How do phen-fen diet pills work?
If eating too much is the result of changes in the reward, learning, and habit circuits of the brain, then medicines that act on those circuits really should modify behavior and help manage this impulse of overeating. That is precisely what a mix of two drugs-phentermine and fenfluramine, typically referred to as phen-fen-seemed to do.
Phen-fen turned out to be hazardous and was pulled from the market in 1997. Occasionally, it developed serious and quite often life-threatening unwanted effects in the heart. While no one should use this pharmaceutical mixture today, we can learn a lot about the biology of overindulging by analyzing the way it worked on the brain’s reward circuits. Many physicians say phen-fen was the most efficient drug therapy they ever endured for the treatment of obesity.
Phen-fen acted in a complicated means on two brain chemicals: serotonin and dopamine.
The drug combination improved the amount of serotonin, which shuts down the act of dopamine and decreases activity in the reward pathways. The complete impact was to reduce the drive for reward.
Studies have revealed that serotonin can also tamp down the satisfying value of drugs of abuse, for example cocaine. By way of example, a test animal which has been trained to press a lever to get cocaine will minimize doing so after receiving pharmaceuticals that promote serotonin release. This might be an aid to describe reports in psychopharmacological journals that phentermine and fenfluramine reduce drug use.
If the same pharmacologic therapy reduces the power that both food and drugs of abuse can gain over the body, then they are in all probability engaging the same regions of the brain. Which means the reward circuits targeted by highly palatable food are also the reward circuits targeted by drugs.