Phen is an abbreviation of anorexigenic agent – Phentermine. This abbreviation has first been used in the USA. The abbreviation “Phen” is very often used in the combination with an abbreviation of anorexigenic agent – Fenfluramine – «Fen».
«Phen-Fen» is an abbreviation for the combination of two different anorexigenic agents – Phentermine and Fenfluramine. Until 1997, the combination of anorectic drugs «Phen-Fen» has been successfully used for the obesity treatment in adult Americans.
In 1997, data was published that many obese Americans treated with “Phen-Fen” developed cardiac valvulopathy, which requires aortic valve surgery.
It is noteworthy that 98% of all cases of cardiac valvulopathy caused by Phen-Fen were diagnosed in obese women. Moreover, the results of studies have demonstrated that:
- When using only Phen (Phentermine), cardiac valvulopathy does not develop.
- When using only Fen (Fenfluramine), cardiac valvulopathy develops in rare cases.
- When using the combination of Phen-Fen, the risk of cardiac valvulopathy increases by several times.
Guided by the results of clinical trials, the FDA has decided to withdraw Fen anorexigenic drug from the US market, but to continue the commercialization of Phen anorexigenic diet pills.
After the sale of Fen in the USA was discontinued, the cases of cardiac valvulopathy in obese patients using Phen have not been registered. In 2015, the FDA still believes that the benefits of Phen exceed its potential risks.
So, Phen is still used for the obesity treatment in the USA. While in the Europe, this anorexigenic drug was recognized as unsafe and its supplies at the European pharmaceutical market were discontinued more than 10 years ago.
After many years since the Phen withdrawal from the European market, this anorexigenic drug can come back on the market in the EU countries. For already several years, pharmaceutical company Vivus tries to get the Marketing Authorization Application (MAA) for new anti-obesity drug called Qsiva in the Europe.
Qsiva is an innovative drug, which in addition to Phen contains an active ingredient Topiramate (the abbreviation: TPM). Combined Phen-TPM diet pills by Vivus have already been approved by the FDA and sold under the trade name Qsymia in the USA.
Despite the fact that the FDA has confirmed a favorable benefit-risk balance of Qsymia (Phen-TPM) for obese patients, members of the European Committee for Medicinal Products for Human Use believe that long-term cardiovascular and psychiatric effects of Qsiva (Phen-TPM) are not sufficiently studied.
Qsymia and Qsiva are absolutely identical anti-obesity drugs containing the same doses of active ingredients Phen and TPM. Given the fact that Qsymia pills are sold in the USA for already several years, while a product license for Qsiva in the Europe has not yet been issued. It can be concluded that safety requirements for diet pills are different in the USA and Europe.
It is not excluded that after the results of Qsymia (Phen and TPM) long-term post-marketing studies in the USA, Vivus again will try to get the product license for Qsiva (Phen and TPM) in the Europe.
Current information about the approval of new Qsiva diet pills (Phen and TPM) in the EU, and the commercialization of Qsymia (Phen and TPM) in the USA you will be able to find in our reviews.