Narcotic agonist-antagonists

Administration of a narcotic agonist-antagonist may result in symptoms of narcotic witiidrawal in those addicted to narcotics. Other adverse reactions associated widi die administration of a narcotic agonist-antagonist... 

When monitoring a patient receiving a narcotic agonist-antagonist, the nurse must be aware that... 

The narcotic agonist/antagonist nalbuphine (8.88) is poorly bioavailable in humans (ca. 10%), mostly due to extensive first-pass metabolism. Two prodrugs were examined, namely the acetylsalicylate (8.89) and the anthran-ilate (8.90) [125]. The hydrolysis of these compounds in rat plasma was fast (tU2 values of some minutes and 1 - 2 h, respectively), while it was slow in dog plasma (lW2 ca. 3 h and 15 h, respectively) and in human plasma (t1/2 ca. 7-10 h and 50-60 h, respectively). Hydrolysis in dog tissue homogenates was also markedly slower than in rat. The dog was, thus, considered to be a fair animal model, and it is of interest that, in this species, the oral bioavailability of 8.88, 8.89, and 8.90 were ca. 6, 20, and 50%, respectively. 

Mechanism of Action A narcotic agonist-antagonist that binds with opioid receptors in the CNS. May displace opioid agonists and competitively inhibit their action may precipitate withdrawal symptoms. Therapeutic Effect Alters the perception of and emotional response to pain. 

Note. For a review of the pharmacokinetics of narcotic agonists-antagonists, see R. E. S. Bullingham etal., Clin. Pharmacokinet., 1983,, 332-343. 

Xylazine (0.5 mg/kg i.v.) alone had minimal effects on gastroduodenal motility, but when combined with the narcotic agonist-antagonist butorphanol there is pronounced suppression of antroduode-nal myoelectric activity (Merritt et al 1998). Interestingly, butorphanol alone had minimal effects on antroduodenal myoelectric activity. However, detomidine, at 0.0125 mg/kg, markedly depressed duodenal motility and would be expected to affect gastric motility similarly. 

Narcotic agonist-antagonists are medications that have both agonist and antagonist effects on the opioid receptors. 

What are the advantages of prescribing narcotic agonist-antagonists ... 

Narcotic agonist-antagonists are less potent and have a lower dependency potential than opioids. Withdrawal symptoms from narcotic agonist-antagonists are not as severe as with narcotic agonists (narcotic analgesics). 

Iorio MA, Frigni V (1984) Narcotic agonist/antagonist properties of quaternary diastereo-isomers derived from oxymorphone and naloxone. Eur J Med Chem 19 301-303... 

Nalbuphine, a narcotic agonist-antagonist (10 mg in adult administered SC, IM, or IV every 3 to 6 hours) is indicated for the relief of moderate to severe pain, for preoperative analgesia, as a supplement to balanced analgesia and to surgical anesthesia, and for obstetrical analgesia during labor and delivery. 

See Narcotic Agonist-Antagonists listed in the Appendix. Detailed tables show doses, recommendations, expectations, side effects, contraindications, and more available on the book s Web site (see URL in Appendix). 

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