What is phentermine?
Phentermine is a weight loss prescription drug that comes as an oral capsule, an oral tablet, and an orally disintegrating tablet. Phentermine oral capsule is available as the brand-name drug Adipex-P. It’s also available as a generic drug. Generic drugs usually cost less than the brand-name version. In some cases, they may not be available in every strength or form as the brand-name drug.
Like other prescription weight-loss drugs, phentermine is intended to be used as part of an overall weight-loss plan. It is indicated for people who are obese, and who have failed to lose enough weight with diet and exercise alone — not for people who want to lose just a few pounds. Phentermine is a Schedule IV drug, a classification given to drugs that have a potential for abuse, although the actual potential appears to be low.
How does phentermine work?
Phentermine belongs to a class of drugs called anorectics. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.
It isn’t known exactly how phentermine works to help you lose weight. It may work by increasing the release of chemicals in your brain that help reduces your appetite. This may help you eat less, which would aid in weight loss.
How should I take phentermine?
Take phentermine exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.
Doses are normally taken before breakfast, or 1 to 2 hours after breakfast. Follow your doctor’s dosing instructions very carefully.
Never use phentermine in larger amounts, or for longer than prescribed. Taking more of this medication will not make it more effective and can cause serious, life-threatening side effects.
This medicine is for short-term use only. The effects of appetite suppression may wear off after a few weeks.
Phentermine may be habit-forming. Misuse can cause addiction, overdose, or death. Selling or giving away this medicine is against the law.
Call your doctor at once if you think this medicine is not working as well, or if you have not lost at least 4 pounds within 4 weeks.
Do not stop using this medicine suddenly, or you could have unpleasant withdrawal symptoms. Ask your doctor how to safely stop using this medicine.
What does phentermine do to the body?
Phentermine works by decreasing your appetite, increasing the amount of energy used by your body, and by affecting certain parts of the brain. Phentermine oral capsule should only be used short-term (for a few weeks) to treat obesity, although, new studies indicate that when used as an adjunct to lifestyle intervention, phentermine leads to greater mean weight loss and an increased likelihood of achieving clinically-meaningful 1-year weight loss.
This drug aids in weight loss in very obese and overweight people with certain health risk factors. These risk factors include high blood pressure, high cholesterol, and diabetes. This drug is used along with exercise, a low-calorie diet, and other behavior changes to lose weight.
What are phentermine’s side effects?
Phentermine can cause several side effects. Common side effects of phentermine can include:
• Changes in libido
• Constipation
• Diarrhea
• Dry mouth
• Fast heartbeat or heart palpitations
• Feeling restless
• Headache
• Higher blood pressure
• Nausea
• Tremors (shakiness)
• Trouble sleeping
Serious side effects may include:
• Psychosis (a condition that causes mental confusion and possibly hallucinations)
• Heart disease
• Pulmonary hypertension (high blood pressure in the lungs that can make breathing harder)
Phentermine may cause other side effects. Call your doctor if you have any unusual problems during your treatment with phentermine.
If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration’s (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).
