Both preparations are designed for the same purpose – weight loss management and obesity treatment; in a better part of clinical cases they could be referred to as interchangeable. Adipex, a branded drug marketed by Gate Pharmaceuticals in the US, is based on phentermine hydrochloride, while Qsymia represents a double-component drug with phentermine and topiramate as active substances.
In the US the drug is marketed by VIVUS, Inc.; just like Adipex, it is available by prescription only. While phentermine’s parent compound is amphetamine, and the component is referred to appetite suppressants group, topiramate is the active ingredient of many seizure medications, such as Topamax, referred to anticonvulsant category. Unlike Adipex that comes in 37.5mg capsules with 31mg of phentermine, Qsymia features only 3.75mg of the aforementioned ingredient and 23mg of topiramate (although you can make a choice in favour of 7.5/46mg, 11.25/69mg and 15/92mg options).
In 2014 – 2015 a 56 weeks clinical trial was conducted to evaluate the effectiveness of Qsymia, which says people have managed to lose 10% of weight or 24lb on average. A direct impact on the results is made by the dosage (the top dosage provides twice as better results in comparison with the starter one). Adipex in its turn is designed for short term use only – its treatment course should not go beyond several weeks (as a rule, 3-5 weeks), while the average weight loss results you can count on according to clinical trials is 3.5%.
Considering the drugs from a pricing point of view, Adipex may seem to be a more economically feasible option. A 30-days course of Qsymia will cost you around $135 according to WebMD, while Adipex course for the same period will be more than 2 times cheaper – around $59. Taking into account the short-term nature of treatment, the advantage could be obvious. Another weak point of Qsymia is the risk of significant side effects: topiramate may provoke suicidal thoughts and depressive conditions regardless of the dosage.
Acute myopia associated with secondary angle closure glaucoma can be another negative aspect of taking the drug. In phentermine-based Adipex these adverse are not manifested, although it implies a higher risk of insomnia (that’s why it is recommended to be taken during the morning hours). According to Drugs.com users review, Adipex is rated 9.1 vs 7.2 in Qsymia.