NALBUPHINE HYDROCHLORIDE

Originator

Nubain,Du Pont,US,1979

The Uses of NALBUPHINE HYDROCHLORIDE

Nalbuphine is the free base form of Nalbuphine Hydrochloride. Nalbuphine is a mixed opioid agonist-antagonist. Nalbuphine is an analgesic (narcotic).

The Uses of NALBUPHINE HYDROCHLORIDE

Analgesic;Opioid ligand

Manufacturing Process

To a slurry of 110.5 g of 14-hydroxydihydronormorphinone in 2.5 liters of methylene chloride and 280 ml of triethylamine was added a solution of 106 g of cyclobutanecarboxylic acid chloride in 500 ml of methylene chloride. The temperature of the reaction mixture was maintained at 20°C to 25°C during the addition. After 5 minutes the reaction mixture was brought to reflux and heated for 5 hours.
It was then cooled, washed with water, dried over sodium sulfate and evaporated to dryness. The residue was crystallized from benzene and pentane to give 138.5 g of the dicyclobutanecarbonyl derivative, melting point about 112°C (dec.).
The dicyclobutanecarbonyl derivative (136.7 g) was dissolved in 200 ml of tetrahydrofuran and added dropwise to a suspension of 34.2 g of lithium aluminum hydride in 1 liters of tetrahydrofuran. The temperature of the mixture rose to reflux during the addition. Reflux was maintained for 2 hours after the addition was completed. After cooling, 110 ml of ethyl acetate was added dropwise, followed by 30 ml of water, followed by a solution of 53 g of ammonium chloride in 125 ml of water. The resulting mixture was filtered and the inorganic precipitate was washed with methanol. Evaporation of the combined filtrates gave 66 g of N-cyclobutylmethyl-14-hydroxydihydronormorphinone, melting point 229°C to 231°C.

brand name

Nubain (Endo).

Therapeutic Function

Analgesic

Acquired resistance

Nalbuphine is an antagonist at μ receptors and an agonist at κ receptors. As an antagonist, it has approximately one-fourth the potency of naloxone, and it produces withdrawal when given to addicts. On a weight basis, the analgesic potency of nalbuphine approaches that of morphine. An intramuscular injection of 10 mg will give about the same degree and duration of analgesia as an equivalent dose of morphine.

Clinical Use

Nalbuphine is only available for parenteral dosage. Its elimination half-life is 2 to 3 hours. Metabolism of nalbuphine is by conjugation of the 3-OH group, and greater than 90% of the drug is excreted as conjugates in the feces.

Side Effects

Side effects of nalbuphine are like those of other κ. Dysphoria is not as common as with pentazocine. Sedation is the most common side effect. Nalbuphine does not have the adverse cardiovascular properties found with pentazocine and butorphanol. Nalbuphine has low abuse potential and is not listed under the Controlled Substances Act.