Remifentanil
Overview
Remifentanil is a synthetic opioid analgesic developed in the 1990s, classified as a 4-anilidopiperidine derivative. It was designed to address the need for an opioid with predictable pharmacokinetics during anesthesia. Unlike other opioids, its ester structure allows rapid metabolism by nonspecific blood and tissue esterases, independent of liver or kidney function. As a μ-opioid receptor agonist, it provides analgesia and sedation comparable to fentanyl but with a uniquely short duration of action (5-10 minutes). This makes it particularly valuable in surgical settings where rapid titration and quick recovery are required, such as cardiac surgery or outpatient procedures.
Physical and Chemical Properties
Remifentanil hydrochloride is typically supplied as a lyophilized powder or solution. The compound is structurally characterized by a piperidine ring with an ester linkage, which is key to its rapid hydrolysis. It has pKa values of 7.07 (tertiary nitrogen) and 8.52 (phenolic OH), with logP (octanol-water partition coefficient) of 1.75 indicating moderate lipid solubility. The drug maintains stability in aqueous solutions at pH 2-5 but degrades rapidly at alkaline pH. Its degradation products include remifentanil acid (GI90291), which has negligible pharmacological activity. These properties necessitate careful handling during pharmaceutical preparation and administration.
Main Applications
In clinical practice, remifentanil is primarily administered via continuous IV infusion (0.05-2 mcg/kg/min) due to its extremely short context-sensitive half-time (3-5 minutes regardless of infusion duration). It is frequently used in balanced anesthesia combined with propofol or volatile anesthetics, allowing precise control of intraoperative analgesia with rapid postoperative recovery. Specialized applications include neurosurgery (where rapid emergence facilitates neurological assessment), obstetric analgesia (minimal neonatal depression), and pediatric anesthesia. Its predictable offset makes it unsuitable for postoperative pain management unless combined with longer-acting analgesics before discontinuation.
Safety and Storage
As a Schedule II controlled substance, remifentanil requires strict inventory control and secure storage. Unopened vials should be kept in original packaging at room temperature; reconstituted solutions are stable for 24 hours at room temperature or 4 days refrigerated. The drug must be protected from light to prevent degradation. Critical safety considerations include mandatory respiratory monitoring and immediate access to naloxone. The rapid offset can lead to acute pain if alternative analgesia isn't established. Contraindications include opioid-naïve patients without mechanical ventilation and those with hypersensitivity to fentanyl analogs. Institutional protocols should govern its use to mitigate diversion risks.
B2B Procurement Guide
Pharmaceutical purchasers must verify licensure compliance (DEA Form-222 in the US) and maintain auditable transaction records. Bulk procurement is typically limited to hospitals and accredited surgical centers. Leading manufacturers include Mylan (owner of the Ultiva brand) and various generic producers like Hikma Pharmaceuticals. When evaluating suppliers, confirm GMP certification and stability testing documentation. Given the drug's potency, ensure supply chain integrity to prevent counterfeit products. Many institutions implement just-in-time ordering due to the controlled substance requirements and the drug's high unit cost compared to other opioids.