Description of the medicine: Pentazocin (Pentazocinum)
PENTAZOCINE (Pentazocinum). (#) 2-hydroxy-5, 9-dimethyl-2- (3, 3-dimethylallyl) -6, 7-benzomorphan.
Synonyms: Lexir, Fortral, Dolapent, Fortal, Fortalgesic, Fortral, Fortralin, Lexir, Magadolin, Pentagin, Pentazocine, Sosegon, Sosenyl, Sosigon, Talwin, etc.
Pentazocine is a synthetic compound containing the benzomorphan core of a morphine molecule, but lacking the oxygen bridge and the third six-membered core, characteristic of compounds of the morphine group.
The nitrogen in the piperidine core is substituted with dimethylallyl [CH 2 - CH = C (CH 3) 2]
The preparation was obtained according to the principle of modifying a morphine molecule, taking into account that some previously synthesized compounds that are close to morphine but do not contain an oxygen bridge (levorphanol, or lemoran, etc.) have a high analgesic activity; at the same time the dimethylallyl residue is an important part of the nalorphine molecule (see), which possesses to a large extent the properties of a morphine antagonist. It was assumed that such a modification of the morphine molecule will lead to a compound with greater analgesic activity than nalorphine, but with less side effects than morphine. Pentazocine to some extent satisfies these requirements. It has analgesic activity, although to a lesser extent than morphine, but it depresses breathing less, less often causes constipation and urinary retention. At present, antagonist agonists more active than pentazocine (nalbuphine and others) have been obtained.
Pentazocine is well absorbed by ingestion and parenteral administration. The peak concentration in blood plasma is observed after 15 minutes - 1 hour after intramuscular injection and after 1 - 3 hours after ingestion. The half-life is 2 to 3 hours.
Indications are basically the same as for morphine.
In acute pain, the drug is administered parenterally, with chronic pain inward.
The dose for adults under the skin, intramuscularly or intravenously, is usually 0.03 g (30 mg), and for severe pain - 0.045 g (45 mg). Intravenously administered slowly. If necessary, repeat the introduction under the skin or intramuscularly after 3-4 hours, intravenously - after 2 to 3 hours.
Inside appoint adults 0.05 g (50 mg = 1 tablet) 3-4 times a day (before meals). With severe pain, a single dose is sometimes increased to 0.1 g.
The daily dose for adults should not exceed 350 mg when taken orally.
Children aged 1 year to 6 years are prescribed the drug parenterally: intramuscularly and subcutaneously - at the rate of not more than 1 mg per 1 kg of body weight per day, intravenously - not more than 0.5 mg / kg per day. Children aged 6 to 12 years are prescribed by mouth 0.225 g (25 mg = 1/2 tablet) every 3-4 hours.
Pentazocine is generally well tolerated. However, nausea, vomiting, dizziness, increased sweating, redness of the skin, and respiratory depression are possible. Sometimes there may be euphoria, confusion, urinary retention.
With a sudden cessation of administration after prolonged use of the drug in relatively large doses, withdrawal symptoms (abdominal cramps, nausea, vomiting, agitation, trembling, etc.) are possible.