) is a prescription medication approved to treat moderate-to-severe pain. It contains a combination of two active ingredients: pentazocine
), a potent pain reliever, and naloxone
), which is added to help deter misuse of Talwin Nx by injection.
Talwin Nx is considered a schedule IV controlled substance
because it has the potential for abuse or addiction. As a controlled substance, the possession and use of the drug are highly regulated. Schedule IV substances are considered to have less abuse potential than schedule II drugs, such as morphine
, or schedule III drugs, such as hydrocodone/APAP
Who Makes This Medication?
Talwin Nx was originally made by sanofi-aventis U.S., LLC. However, sanofi-aventis stopped making the brand-name medication, and it is currently only available in generic form. Generic versions of Talwin Nx are made by a few different companies.
As previously mentioned, Talwin Nx contains pentazocine and naloxone
. Pentazocine is the pain-relieving portion of Talwin Nx. It works by binding to opioid receptors and mimicking the action of naturally occurring chemicals that block pain. Once taken, pentazocine usually starts to relieve pain in 15 to 30 minutes, and can continue to control pain for three hours or longer.
The main effects of pentazocine occur when it binds to receptors in the central nervous system (the brain and spinal cord). However, the drug can produce effects anywhere opioid receptors are found in the body.
There are several types of opioid receptors located throughout the body. Talwin Nx is classified as an opioid agonist-antagonist, which means it binds to and activates certain opioid receptors (kappa receptors), but also blocks certain other opioid receptors (called mu receptors).
As an antagonist at mu opioid receptors, Talwin Nx partially blocks the action of opioid medications that bind to mu receptors, such as morphine. In addition, Talwin Nx is only a partial agonist at kappa receptors, which means it only partially activates them.
Compared to full agonists, such as morphine, partial agonists-antagonists like Talwin Nx usually have a limited effective dosing range. This means there is a maximum dose above which the drug will not have any further effects. This may help make Talwin Nx a less-desirable drug for abuse and make it less dangerous than full agonist drugs, particularly in the case of an overdose; however, an overdose can still be dangerous.
The naloxone portion of Talwin Nx helps prevent the medication from being misused. When taken by mouth as directed, naloxone has no effects in the body. However, if the drug is crushed and injected, naloxone blocks the actions of pentazocine (as well as other narcotic medications), preventing it from working and potentially causing severe withdrawal symptoms.