*An off-label use of a medication is a use that is not FDA-approved. Prescribers can decide to use a medication off-label because, in their professional judgment, they believe it may offer a benefit to someone.
Phendimetrazine is classified as an appetite suppressant and is a weight-management drug, specifically for patients with obesity. It works by suppressing appetite and comes in both extended-release and immediate-release forms. Patients who are hypersensitive to sympathomimetics, highly nervous, or have a history of drug abuse should avoid phendimetrazine. Some common side effects include hypertension, restlessness, insomnia, stomach pain, and frequent urination.1
Phendimetrazine tartrate is a controlled substance, which means that it’s more likely to be misused or cause dependence. There are federal and state laws that limit the amount of medication that can be prescribed or dispensed within a certain period of time.
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What Is Phendimetrazine?
Phendimetrazine is an FDA-approved medication used for weight management in obesity as a short-term treatment. FDA approval of a drug means that data on the drug’s effects have been reviewed by the FDA, and the drug is determined to provide benefits that outweigh its known and potential risks for its intended population.
Phendimetrazine is only available as a generic medication in tablet form. Only capsule forms of the extended-release form can be prescribed. Phendimetrazine works by stimulating the central nervous system to release norepinephrine, a chemical in the body that may help decrease appetite. Your doctor would use caution when prescribing this medication for you if you have high blood pressure, because this drug can exacerbate the condition or cause serious adverse effects.1
How Does Phendimetrazine Work for Weight Loss?
Phendimetrazine falls under the sympathomimetic amine drug class. This means the drug increases central nervous system stimulation. This leads to faster energy depletion or burning of calories as the body has to work harder to stimulate the central nervous system. It also suppresses appetite leading to less calorie intake. 1 Because the body develops a tolerance to the medication, the rate of weight loss is greater in the first weeks of therapy and decreases in succeeding weeks.
Side Effects of Phendimetrazine
While phendimetrazine can be effective for weight loss, like all medications, it can cause several side effects. Some side effects last for as long as a person takes the medication and some may be temporary. Long-term side effects may include high blood pressure, increased heart rate, restlessness, urinary frequency, and dry mouth. Some temporary side effects include stomach pain, diarrhea, and changes in libido (sex drive). Your doctor would use caution when prescribing this medication for you if you have a history of heart disease, thyroid abnormalities, and agitated states.1
Common Side Effects of Phendimetrazine
Common side effects of phendimetrazine include restlessness, feeling nervous, insomnia, and high blood pressure. While most of these side effects don’t need medical attention, if your blood pressure is abnormally high, you should reach out to your prescriber.1
Common side effects of phendimetrazine include:*1
- Restlessness
- Insomnia
- Dry mouth
- Constipation
- Stomach pain or diarrhea
- Nausea
- Flushing
*All medications, including phendimetrazine, can cause side effects which can be mild or serious. This is not a comprehensive list of all possible side effects. You should talk with your doctor or pharmacist about any questions you have and to understand the potential side effects and benefits of any medication.
Serious Side Effects of Phendimetrazine
Phendimetrazine may also lead to serious side effects in patients. If you have shortness of breath, chest pains, or feel faint, seek medical care immediately. These could be possible signs of pulmonary hypertension, a serious condition that elevates the blood pressure in the lungs1
Serious side effects of phendimetrazine include:*1
- Exertional dyspnea (shortness of breath)
- Unexplained symptoms of angina pectoris (chest pain)
- Syncope (fainting)
- Lower extremity edema (swelling)
- Extreme Fatigue
- Mood changes
- Urinary frequency
*All medications, including phendimetrazine, can cause side effects which can be mild or serious. This is not a comprehensive list of all possible side effects. You should talk with your doctor or pharmacist about any questions you have and to understand the potential side effects and benefits of any medication.
What Are The Long-term Effects of Taking Phendimetrazine?
Prolonged use of phendimetrazine can lead to several long-term effects, including pulmonary hypertension, vascular heart disease, and possible addiction. The use of phendimetrazine for longer than 3 months was associated with a significantly high risk of developing pulmonary hypertension. Before developing pulmonary hypertension, a person at risk will likely experience shortness of breath, chest pains, fainting, and lower extremity swelling.
Valvular heart disease is also possible with prolonged use of phendimetrazine. It should not be prescribed in patients with known heart murmur or valvular heart disease. Phendimetrazine is a controlled substance and is chemically related to amphetamines, which are stimulants. Prolonged use of phendimetrazine can lead to psychological dependence and severe social dysfunction.1
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What Are the Risks & Warnings for Phendimetrazine Tartrate?
Risk of Misuse or Dependence
To minimize the risk of overdosage, using the least amount of phendimetrazine feasible is recommended. A person’s history of substance misuse should be taken into consideration.
Risks for Those With a History of Heart Disease
Phendimetrazine should be avoided for patients with heart disease. Taking phendimetrazine may increase the risk of serious heart events, and potentially worsen existing conditions.
Risks for Those Taking Insulin or Oral Medications for Diabetes
Phendimetrazine may affect the requirements for insulin or oral hypoglycemic medications in patients with diabetes. Dosage adjustments may be needed.
Adverse Reaction With Alcohol
Phendimetrazine should not be used with alcohol as it may lead to adverse drug reactions.
Risks During Pregnancy & Breastfeeding
Phendimetrazine should not be used during pregnancy as weight loss offers no weight loss benefit and may result in harm to the fetus. Phendimetrazine may be present in human milk.
Risk of Renal Impairment (Kidney Failure)
Phendimetrazine should be used with caution in patients with renal impairment, as it may lead to elevated drug levels in these patients.
Risks to Older Adults
Due to the higher likelihood of decreased liver, kidney, and cardiac function in older adults, taking a lower dose can reduce the risk of adverse reactions.
There may be additional warnings or precautions with this medication. Talk with your healthcare provider about all the risks before you start taking this medication.
Interactions With Phendimetrazine
Phendimetrazine can interact harmfully with various medications, substances, and herbs. While taking phendimetrazine, alcohol should be avoided as it increases the risk of adverse drug reactions.
The use of other appetite suppressants can increase the risk of developing pulmonary hypertension. These are just some of the drug interactions with phendimetrazine. A provider or a pharmacist should be consulted to identify other potential drug interactions with phendimetrazine.1
Six substances you should avoid while taking phendimetrazine include:1
- Monoamine oxidase inhibitors (MAOIs): Taking a medication in this class of antidepressants with phendimetrazine can lead to a dangerous increase in blood pressure. Phendimetrazine should not be used until 14 days after the last dose of an MAOI.
- Insulin or oral hypoglycemic medications: Phendimetrazine can alter the requirements for insulin or oral medications used to lower blood sugar in diabetes.
- Adrenergic neuron blocking drugs (e.g. tamsulosin, prazosin): This type of medication is used to treat high blood pressure and enlarged prostate. Combining these medications with phendimetrazine may reduce their effectiveness.
- Guanethidine: This medication is used for the treatment of high blood pressure. Combining it with phendimetrazine may reduce its blood pressure-lowering effects.
- Other appetite suppressants: Using phendimetrazine with other weight loss medications can increase the risk of developing pulmonary hypertension, which is a rare but serious lung disorder.
This is not a comprehensive list of the possible interactions with phendimetrazine. You should talk with your healthcare provider and your pharmacist about all prescription and over-the-counter medications, herbs, and supplements you take before starting phendimetrazine.
Phendimetrazine Dosages for Weight Loss
Phendimetrazine dosages can vary based on individual factors such as age, weight, and the specific condition. The typical dosage range for adults is 35-105 mg divided into one to three doses per day. Dosage should be individualized to achieve the desired effect with the lowest effective dose. Dosages should not exceed 2 tablets of 35 mg immediate-release phendimetrazine three times daily, or one extended-release capsule of 105 mg per day.1
Phendimetrazine Forms & Strengths
Phendimetrazine comes in immediate-release and extended-release forms. Prescribers consider several factors when choosing between the two forms and doses. These include the patient’s BMI, response to previous weight-loss treatments, health history, and other risk factors.
The extended-release form provides a sustained release of the medication. This form may help maintain a more stable drug level in the body over time for better results. The immediate-release form peaks more quickly but requires more frequent dosing.1
Phendimetrazine is available in the following forms and strengths:1
- 105 milligrams (mg) extended-release capsule
- 35 milligrams (mg) immediate-release tablet
Phendimetrazine Dosages for Adults Diagnosed With Obesity
Phendimetrazine is an appetite suppressant and is FDA-approved treatment for weight loss. It works by stimulating the central nervous system to decrease appetite. The extended-release form of phendimetrazine should be taken 30-60 minutes before breakfast. The immediate-release form of phendimetrazine should be taken one hour before meals throughout the day.
Here is phendimetrazine dosage information for weight loss in adults:1
- Typical starting dosage: 105 mg extended-release capsule once daily or 17.5-35 mg immediate-release tablets two to three times daily.
- Dosage increases: The lowest effective dosage must be prescribed. Do not take more than prescribed.
- Maximum dosage: 105 mg extended-release capsule once daily or two 35 mg immediate-release tablets three times daily.
Phendimetrazine Dosages for Adolescents With Obesity
Phendimetrazine is not recommended for children under the age of 17 as its safety and effectiveness have not been studied in this population. Additionally, pediatric obesity is usually considered a long-term condition and this medication is only meant for short-term use.1
How Long Does it Take for Phendimetrazine to Start Working?
Phendimetrazine effects peak within 1 to 3 hours after ingestion and it is fully excreted from the body in less than 24 hours.2
How Do I Take Phendimetrazine for Weight Loss?
Phendimetrazine should be taken as directed by your prescriber. It is important to take this medication one hour before meals if taking it multiple times a day or 30 minutes to one hour before breakfast if taking the extended-release form for appetite suppression.1
What Happens If I Miss a Dose of Phendimetrazine?
If you miss a dose of phendimetrazine, skip the missed dose and take the missed dose at the next normal dosing time. Due to increased chances of adverse reactions, do not take 2 doses at the same time and do not take any extra doses. Do not abruptly stop taking phendimetrazine as it might lead to extreme fatigue and depression.1
How to Get Phendimetrazine for Weight Loss
To get phendimetrazine, begin with an evaluation of your weight management issues. A good place to start is with your primary healthcare provider. Your provider may refer you to a specialist who can evaluate your weight management needs and prescribe phendimetrazine, if they deem it appropriate. You and your prescriber can weigh the pros and cons of phendimetrazine and decide whether it will be part of your treatment plan.
To get prescribed phendimetrazine online, you will also start by getting evaluated by an online provider. It is important to find an online platform that will do a virtual consultation and can prescribe controlled substances for weight management, such as Circle Medical. Not all online providers offer this type of care and prescription options.
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Phendimetrazine Vs. Other Weight Loss Methods
Phendimetrazine, Wegovy, Mounjaro, and Contrave are all FDA-approved medications used for weight loss. Phendimetrazine is an appetite suppressant and works similarly to amphetamines, acting as an appetite suppressant. It is used for short-term weight loss along with dietary changes and exercise. Wegovy is a GLP-1 receptor agonist, is injected into the skin once a week, and also aids in reducing appetite.
Mounjaro is FDA approved for type 2 diabetes and weight loss. Mounjaro helps to suppress appetite to reduce body weight. Similar to Wegovy, Mounjaro is also injected into the skin. Lastly, Contrave is another medication for weight loss and it is a combination of bupropion and naltrexone. Unlike phendimetrazine, Contrave can be used for chronic weight management.1,3,4,5
Phendimetrazine in Combination With Lifestyle Changes
Phendimetrazine in combination with lifestyle changes like dietary modifications and increased physical activity can help achieve greater initial weight loss. The rate of weight loss using phendimetrazine decreases in succeeding weeks. You may find that even with an equal amount of work you are not losing as much weight as when you first start phendimetrazine.1
How to Know if Phendimetrazine for Weight Loss Is Right for You
To know if phendimetrazine is right for you, start by consulting your primary healthcare provider. Phendimetrazine is typically prescribed for short-term use with a reduced-calorie diet and exercise regimen for individuals with a body mass index of 27 or higher with additional risk factors. If your prescriber determines that phendimetrazine may be helpful for your needs, they may offer you a prescription.
Frequently Asked Questions
How Quickly Can You Lose Weight on Phendimetrazine?
While taking phendimetrazine you can expect to lose weight within the first week of taking the medication. With it being a short-term regimen, you will see the most difference in the first few weeks and the change will slow down in the succeeding weeks.1
How Much Weight Can I Lose on Phendimetrazine?
With phendimetrazine, one should expect to lose about one pound a week, with a weight loss of at least 4 pounds within the first 4 weeks of treatment, though this may differ between individual patients.1
How Effective Is Phendimetrazine for Weight Loss?
Phendimetrazine has shown effectiveness for weight loss, primarily when used as a part of a weight management program that includes dietary changes and increased physical activity. The overall effectiveness of phendimetrazine is limited due to the short duration of the clinical studies and further research is needed to fully understand its safety and long-term efficacy.1
What’s the Difference Between Phendimetrazine Vs Phentermine?
Phendimetrazine and phentermine are both appetite suppressants and work by stimulating the central nervous system to suppress appetite. Both drugs have similar adverse reactions and are pharmacologically similar to amphetamines. Phendimetrazine has a higher abuse potential than phentermine which should be considered for patients with a history of substance misuse.1,6
Does Phendimetrazine Give You Energy?
Phendimetrazine is a sympathomimetic amine that stimulates the central nervous system, which can result in increased energy levels. The primary purpose of phendimetrazine is not to provide energy but to assist in weight loss through appetite reduction and increased burning of calories.1
Questions to Ask Your Healthcare Provider About Phendimetrazine of Weight Loss
If your BMI is over 27, talk to your primary healthcare provider about getting a weight management evaluation. Your provider understands your health history and may be able to evaluate your weight management needs. Or, they may refer you to a weight management specialist to begin this process. Alternatively, if you do not have a primary provider, an online platform offering weight management treatment services can be a good place to start, such as Talkiatry and Circle Medical.
Questions to ask your care team about phendimetrazine for weight loss include:
- How safe is phendimetrazine for weight loss?
- How long does it typically take for phendimetrazine to start working, and for how long can I expect the effects to last?
- Given my weight loss goals and the underlying reasons for my weight gain (e.g., emotional eating, unhealthy eating habits), is phendimetrazine the most suitable approach?
- Are there any long-term safety concerns associated with using phendimetrazine, such as dependence or nutrient deficiencies?
- Can certain medications or supplements interact with phendimetrazine and affect its effectiveness or safety?
- Will phendimetrazine allow me to lose weight and keep it off long-term?
- Are there any interactions between phendimetrazine and other medications or supplements I am taking?
- What should I do if the prescribed dose of phendimetrazine is not working for me?
Prescriber’s Tips
In my experience, phendimetrazine is less commonly prescribed than phentermine for weight loss. While it can be effective for some individuals, its use is limited due to potential side effects and the need for close monitoring by healthcare providers due to the possibility of abuse. Follow these tips for safe and effective use of phendimetrazine.
- Take phendimetrazine as prescribed and do not change your dosage unless instructed by your prescriber.
- If you have concerns about the dosage or effectiveness of your prescription, tell your prescriber. Follow their instructions for any change made to your prescription.
- Phendimetrazine is most effective when paired with a healthy balanced diet and regular moderate exercise.
- Discuss the potential common and serious side effects of phendimetrazine with your prescriber before beginning your treatment.
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Label: phendimetrazine tartrate capsule, extended release. (August 24, 2023). DailyMed.nlm.nih.gov. Retrieved from https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm
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Phendimetrazine: Uses, Interactions, Mechanism of Action. (February 24, 2024). DrugBank.com. Retrieved from https://go.drugbank.com/drugs/DB01579
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Label: Mounjaro – tirzepatide injection, solution. (September 22, 2023). Dailymed.nlm.nih.gov. Retrieved from https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm
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Label: Wegovy – semaglutide injection, solution. (March 1, 2024). DailyMed.nlm.nih.gov. Retrieved fromhttps://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm
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Label: Contrave extended-release – naltrexone hydrochloride and bupropion hydrochloride tablet, extended release. (May 21, 2024). DailyMed.nlm.nih.gov. Retrieved from https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm
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Label: Phentermine hydrochloride capsule. (April 18, 2024). DailyMed.nlm.nih.gov. Retrieved from https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm
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Semaglutide: Uses, Side Effects, Interactions, & More
Understanding the complexities of medications like semaglutide is crucial for anyone seeking effective treatment. It’s important to acknowledge that semaglutide is extensively used in managing type 2 diabetes and obesity, with potential benefits in weight loss and cardiovascular risk reduction.
Mounjaro Weight Loss: Safety, Side Effects, & More
Mounjaro is a relatively new medication that is within a class of medications known for their control of blood sugar and potential for managing weight. It’s unique in that it has two different ways of working in the body. It is generally recommended that patients make lifestyle choices alongside any medications used for weight management.
