MFPEP

-Trifluoromethylphenylpiperazine (TFMPP) is a recreational drug of the phenylpiperazine chemical class and is a substituted piperazine. Usually in combination with benzylpiperazine (BZP) and other analogues, it is sold as an alternative to the illicit drug MDMA (“Ecstasy”).[3][4]

Pharmacology
TFMPP has affinity for the 5-HT1A (Ki = 288 nM), 5-HT1B (Ki = 132 nM), 5-HT1D (Ki = 282 nM), 5-HT2A (Ki = 269 nM), and 5-HT2C (Ki = 62 nM) receptors, and functions as a full agonist at all sites except the 5-HT2A receptor, where it acts as a weak partial agonist or antagonist.[5] Unlike the related piperazine compound meta-chlorophenylpiperazine (mCPP), TFMPP has insignificant affinity for the 5-HT3 receptor (IC50 = 2,373 nM).[6] TFMPP also binds to the SERT (EC50 = 121 nM) and evokes the release of serotonin.[5] It has no effects on dopamine or norepinephrine reuptake or efflux.[5]

Use and effects
TFMPP is rarely used by itself. In fact, TFMPP reduces locomotor activity and produces aversive effects in animals rather than self-administration, which may explain the decision of the DEA not to permanently make TFMPP a controlled substance.[5] More commonly, TFMPP is co-administered with BZP, which acts as a norepinephrine and dopamine releasing agent.[7] Due to the serotonin agonist effects and increase in serotonin, norepinephrine, and dopamine levels produced by the BZP/TFMPP combination, this mixture of drugs produces effects which crudely mimic those of MDMA.[8]

Side effects
The combination of BZP and TFMPP has been associated with a range of side effects, including insomnia, anxiety, nausea and vomiting, headaches and muscle aches which may resemble migraine, seizures, impotence, and rarely psychosis,[4] as well as a prolonged and unpleasant hangover effect. These side effects tend to be significantly worsened when the BZP/TFMPP mix is consumed alongside alcohol, especially the headache, nausea, and hangover.

However, it is difficult to say how many of these side effects are produced by TFMPP itself, as it has rarely been marketed without BZP also being present, and all of the side effects mentioned are also produced by BZP (which has been sold as a single drug). Studies into other related piperazine drugs such as mCPP suggest that certain side effects such as anxiety, headache and nausea are common to all drugs of this class, and pills containing TFMPP are reported by users to produce comparatively more severe hangover effects than those containing only BZP. The drug can also cause the body to tremble for a long period of time.[9][unreliable source?]