Qnexa

What is Qnexa?

Qnexa is a new slimming pill currently being assessed by the Food and Drugs Administration in the U.S. We expect that if Qnexa is approved for use in the United States then an application will be filed in the European Union. Qnexa has been developed by Vivus, a fast-growing pharmaceutical research company based in North America. Qnexa is designed to help obese patients reduce their appetite and feel satisfied with less food. It comes in capsule form and is taken daily.

How does Qnexa work?

Qnexa contains two active ingredients, phentermine and topiramate. Phentermine used to be a commonly prescribed slimming medication until about a decade ago, when concerns were raised about its impact on long-term health and whether it is addictive. Phentermine is no longer generally prescribed in the UK but there are some specialist slimming clinics that prescribe this medication for very short-term use. Phentermine is still the most commonly prescribed weight loss medication in the United States. Topiramate was approved in 1996 as a treatment for epilepsy and more recently as a treatment for migraine prevention.

Topiramate works through GABA receptors in the brain to increase feelings of satiety and fullness. Phentermine stimulates the release of the neurotransmitter noradrenalin, which reduces appetite. The combination of Topiramate with Phentermine appears to increase Topiramate's window of effectiveness.

Is Qnexa effective?

Qnexa has gone through two separate phase III clinical trials required by the FDA and results from the trials indicated that it is an effective aid to weight loss in obese patients.

In the EQUIP trials, lasting 56 weeks and involving 1,267 obese patients, data showed that:

• On average patients taking the drug at full strength lost 14.7% of their body weight, compared with 2.5% for those on the placebo over the 56-week period
• 84% of patients on the highest dose lost 5% or more of their total body weight, with 59% on the lower dose achieving the same results, compared with only 26% in the placebo group achieving the same result
• Average weight loss for the high-dose group was 37 pounds, 18 pounds for the low dose group and 6 pounds for the placebo group

In the CONQUER trials, involving 2,487 patients with co-morbidities such as high blood pressure, Type 2 Diabetes and high cholesterol, the results were as follows over a 56 week period:

• Patients lost 13.2% of their total body weight on the high dose, 10.5% on the lower dose and 2.4% on the placebo
• 85% of patients on the high dose and 75% on the lower dose lost 5% or more of their body weight, compared with 26% in the placebo group

Is Qnexa safe?

As with any medication, Qnexa does seem to have some side effects in some patients. The most common were dry mouth, tingling sensations, constipation, altered taste and insomnia. The medication did not seem to cause problems with mood, depression or suicidal ideation.

There had been concern about side effects reported previously with Phentermine - raised blood pressure - and Topiramate, namely cognitive problems and depression. However both drugs are present in Qnexa in very low doses and there has been no indication in the clinical trial data that the medication causes any of these, or any other, serious side effects.

The Online Clinic has always opposed the prescription of Phentermine on its own but if this new sustained release formulation in combination with Topiramate is deemed to be safe and effective then we will give serious consideration to prescribing it once the medication has been approved by the European Medicines Agency and the MHRA.

When will Qnexa be available?

Vivus has presented the findings from the clinical trials to the FDA for approval. They say that they have exceeded the FDA benchmarks as to effectiveness (the drug must have a 5% or better weight loss reported than amongst the placebo group.) At the current time we are not aware of any application the European Union for a license but we expect this to follow in the near future.

Register your interest in Qnexa

Although we cannot prescribe Qnexa at the moment, if you register for a weight loss consultation now and agree to be on our mailing list then we will notify you as soon as Qnexa becomes available.