Phentermine A Comprehensive Guide to the Weight Loss Drug


Weight loss medications such as semaglutide and liraglutide have soared in popularity this past year. In line with rising obesity rates, many public figures have praised the aforementioned drugs for their weight loss efficacy. Their popularity has even prompted drug manufacturers to develop more convenient forms of the medication, such as an oral version of Ozempic.

While semaglutide and liraglutide drugs made recent waves online, there is a similar medication that has been used in circulation for longer that deserves the same recognition for its role in medical weight loss. This drug is called phentermine, and it has been proven to yield results on par with more popular weight loss medications, which this article will discuss in further detail.

Phentermine: A Recognized Treatment for Weight Loss

Phentermine belongs to a class of medications called anorectics and is prescribed to help patients reduce their weight. It has been around since 1959 and was first introduced as part of an anti-obesity combination drug. Since then, phentermine has been popularized as a short-term treatment to address excess weight.

In contemporary times, phentermine is commonly used within medical weight loss programs. A medical weight loss program is a doctor-led initiative designed to help patients who are categorized as having a body mass index (BMI) of 30 or higher. However, those with a BMI of 27 to 29 and have health conditions such as high cholesterol, type 2 diabetes, and other related comorbidities can be considered for medical weight loss. Unlike traditional methods, medical weight loss targets biological factors that may hinder the process of getting to a healthier weight.

How phentermine works to aid weight loss

As a weight loss drug, phentermine is used to suppress appetite and help patients feel full for longer. It works by blocking the brain’s hunger signals by promoting the release of catecholamines within the body. In doing so, it stimulates the central nervous system (including the brain and nerves), which increases blood pressure while decreasing appetite.

Phentermine is sometimes combined with topiramate to create a more effective method to address excess weight. Such is the case with Qsymia for weight loss, which is an FDA-approved drug that uses both phentermine and topiramate for obesity. A study published in the Annals of Pharmacotherapy showed that a patient can lose around 10% to 11% of their total body weight after a year of taking the max dose (15mg phentermine/92mg topiramate) of Qsymia every day. However, adopting the right lifestyle changes, such as a healthy diet and regular exercise, is pertinent to see sustainable weight loss changes throughout the body.

Qsymia is also taken orally through capsules and administered with a daily dose. This makes it easier for some patients to take their prescription, as the aforementioned semaglutide medications are mostly self-administered, weekly injectables. Additionally, semaglutide is also used by diabetics, which could make the drug difficult to access in the event of a shortage. This is not a problem for Qsymia, since it was developed with weight loss in mind and was designed specifically to help obese patients.

Special precautions and considerations before taking phentermine

Before considering phentermine for weight loss, it is important to consult closely with a medical professional, typically a doctor. Generally, though, those who are pregnant are not recommended to take this medication, as weight loss can affect the unborn baby’s well-being. Additionally, those with a known allergy to phentermine, any other medications, or any of the ingredients in phentermine tablets should first ask for a list of ingredients to ensure they won’t have detrimental health effects once taken.

Furthermore, since phentermine stimulates the central nervous system and can increase blood pressure, it is important to tell your doctor if you have a history of heart disease, high blood pressure, glaucoma, and extreme nervousness. You must also inform your doctor if you’re taking medication like Lopressor. As explained in our past post, called “Metoprolol Side Effects Demystified A Comprehensive Guide”, this is a drug widely used to treat heart conditions. Taking phentermine alongside such medications can lead to either negating or increasing the effects of the other. This can result in issues like palpitations, dizziness, or hypertension.

Common side effects to consider

No drug is without its side effects. As per GoodRx, common phentermine side effects include dry mouth, headaches, insomnia, and tremors. You can easily avoid these by talking with your doctor and coordinating with them to monitor your dose of the drug and curb any further health complications while using phentermine.