Table of ContentsView AllTable of ContentsWhat Is Phentermine?How Does Phentermine Work?How to Take ItSide Effects and Safety
Table of ContentsView All
View All
Table of Contents
What Is Phentermine?
How Does Phentermine Work?
How to Take It
Side Effects and Safety
Phentermine, available under the brand names Lomaira or Adipex-P, is a prescription medication used in combination with a healthy diet and exercise to help with weight loss in people withobesity.
This article discusses how phentermine works to help you lose weight.
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Phentermine is often prescribed to promote weight loss in people with obesity or overweight status with additional health problems. Typically, it will be recommended if you have already tried lifestyle changes to lose weight.
When determining if you need to take phentermine, your healthcare provider may look at yourbody mass index (BMI)value first. Phentermine may be prescribed if you:
Phentermine and Topiramate
Phentermine is sometimes combined with topiramate, an antiseizure medication, for weight loss. This medication combo is marketed under the name Qysmia. Unlike phentermine as a single-agent therapy, this combination is approved for long-term weight management.
Moreover, adding topiramate to phentermine is thought to enhance weight loss effects at lower doses than phentermine or topiramate alone.
About BMIBody mass index (BMI)is a dated, biased measure that doesn’t account for several important factors, such as body composition, ethnicity, race, gender, and age. Despite being a flawed measure, BMI is widely used today in the medical community because it is an inexpensive and quick method for analyzing potential health status and outcomes.
About BMI
Body mass index (BMI)is a dated, biased measure that doesn’t account for several important factors, such as body composition, ethnicity, race, gender, and age. Despite being a flawed measure, BMI is widely used today in the medical community because it is an inexpensive and quick method for analyzing potential health status and outcomes.
How Does Phentermine Work in the Body?
Phentermine belongs to a class of medications called indirect sympathomimetics. Sympathomimetics activate thesympathetic nervous system. Indirect sympathomimetics act indirectly on different receptors.
Phentermine has been shown to work in the central nervous system to help reduce appetite. Studies have shown that it acts on thehypothalamus. Phentermine stimulates the release of chemical neurotransmitters in the brain, such as norepinephrine, suppressing appetite.
A decrease in appetite will help reduce the amount of calories you eat, which may contribute to weight loss. This medication should be used alongside a reduced-calorie diet and regular exercise.
How Long Does It Take to Work?
Phentermine has been shown to start working in the body within three to four hours.You may notice effects within a few days. However, it may take a few weeks to see some weight loss.
Phentermine is only meant for short-term use–usually less than 12 weeks at a time.However, phentermine combined with topiramate may be a longer-term solution for adults needing chronic weight management.
Reducing daily calorie consumption and performing regular exercise while taking phentermine may speed up weight loss.If you don’t notice any weight changes, or if you experience any issues with this medication, contact your healthcare provider.
How to Take Phentermine
Lomaira is usually taken as 8 milligrams (mg) three times daily 30 minutes before meals.
For Adipex-P (another brand name for phentermine), the recommended adult dose for weight loss ranges from 15 milligrams to 37.5 milligrams once daily before breakfast or one to two hours after breakfast. Taking this medication late in the day may cause trouble sleeping.
Although phentermine may be effective for weight loss, it is also known to cause a few side effects.
Phentermine is associated with the following side effects:
It is important to talk to your healthcare provider if you experience any of these side effects or are allergic to this medication. Phentermine also has a high risk for addiction and abuse; therefore, you should not take it for longer than the prescribed duration. If you have a substance use disorder (such as overuse of or addiction to drugs or alcohol), this risk may be higher.
Who Can Take Phentermine?
People with obesity or overweight status with other health conditions may be eligible to take phentermine for weight loss after experiencing no positive results with lifestyle changes such as a healthy diet and exercise.
Do not take phentermine if you have a history of:
Phentermine can interact with a type of drug class known asmonoamine oxidase inhibitors (MAOIs). Do not take it during or within 14 days of MAOI therapy.
You should also avoid taking phentermine if you are pregnant or nursing.
Summary
Phentermine is a prescription medication that can help promote weight loss. It works in the central nervous system to stimulate certain chemicals that help suppress appetite.
While weight loss medications can be an effective treatment for people with obesity, it’s important to make healthy lifestyle choices to help further along your weight loss journey. This can include making a nutritious eating plan or adding more physical activity to your routine.
Consider working with a registered dietitian nutritionist (RDN) to come up with a safe and healthy diet plan for weight management. Talk to your healthcare provider if you are taking phentermine and do not notice any effects.
Frequently Asked QuestionsPhentermine should be avoided during pregnancy. It can potentially harm the fetus due to weight loss.Some studies have shown that using phentermine for longer than three months is both effective in weight loss and safe.However, long-term use of phentermine may increase the risk of side effects.Qysmia, the combination of phentermine and topiramate, has been approved as a long-term alternative for weight management.Many factors can contribute to weight management, so making healthy lifestyle choices is important when starting your weight loss journey. Medications can be an effective aid for people with obesity, but they are not a cure-all. Address any underlying contributing factors, such as diet and exercise, that can facilitate weight loss and help you keep the weight off once you stop taking pharmacological treatment.Drinking alcohol while taking phentermine may result in serious side effects, including stomach issues, dizziness, irregular heartbeat, and other side effects. Alcohol can worsen phentermine’s side effects.
Frequently Asked Questions
Phentermine should be avoided during pregnancy. It can potentially harm the fetus due to weight loss.
Some studies have shown that using phentermine for longer than three months is both effective in weight loss and safe.However, long-term use of phentermine may increase the risk of side effects.Qysmia, the combination of phentermine and topiramate, has been approved as a long-term alternative for weight management.
Many factors can contribute to weight management, so making healthy lifestyle choices is important when starting your weight loss journey. Medications can be an effective aid for people with obesity, but they are not a cure-all. Address any underlying contributing factors, such as diet and exercise, that can facilitate weight loss and help you keep the weight off once you stop taking pharmacological treatment.
Drinking alcohol while taking phentermine may result in serious side effects, including stomach issues, dizziness, irregular heartbeat, and other side effects. Alcohol can worsen phentermine’s side effects.
The author would like to recognize and thank Ghassan Alyaseen for contributing to this article.
8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
DailyMed.Label: Adipex-P- phentermine hydrochloride tablet, Adipex-P- phentermine hydrochloride capsule.
Bray GA, Ryan DH.Update on obesity pharmacotherapy.Ann N Y Acad Sci. 2014;1311:1-13. doi:10.1111/nyas.12328
Kim S.Drugs to treat obesity: do they work?Postgrad Med J.2016;92(1089):401-406. doi:10.1136/postgradmedj-2015-133388
Food and Drug Administration.Qysmia label.
Food and Drug Administration.Phentermine label
DailyMed.Label: Lomaira- phentermine hydrochloride tablet.
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