Nalbuphine Morphine

Nalbuphine hydrochloride is structurally related to oxymorphone and naloxone. It is approximately equipotent with morphine. Nalbuphine is metabolised in the liver to inactive metabolites. The plasma terminal half-life is approximately 5 h. The onset of analgesia is within 2-3 min of intravenous administration and 15 min after intramuscular injection, and lasts 3-6 h with an adult dose of 10 mg. With equi-analgesic doses, similar degrees of respiratory depression to that of morphine occur up to a dose of approximately 0.45 mg-kg-1. With higher doses a ceiling effect occurs. Sedation, possibly mediated by K-receptor activation, occasionally occurs. The incidence of psychotomimetic side effects is lower than with pentazocine. The abuse potential is low, but is can cause withdrawal symptoms in opioid-dependent subjects. It has occasionally been used to reverse opioid-induced respiratory depression. 

Nalbuphine was approximately equianalgesic with morphine (1) and its hemodynamic and respiratory effects were not statistically significantly different from those of morphine (SEDA-14, 69). Other studies have shown that this also apphes to other organ systems. However, unlike morphine, nalbuphine has a ceiling effect on respiratory depression, a low incidence of dysphoric effects, and a low addiction potential. Ten patients with a history of cardiac or orthopedic problems who received intravenous nalbuphine (6-20 mg) required additional doses of morphine (15-70 mg) to relieve pain (2). However, this report was not supported by objective physiological measures or recognized pain scores. 

Proteins Opiate receptors Morphine, nalbuphin, nalaxone... 

Wilson, T.D. Recent advances in HPLC analysis of analgesics. J.Liq.Chromatogr., 1986, 9, 2309-2410 [also antipyrine, aspirin, buprenorphine, butorphanol, codeine, cyclazocine, diamorphine, dihydrocodeine, etorphine, fentanyl, heroin, hydrocodone, hydromorphone, ibuprofen, LAAM, levorphanol, meperidine, methadone, morphine, nalbuphine, naproxen, oxycodone, ox nnorphone, pentazocine, phenacetin, phenazocine, phenylbutazone, propoxyphene, salicylamide, salicylic acid, zomepirac]... 

Simultaneous buprenorphine, butorphanol, ethylmorphine, fentanyl, meperidine, morphine, nalbuphine, nalorphine, tramadol... 

Nalbuphine The combination of morphine + nalbuphine reduced the incidence of morphine-induced pruritus [126 ]. Patients undergoing gynecological operations were randomly allocated to five groups, each of which received varying ratios of the combination regimen ... 

The quest for compounds that combined the analgesic properties of morphine, were nonaddictive, and lacked the side effects of nalorphine, led to the development of the dmgs shown in Table 3. These compounds have both agonist and antagonist activities. Nalbuphine (14) (23) and buprenorphine... 

The drugs naltrexone and nalbuphine are semi-synthetic analogues of the analgesic morphine. Morphine is a good painkiller, but has some unpleasant side effects, the most serious of which is the likelihood of becoming addicted. 

Patients dependent on narcotics Patients dependent on narcotics may experience withdrawal symptoms upon the administration of nalbuphine. If unduly troublesome, control by slow IV administration of small increments of morphine until relief occurs. If the previous analgesic was morphine, meperidine, codeine or another narcotic... 

Pharmacology Nalbuphine is a potent analgesic with narcotic agonist and antagonist actions. Its analgesic potency is essentially equivalent to that of morphine on a milligram basis. 

Respiratory depression At the usual adult dose of 10 mg/70 kg, nalbuphine causes respiratory depression approximately equal to that produced by equal doses of morphine. However, nalbuphine exhibits a ceiling effect increases in dosage beyond 30 mg produce no further respiratory depression. Respiratory depression induced by nalbuphine can be reversed by naloxone. Administer nalbuphine with caution at low doses to patients with impaired respiration (eg, from other medication, uremia, bronchial asthma, severe infection, cyanosis, or respiratory obstructions). 

The most known narcotics are the opium alkaloids such as morphine, codeine, thebaine, papaverine, noscapine and their derivatives and modified compounds such as nalmorphine, apomorphine, apomopholcodine, dihydrocodeine, hydro-morphone and heroine, also known as diamorphine. Synthetic narcotics share the structural skeleton of morphine and include dextromethorphan, pentazocine, phenazocine meperidine (pethidine), phentanyl, anfentaitil, remifentalin, methadone, dextropropoxyphene, levoproxyphene, dipipanone, dextromoramide, meptazinol and tramadol. Thebaine derivatives are also modified narcotics and include oxycodone, oxymorphone, etorphine, buprenorphine, nalbuphine, naloxone or naltrexone. Narcotics can be semi-synthesized or totally synthesized from the morphine and thebaine model. The compounds serve various purposes in clinical practise. 

Nalbuphine is a strong -receptor agonist and a -receptor antagonist it is given parenterally. At higher doses there seems to be a definite ceiling—not noted with morphine—to the respiratory depressant effect. Unfortunately, when respiratory depression does occur, it may be relatively resistant to naloxone reversal. 

Chen, J.C., Smith, E.R., Cahill, M., Cohen, R., Fishman, J.B. The opioid receptor binding of dezocine, morphine, fentanyl, butorphanol and nalbuphine. Life Sci. 1993, 52, 389-396. 

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