# Meta-Chlorophenylpiperazine

meta-Chlorophenylpiperazine (mCPP) is a psychoactive drug of the phenylpiperazine class. It was initially developed in the late-1970s and used in scientific research before being sold as a designer drug in the mid-2000s. It has been detected in pills touted as legal alternatives to illicit stimulants in New Zealand and pills sold as "ecstasy" in Europe and the United States.
Despite its advertisement as a recreational substance, mCPP is actually generally considered to be an unpleasant experience and is not desired by drug users. It lacks any reinforcing effects, but has "psychostimulant, anxiety-provoking, and hallucinogenic effects." It is also known to produce dysphoric, depressive, and anxiogenic effects in rodents and humans, and can induce panic attacks in individuals susceptible to them. It also worsens obsessive–compulsive symptoms in people with the disorder.
mCPP is known to induce headaches in humans and has been used for testing potential antimigraine medications. It has potent anorectic effects and has encouraged the development of selective 5-HT$_{2C}$ receptor agonists for the treatment of obesity as well.

## Pharmacology
### Pharmacodynamics

meta-Chlorophenylpiperazine :
| Site | K$_i$ (nM) | Species | Refs |
| SERTTooltip Serotonin transporter | 202–432 | Human | |
| NETTooltip Norepinephrine transporter | 1,940–4,360 | Human | |
| DATTooltip Dopamine transporter | ND | ND | ND |
| 5-HT$_{1A}$ | 44–400 | Human | |
| 5-HT$_{1B}$ | 89–501 | Human | |
| 5-HT$_{1D}$ | 210–1,300 | Human | |
| 5-HT$_{1E}$ | ND | ND | ND |
| 5-HT$_{1F}$ | ND | ND | ND |
| 5-HT$_{2A}$ | 32–398 | Human | |
| 5-HT$_{2B}$ | 3.2–63 | Human | |
| 5-HT$_{2C}$ | 3.4–251 | Human | |
| 5-HT$_3$ | 427 | Human | |
| 5-HT$_4$ | ND | ND | ND |
| 5-HT$_{5A}$ | 1,354 | Human | |
| 5-HT$_6$ | 1,748 | Human | |
| 5-HT$_7$ | 163 | Human | |
| α$_1$ | 97–2,900 | Human | |
| α$_{1A}$ | 1,386 | Human | |
| α$_{1B}$ | 915 | Human | |
| α$_{1D}$ | ND | ND | ND |
| α$_2$ | 112–570 | Human | |
| α$_{2A}$ | 145 | Human | |
| α$_{2B}$ | 106 | Human | |
| α$_{2C}$ | 124 | Human | |
| β | 2,500 | Human | |
| β$_1$ | 2,359 | Human | |
| β$_2$ | 3,474 | Human | |
| D$_1$ | 7,000 | Human | |
| D$_2$ | >10,000 | Human | |
| D$_3$ | >10,000 | Rat | |
| D$_4$ | ND | ND | ND |
| D$_5$ | >10,000 | Human | |
| H$_1$ | 326 | Human | |
| mAChRs | >10,000 | Human | |
| nAChRsTooltip Nicotinic acetylcholine receptors | >10,000 | Human | |
| σ$_1$ | ND | ND | ND |
| σ$_2$ | 8,350 | Rat | |
| I$_1$ | 759 | Rat | |
| VDCCTooltip Voltage-dependent calcium channel | 6,043 | Rat | |
| Values are K$_i$ (nM). The smaller the value, the more strongly the drug binds to the site. ||||
mCPP possesses significant affinity for the 5-HT$_{1A}$, 5-HT$_{1B}$, 5-HT$_{1D}$, 5-HT$_{2A}$, 5-HT$_{2B}$, 5-HT$_{2C}$, 5-HT$_3$, and 5-HT$_7$ receptors, as well as the SERT. It also has some affinity for α$_1$-adrenergic, α$_2$-adrenergic, H$_1$, I$_1$, and NET. It behaves as an agonist at most serotonin receptors. mCPP has been shown to act not only as a serotonin reuptake inhibitor but as a serotonin releasing agent as well.
mCPP's strongest actions are at the 5-HT$_{2B}$ and 5-HT$_{2C}$ receptors and its discriminative cue is mediated primarily by 5-HT$_{2C}$. Its negative effects such as anxiety, headaches, and appetite loss are likely mediated by its actions on the 5-HT$_{2C}$ receptor. Other effects of mCPP include nausea, hypoactivity, and penile erection, the latter two the result of increased 5-HT$_{2C}$ activity and the former likely via 5-HT$_3$ stimulation.
In comparison studies, mCPP has approximately 10-fold selectivity for the human 5-HT$_{2C}$ receptor over the human 5-HT$_{2A}$ and 5-HT$_{2B}$ receptors (K$_i$ = 3.4 nM vs. 32.1 and 28.8 nM). It acts as a partial agonist of the human 5-HT$_{2A}$ and 5-HT$_{2C}$ receptors but as an antagonist of the human 5-HT$_{2B}$ receptors.
Despite acting as a serotonin 5-HT$_{2A}$ receptor agonist, mCPP has been described as non-hallucinogenic. However, hallucinations have occasionally been reported when large doses of mCPP are taken.

### Pharmacokinetics

mCPP is metabolized via the CYP2D6 isoenzyme by hydroxylation to para-hydroxy-mCPP (p-OH-mCPP) and this plays a major role in its metabolism. The elimination half-life of mCPP is 4 to 14 hours.
mCPP is a metabolite of a variety of other piperazine drugs including trazodone, nefazodone, etoperidone, mepiprazole, cloperidone, peraclopone, and BRL-15,572. It is formed by dealkylation via CYP3A4. Caution should be exercised in concomitant administration of CYP2D6 inhibitors such as bupropion, fluoxetine, paroxetine, and thioridazine with drugs that produce mCPP as a metabolite as these drugs are known to increase concentrations of the parent molecule (e.g., trazodone) and of mCPP.

## Chemistry
### Analogues

Analogues of mCPP include:
* 1-Benzylpiperazine (BZP)
* 1-Methyl-4-benzylpiperazine (MBZP)
* 1,4-Dibenzylpiperazine (DBZP)
* 3-Trifluoromethylphenylpiperazine (TFMPP)
* 3,4-Methylenedioxy-1-benzylpiperazine (MDBZP)
* 4-Bromo-2,5-dimethoxy-1-benzylpiperazine (2C-B-BZP)
* 4-Fluorophenylpiperazine (pFPP)
* 4-Methoxyphenylpiperazine (MeOPP)
Some additional analogues include quipazine, ORG-12962, and 3C-PEP.

## Society and culture
### Legal status
#### Belgium

mCPP is illegal in Belgium.

#### Brazil

mCPP is illegal in Brazil.

#### Canada

mCPP is not a controlled drug in Canada.

#### China

As of October 2015 mCPP is a controlled substance in China.

#### Czech Republic

mCPP is legal in the Czech Republic.

#### Denmark

mCPP is illegal in Denmark.

#### Finland

mCPP is illegal in Finland.

#### Germany

mCPP is illegal in Germany.

#### Hungary

mCPP is illegal in Hungary since 2012.

#### Japan

mCPP is illegal in Japan since 2006.

#### Netherlands

mCPP is legal in the Netherlands.

#### New Zealand

Based on the recommendation of the EACD, the New Zealand government has passed legislation which placed BZP, along with the other piperazine derivatives TFMPP, mCPP, pFPP, MeOPP and MBZP, into Class C of the New Zealand Misuse of Drugs Act 1975. A ban was intended to come into effect in New Zealand on December 18, 2007, but the law change did not go through until the following year, and the sale of BZP and the other listed piperazines became illegal in New Zealand as of 1 April 2008. An amnesty for possession and usage of these drugs remained until October 2008, at which point they became completely illegal. However, mCPP is legally used for scientific research.

#### Norway

mCPP is illegal in Norway.

#### Russia

mCPP is illegal in Russia.

#### Sweden

mCPP is illegal in Sweden.

#### Poland

mCPP is illegal in Poland.

#### United States

mCPP is not scheduled at the federal level in the United States, but it is possible that it could be considered a controlled substance analog of BZP, in which case purchase, sale, or possession could be prosecuted under the Federal Analog Act.
However, "chlorophenylpiperazine" is a Schedule I controlled substance in the state of Florida making it illegal to buy, sell, or possess in this state.

#### Turkey

mCPP is illegal in Turkey since 20/05/2009.