Pentazocine

Clinical data

Pregnancy
category

AU: C
US: C (Risk not ruled out) or D (if used near to term)

Routes of
administration

Oral, IV, IM

ATC code

N02AD01 (WHO)

Legal status

AU: S8 (Controlled)
CA: Schedule I
DE: Anlage III (Prescription only)
US: Schedule IV
Schedule III (international)

Pharmacokinetic data

~20% orally

15 min

2 to 3 hours

Identifiers

(2RS,6RS,11RS)-6,11-dimethyl-3-(3-methylbut-2-en-1-yl)-1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocin-8-ol
or
2-dimethylallyl-5,9-dimethyl-2'-hydroxybenzomorphan

CAS Number

359-83-1^Y

PubChem (CID)

DB00652^Y

390041^Y

RP4A60D26L^Y

D00498^Y

CHEMBL560^Y

Chemical and physical data

Formula

C₁₉H₂₇NO

Molar mass

285.424 g/mol

3D model (Jmol)

Interactive image

SMILES

Oc1ccc3c(c1)[C@]2([C@H]([C@H](N(CC2)C\C=C(/C)C)C3)C)C

InChI

InChI=1S/C19H27NO/c1-13(2)7-9-20-10-8-19(4)14(3)18(20)11-15-5-6-16(21)12-17(15)19/h5-7,12,14,18,21H,8-11H2,1-4H3/t14-,18+,19+/m0/s1^Y
Key:VOKSWYLNZZRQPF-GDIGMMSISA-N^Y

Pentazocine is a synthetically-prepared prototypical mixed agonist–antagonist narcotic (opioid analgesic) drug of the benzomorphan class of opioids used to treat moderate to moderately severe pain. Pentazocine is sold under several brand names, such as Fortral, Sosegon, Talwin NX (with the μ-antagonist naloxone, will cause withdrawal in opioid dependent persons on injection), Talwin, Talwin PX (without naloxone), Fortwin (Lactate injectable form) and Talacen (with acetaminophen). This compound may exist as one of two enantiomers, named (+)-pentazocine and (−)-pentazocine. (−)-pentazocine is a κ-opioid receptor agonist, while (+)-pentazocine is not, instead displaying a ten-fold greater affinity for the σ receptor. Usually, in its oral formulations, it is combined with naloxone so as to prevent people from crushing the tablets, dissolving them in a solvent (like water) and injecting them for a high (as naloxone is not orally bioavailable it produces no effect when the formulation is used orally, but it blocks the opioid effects of pentazocine if injected intravenously for a high). Related drugs include phenazocine, dezocine, cyclazocine and several chemicals used in research on the central nervous system.

Pentazocine is used primarily to treat pain, although its analgesic effects are subject to a ceiling effect. It has been discontinued by its corporate sponsor in Australia, although it may be available through the special access scheme.

In the 1970s, recreational drug users discovered that combining pentazocine with tripelennamine (a first-generation ethylenediamine antihistamine most commonly dispensed under the brand names Pelamine and Pyribenzamine) produced a euphoric sensation. Since tripelennamine tablets are typically blue in color and brand-name Pentazocine is known as Talwin (hence "Ts"), the pentazocine/tripelennamine combination acquired the slang name Ts and blues. After health-care professionals and drug-enforcement officials became aware of this scenario, the mu-opioid-antagonist naloxone was added to oral preparations containing pentazocine to prevent injection misuse, and the reported incidence of its misuse has declined precipitously since.

...
Wikipedia