Phentermine vs Diethylpropion – (Can They Be Combined?)

  • By: jacob foxx
  • Date: April 14, 2023
Phentermine vs Diethylpropion

Phentermine and diethylpropion can offer a solution for those struggling with obesity. As anti-obesity drugs, they work to suppress hunger and aid in weight loss.

While both are available by prescription, it is worth noting that phentermine has been found to be cheaper and more effective than diethylpropion.

Additionally, phentermine has the added benefit of potentially being prescribed for certain diseases associated with obesity, providing further relief beyond just weight loss. 

As a result, in this post, I will analyze the benefits, safety, user reviews, cost, and a summary of all the pros and cons of these two pharmaceuticals in order to help you better understand the two potential treatment alternatives your doctor may prescribe you.

So, read on to find out everything you need to know.

What is Phentermine?

Phentermine is a drug that falls under the category of anorectics and is classified as Schedule IV.

The FDA has approved this drug for short-term weight loss treatment since 1959, and it is available under various brand names.

Phentermine works by stimulating the release of catecholamines, such as dopamine, epinephrine, and norepinephrine, which help suppress appetite and increase energy levels.

This drug comes in different forms, including tablets, capsules, and extended-release capsules, with the dosage ranging from 4 mg to 40 mg.

As the dosage regimen for phentermine differs from person to person, it is usually recommended to be taken once or twice a day with breakfast or before meals for the best results.

What is Diethylpropion?

Diethylpropion is an appetite suppressant that aids in the treatment of exogenous obesity through a short-term course of 12 weeks.

As an anorectic, it falls under the Schedule IV controlled substances category at par with amphetamine.

The medicine is only prescribed to patients with a BMI higher than 30 kg/m2, where diet and exercise alone do not offer results. The US FDA approved diethylpropion in 1959, but later withdrew its approval in 2007.

While still-available generic versions can be found in some markets, the FDA strongly advises against the use of these generics.

By stimulating the release of catecholamine hormones such as dopamine and norepinephrine, diethylpropion suppresses the effects of neuropeptide Y while also increasing leptin levels.

Oral forms with 25 mg of an extended-release formula are available and should be taken an hour prior to meals.

Which is safer: phentermine or diethylpropion?

When it comes to comparing drugs, it’s important to take into account a variety of factors, including benefits, safety profiles, and user reviews.

While both drugs may have their own strengths and weaknesses, one stands out as having more benefits and a better overall safety profile.

This drug has been proven to be effective in treating the condition it is intended for while also minimizing potential side effects.

Users have praised it for its ease of use and overall effectiveness. However, it’s important to note that every individual is different, and what works well for one person may not work as well for another.

Diethylpropion vs. Phentermine: Conditions Treated

Diethylpropion and phentermine are two medications that can help those who are significantly overweight shed extra pounds and improve their overall health.

To qualify for the medication, patients must either be obese or have other risk factors such as hypertension, diabetes, or hyperlipidemia.

BMI, or body mass index, is used to determine if a person falls into the overweight or obese categories, with a range of 18.5-24.9 being considered normal.

With the help of these medications and lifestyle changes, those struggling with weight-related health issues can take steps towards a healthier and happier life.


Obesity is a medical condition characterized by excessive fat accumulation that can significantly impact one’s optimal health.

The common metric used to diagnose obesity is a body mass index (BMI) of 30 or higher. There are three classes of obesity, ranging from class 1 with a BMI of 30 to 34.9 to class 2 with a BMI of 35 to 39.9 to class 3 with a BMI of 40 or higher.

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The consequences of obesity can affect an individual’s health in several ways, including an increased risk of developing chronic conditions, such as diabetes, stroke, heart disease, and some types of cancer.

Moreover, individuals diagnosed with obesity also have a higher likelihood of facing mental health issues than those who maintain a healthy weight. 

Overweight with other risk factors

According to the Centers for Disease Control and Prevention (CDC), individuals with a body mass index (BMI) between 25 and 29.9 are considered overweight.

While being overweight can lead to several health problems, such as heart disease and stroke, diethylpropion and phentermine are not typically prescribed for weight loss treatment in this BMI range.

Instead, in order for medical professionals to advise taking these medications, additional risk factors like high blood pressure, diabetes, and high cholesterol must also be present.

As such, maintaining a healthy BMI and managing any underlying health conditions may be critical to achieving optimal overall health.

How Diethylpropion and Phentermine Work

Diethylpropion and phentermine are two of the most commonly-prescribed appetite suppressants.

These drugs are thought to work by targeting certain neurotransmitters in the brain, including serotonin, norepinephrine, and dopamine.

By either inhibiting or increasing these neurotransmitters, diethylpropion and phentermine can help reduce feelings of hunger and promote weight loss.

Clinical trials have shown that when these neurotransmitter levels are increased, people tend to feel less hungry, leading to a decreased caloric intake and ultimately, weight loss.

Diethylpropion and Phentermine Side Effects

Diethylpropion and phentermine are two medications used to suppress the appetite and aid in weight loss.

Both medications have similar side effects, but there are some differences between them. It is important to understand the potential side effects of these drugs before taking them.

The below information will provide an overview of diethylpropion and phentermine side effects.

Diethylpropion Side Effects

Diethylpropion is a medication prescribed for weight loss that can help patients reach their goals quickly and safely. As with any medication, it comes with potential side effects, which range from mild to severe.

The most common side effects of diethylpropion include:

  • Dry mouth
  • Constipation
  • Headache
  • Difficulty sleeping
  • Loss of appetite
  • Increased blood pressure or heart rate
  • Lightheadedness or dizziness
  • Anxiety or restlessness
  • Sexual dysfunction in men and women
  • Difficulty concentrating or paying attention

In addition to these common side effects, diethylpropion has the potential to cause more serious complications such as stroke, chest pain, confusion, and depression. If you experience any of these symptoms while on the medication, it is important to seek medical attention immediately.

Everyone reacts differently to medications, so your individual experience could differ from those listed above.

To maximize the chances of a positive outcome, it is important to speak with your doctor about the risks and benefits before starting treatment.

Phentermine Side Effects

Phentermine is a prescription medication used to treat obesity. It is an appetite suppressant that works by affecting the central nervous system. While it can be effective in helping people lose weight, it also comes with some side effects.

Some of the most common side effects of phentermine include:

  • Dizziness
  • Dry mouth
  • Difficulty sleeping
  • Irritability
  • Nausea
  • Vomiting
  • Diarrhea
  • Constipation
  • Increased blood pressure.

In addition to these more common side effects, there are other potential risks associated with taking phentermine. These include:

• Mouth pain

• Dizziness

• Higher heart rate

• Constipation

• Insomnia

• Bad taste in your mouth

• Headache

• Vomiting

• Increased or decreased interest in sex

It’s important to talk to your doctor before taking phentermine so they can assess your individual risk factors and determine if this medication is right for you. They can also provide guidance on how to reduce any potential side effects you may experience while taking the drug.

Diethylpropion vs. Phentermine: Use

Diethylpropion and phentermine are two prescribed medications that serve as powerful tools for weight loss.

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These medications are most effective when used in conjunction with a balanced diet or exercise routine.

Diethylpropion can be taken in immediate-release or extended-release forms and can be taken three times a day before meals or once per day mid-morning, respectively.

On the other hand, phentermine is typically taken once daily, an hour before breakfast, or three times per day.

However, it’s important to note that the sustained-release version of phentermine should be taken 10-14 hours before bedtime.

It’s essential to remember that both medications should only be used for a few weeks at a time.

Diethylpropion vs. Phentermine; Which works better?

Diethylpropion and phentermine have been the subject of several comparative studies when it comes to weight loss effectiveness.

In one particular study, patients who took phentermine achieved significant weight loss and outperformed those who took diethylpropion over the course of 12 weeks.

The majority of weight loss occurred during the final four weeks of the study. Patients who took phentermine also saw significant reductions in blood pressure and resting heart rate, while the diethylpropion group only saw a decrease in heart rate.

While these reductions could be attributed to weight loss alone rather than the effects of the medications, the findings indicate that phentermine may be a more effective option for weight loss and addressing associated health concerns.

Diethylpropion vs. Phentermine: Cost

For those who struggle with weight loss, prescription medications can be an affordable option.

Two such options are generic phentermine and diethylpropion. The cost of diethylpropion can vary depending on the type of release, with an immediate release version costing around $15/month and an extended-release version costing approximately $58.

On the other hand, generic phentermine is even more affordable, costing less than $15 for a one month supply.

Keep in mind that both medications are short-term use drugs that are only meant to be taken for a few weeks.

The good news is that most commercial insurance plans, as well as Medicaid and Medicare, typically cover these generic medications.


Whenever it comes to weight loss medication, a thorough evaluation of a patient’s medical history and potential risks is necessary to choose the most suitable treatment.

Clinical evidence states that phentermine is the preferred weight loss drug compared to diethylpropion due to its effectiveness at lower dosages and ability to be used in comorbid patients.

Although diethylpropion is a safer option for pregnant women, lifestyle changes such as diet and physical activity, along with a doctor’s supervision, should accompany any treatment option.

With the right medical guidance and support, individuals can reach their weight loss goals and obtain a healthier lifestyle.

I'm Jacob Foxx, a proud native of the outskirts of Chicago, Illinois. I was enamored with the expansive Star Trek universe and its promise of cutting-edge technology and space travel from a young age. This early fascination with science fiction sparked my imagination and laid the foundation for my writing career. Alongside my love for the cosmos, I developed a passion for fitness in my formative years.

This dual interest in the world of tomorrow and the pursuit of physical health has greatly informed my writing, allowing me to explore themes of human potential and the future of our species. As an author, I strive to blend these passions into compelling narratives that inspire readers to dream and to push their own boundaries.

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