[New opioids for general anaesthesia and in- and out-hospital analgesia]

Over the last 30 years, three new opioids of the piperidine family have been introduced to anaesthesia clinical practice: sufentanil, alfentanil and remifentanil. Alfentanil is a derivative of fentanyl, with quicker onset than that of fentanyl and with shorter duration and more intense vagomimetic properties than those of fentanyl and sufentanil. It may cause less intense respiratory depression than equianalgesic doses of fentanyl. Clinical trials indicate that alfentanil can be used effectively as an analgesic, as an analgesic supplement to anaesthesia, and as the major component of a general anaesthetic. Its short duration of effect makes it attractive as an analgesic supplement for short ambulatory surgical procedures. Sufentanil is a more potent and more lipophilic analgesic than fentanyl. It would appear to maintain haemodynamic stability during surgery better than other opioids. Epidural sufentanil produces a rapid onset and good quality of analgesia. In addition, low doses administered intravenously via a PCA pump seem to have a potential role for analgesia during labour. Remifentanil is an opioid analgesic that is rapidly metabolized by non-specific blood and tissue esterases. According to its unique pharmacokinetic profile, remifentanil-based anaesthesia combines high-dosage opioid analgesia intraoperatively with a rapid and predictable postoperative awakening, even after long procedures. Its vagomimetic properties are especially pronounced in small children, the elderly and hypovolaemic patients, and in these groups atropine should be always given before remifentanil administration. Remifentanil also minimises the adrenergic response to endotracheal intubation. Three mju agonist-antagonists have been used for pain treatment: nalbuphine, butorphanol and buprenorphine. They can be used in ambulatory settings. Nalbuphine can be used parenterally. It reverses morphine-induced respiratory depression while maintaining adequate analgesic effect. Buprenorphine can be given sublingually, percutanenously, epidurally and parenterally. It is a potent analgesic, recommended for strong postoperative pain. Butorphanol is a potent analgesic that increases heart rate, arterial and pulmonary blood pressures and cardiac output. It should be given carefully in patients with coronary disease.