-61-7 | ATC_prefix = N01 | ATC_suffix = AH06 | ATC_supplemental = | PubChem = 60815 | DrugBank = APRD01216 | chemical_formula = C₂₀H₂₈N₂O₅ | molecular_weight = 376.447 g/mol | smiles = | melting_point = 5 | bioavailability = | protein_bound = 70% (bound to plasma proteins) | metabolism = | elimination_half-life = 1-20 minutes | pregnancy_category = | legal_status = | routes_of_administration = }} Remifentanil is a potent ultra short-acting synthetic opioid analgesic drug. It is given to patients during surgery to relieve pain and as an adjunct to an anaesthetic. Remifentanil is used for sedation as well as combined with other medications for use in general anesthesia.

Dosing

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It is administered in the form remifentanil hydrochloride and in adults is given as an intravenous infusion in doses ranging from 0.1 microgram per kilogram per minute to 0.5 (µg/kg)/min. Children may require higher infusion rates (up to 1.0 (µg/kg)/min). Doses listed in the package insert from its manufacturer are much higher than those used in actual clinical practice. The clinically useful infusion rates are 0.025-0.1 (µg/kg)/min for sedation (rates adjusted to age of patient, severity of their illness and invasiveness of surgical procedure). Small amounts of other sedative medication are given along with the remifentanil to produce sedation. Clinically useful infusion rates in general anesthesia are similar to those used for sedation, except other potent medications are utilized along with the Remifentanil in the case of general anesthesia.

Metabolism

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Unlike other synthetic opioids, its clearance is dependent on non-specific plasma esterases. This means that accumulation does not occur with remifentanil and its context-sensitive half-life remains at 4 minutes after a 4 hour infusion.

Remifentanil is metabolised to a compound (remifentanil acid) which has 1/1600 the potency of the parent compound.

Side-effects

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Remifentanil is a specific μ-receptor agonist. Hence, it causes a reduction in sympathetic nervous system tone, respiratory depression and analgesia. The drug's effects include a dose-dependent decrease in heart rate and arterial pressure and respiratory rate and tidal volume. Muscle rigidity is sometimes noted.

The most common side effects reported by patients receiving this medication are a sense of extreme "dizzines" (often short lived, a common side effect of other fast acting synthetic piperidine narcotics such as fentanyl and alfentanil) and intense pruitis (or "itching"), often around the face. These side effects are often controlled by either altering the dose of administration (decreasing or in some cases, increasing the dose) or by administering other sedatives that allow the patient to tolerate or lose awareness of the side effect.

Nausea can occur as a side effect of remifentanil, however, it is quite transient in nature (usually) due to the drug's short half life which rapidly removes it from the patient's circulation once the infusion is terminated.

References

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Opioids | Piperidines

Remifentanil | รีมิเฟนทานิล