Tropical Weight Loss
Photo by Andres Ayrton Pexels Logo Photo: Andres Ayrton

Can you gain weight while on phentermine?

If you find yourself gaining weight while taking phentermine see your doctor. Phentermine should be used alongside dietary changes, exercise, and behavioral modification as discussed with your doctor. Do not drive or operate machinery if this medicine impairs your judgment.

drugs.com - Phentermine: 7 things you should know - Drugs.com
How long does it take for L-carnitine to kick in?
How long does it take for L-carnitine to kick in?

~ 100 days Based on these results, Authors suggested that oral ingestion of LC, combined with CHO for activation carnitine transport into the...

Read More »
Last updated Jun 17, 2020
How much water should u drink a day to lose weight?
How much water should u drink a day to lose weight?

Drinking at least 64 ounces (eight cups) of water every day may help with weight loss. Downing liquid is not the only way to meet this goal. About...

Read More »
Last updated Aug 14, 2018

Phentermine: 7 things you should know

Medically reviewed by Carmen Fookes, BPharm. Last updated on Nov 3, 2021.

1. How it works

Phentermine is a central nervous stimulant that may be used to treat obesity. Experts aren't exactly sure how phentermine works but it appears to have multiple actions including stimulating neurons to release the neurotransmitters dopamine and norepinephrine, which may account for its appetite-suppressing effects. Phentermine also appears to increase levels of norepinephrine, dopamine, and serotonin by inhibiting their reuptake and inhibiting monoamine oxidase enzymes. It possibly also indirectly raises leptin levels in the brain (leptin is a hormone that tells us we feel full), and reduces the effects of neuropeptide Y - a chemical messenger that initiates eating, decreases energy expenditure, and increases fat storage.

Phentermine belongs to the class of drugs known as anorectics or anorexigenics.

2. Upsides

May be used short-term as an aid to weight-loss in addition to exercise, behavioral modification, and caloric restriction. Recommended only for people with an initial BMI of equal or more than 30 kg/m2, or 27 kg/m2 with risk factors for a cardiovascular event (such as controlled high blood pressure, diabetes, or high cholesterol).

3. Downsides

If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include: High blood pressure and other adverse cardiovascular effects. Restlessness, insomnia, headache, psychosis, dry mouth, rash, sexual dysfunction, an unpleasant taste, and gastrointestinal disturbances may also occur. Treatment of more than a few weeks increases the risk of addiction and dependence on phentermine. Abrupt cessation following prolonged dosing may cause a withdrawal effect (symptoms include extreme fatigue and depression). May impair judgment and affect a person's ability to drive or operate machinery. Alcohol should be avoided. Tolerance may develop to the weight-loss effects of phentermine, rendering it less effective. The dosage of phentermine should not be increased in this situation, rather the drug may need to be discontinued under medical advice.

Should not be used in children aged 16 or less.

The dosage of phentermine requires reducing in people with severe kidney impairment and it should be avoided in people with end-stage kidney disease. Phentermine is not suitable for people with a history of cardiovascular or valvular heart disease, glaucoma, hyperthyroidism, a history of drug abuse, who are pregnant or breastfeeding, or with agitation. May interact with a number of other drugs including other medications used for weight loss (includes other prescribed products, over-the-counter preparations, or herbal supplements), antidepressants, antipsychotics, antidiabetic drugs, and other central nervous system stimulants. Some interactions may be potentially fatal, such as primary pulmonary hypertension (PPH), a frequently fatal lung disease which can occur if phentermine is taken with fenfluramine or dexfenfluramine.

Does loose skin ever tighten?
Does loose skin ever tighten?

For small to moderate amounts of weight loss, your skin will likely retract on its own. Natural home remedies may help too. However, more...

Read More »
Last updated Aug 16, 2020
How to cut belly fat?
How to cut belly fat?

Here's how to whittle down where it matters most. Try curbing carbs instead of fats. ... Think eating plan, not diet. ... Keep moving. ... Lift...

Read More »
Last updated Dec 6, 2018

Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. View complete list of side effects

4. Bottom Line

Phentermine may be used short-term as an aid to weight loss; however, it can be addictive and tolerance may develop to its weight-losing effects, rendering it less effective with time.

5. Tips

Administer before breakfast or one-to-two hours after breakfast. Avoid late evening administration as this may cause insomnia. Some people may benefit from a twice-daily dosage regimen. Dosage must be tailored to different individuals. Take exactly as directed and for the duration intended. If you find yourself gaining weight while taking phentermine see your doctor. Phentermine should be used alongside dietary changes, exercise, and behavioral modification as discussed with your doctor.

Do not drive or operate machinery if this medicine impairs your judgment.

Do not drink alcohol while taking phentermine as it may increase the risk of side effects and further impair your judgment. Should not be used at the same time as other medications used for weight loss. Recommended only for people with an initial BMI of equal or more than 30 kg/m2, or 27 kg/m2 with risk factors for a cardiovascular event (such as controlled high blood pressure, diabetes, or high cholesterol). Do not share your phentermine with anybody else (this is also illegal). Report any new shortness of breath, angina pain, fluid retention in legs or feet, or a decrease in your ability to exercise (not attributable to any other cause) to your doctor immediately. Phentermine may be sought out by drug users and one accidental dose may be fatal to children or pets. Keep supplies out of reach and sight of others. Tell your doctor if you are pregnant, intending to become pregnant, or breastfeeding because phentermine may not be suitable for you.

Is daily burn good for beginners?
Is daily burn good for beginners?

With classes and programs that are specifically designed for novice exercisers, Daily Burn is definitely a solid choice for beginners. Whether...

Read More »
Last updated Jun 12, 2021
Who has the most beautiful skin?
Who has the most beautiful skin?

Celebrities with the Most Beautiful Skin Kim Kardashian. She has the type of creamy skin complexion that makes people jealous. ... Nicole Kidman....

Read More »
Last updated Mar 18, 2022

6. Response and effectiveness

Peak concentrations of phentermine are reached within three to four hours. Studies have shown that, on average, phentermine helps people lose approximately one extra pound per week. The rate of weight loss is greatest in the first few weeks of therapy.

7. Interactions

Medicines that interact with phentermine may either decrease its effect, affect how long it works for, increase side effects, or have less of an effect when taken with phentermine. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Common medications that may interact with phentermine include:

amphetamine

antacids

antihypertensives, such as beta-blockers

atomoxetine

bupropion

carbonic anhydrase inhibitors

dextroamphetamine

dopamine

epinephrine

ethosuximide

isoproterenol

linezolid

lisdexamfetamine

lithium

methylphenidate

monoamine oxidase inhibitors

opioids

phenylephrine

phenytoin

selegiline

tranylcypromine

venlafaxine.

Avoid drinking alcohol or taking illegal or recreational drugs while taking phentermine.

Note that this list is not all-inclusive and includes only common medications that may interact with phentermine. You should refer to the prescribing information for phentermine for a complete list of interactions.

References

Phentermine. Revised 04/2021. Drugs.com. https://www.drugs.com/ppa/phentermine.html

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use phentermine only for the indication prescribed. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Copyright 1996-2022 Drugs.com. Revision date: November 3, 2021.

Medical Disclaimer

drugs.com - Phentermine: 7 things you should know - Drugs.com
What is the fastest way to drop 5 pounds?
What is the fastest way to drop 5 pounds?

How To Lose 5 Pounds Fast Drink Two Glasses of Water Before Every Meal. ... Reduce Bloating. ... Get Eight Hours of Sleep. ... Avoid Processed...

Read More »
Last updated Jul 26, 2021
What is L carnitine good for?
What is L carnitine good for?

It helps the body turn fat into energy. L-carnitine is important for heart and brain function, muscle movement, and many other body processes. The...

Read More »
Last updated Jan 22, 2018
What is better semaglutide or Saxenda?
What is better semaglutide or Saxenda?

Liraglutide 3mg(Saxenda®) injection has to be given every day. This because Semaglutide has a longer duration of action in the body. Research shows...

Read More »
Last updated Apr 14, 2019
Does semaglutide get rid of belly fat?
Does semaglutide get rid of belly fat?

They found treatment with semaglutide improved body composition by reducing excess body fat, including abdominal fat, and increasing the proportion...

Read More »
Last updated Jan 4, 2019