What is phentermine?
Phentermine is a prescription weight loss medication.
The FDA approved it in 1959 for short-term use of up to 12 weeks for people older than16 In the 1990s; phentermine was combined with other weight loss drugs. This drug combination was commonly called fen-phen.
Phentermine goes by the brand names Adipex-P, Lomaira, and Suprenza, or you can find it in combination medications for weight loss, such as Qsymia.
More Information on Phentermine
It’s a controlled substance due to its chemical similarities to the stimulant amphetamine — making it available only with a prescription.Your doctor may prescribe phentermine if you’re obese, meaning that your body mass index (BMI) is greater than or equal to 30.
It may also be prescribed if you’re overweight with a BMI greater than or equal to 27 and have at least one weight-related condition, such as high blood pressure, high cholesterol, or type 2 diabetes
Phentermine is similar to an amphetamine. Phentermine stimulates the central nervous system (nerves and brain), which increases your heart rate and blood pressure and decreases your appetite.Phentermine is used together with diet and exercise to treat obesity, especially in people with risk factors such as high blood pressure, high cholesterol, or diabetes.
Phentermine may also be used for purposes not listed in this medication guide.
Before taking Phentermine
You should not use phentermine if you are allergic to it, or if you have:
- A history of heart disease (coronary artery disease, heart rhythm problems, congestive heart failure, stroke);
- Severe or uncontrolled high blood pressure;
- Overactive thyroid;
- Extreme agitation or nervousness;
- A history of drug abuse; or
- If you take other diet pills.
Do not use phentermine if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, tranylcypromine, and others.
Weight loss during pregnancy can harm an unborn baby, even if you are overweight. Do not use phentermine if you are pregnant. Tell your doctor right away if you become pregnant during treatment.
You should not breast-feed while using it .
Tell your doctor if you have ever had:
- heart disease or coronary artery disease;
- a heart valve disorder;
- high blood pressure;
- diabetes (your diabetes medication dose may need to be adjusted); or
- kidney disease.
How Does It Work?
Phentermine belongs to a class of drugs called “anorectics,” also known as appetite suppressants.
Taking phentermine helps suppress your appetite, thereby limiting how many calories you eat. Over time, this can lead to weight loss.
While the exact mechanisms behind the appetite-reducing effects of phentermine remain unclear, the drug is thought to act by increasing neurotransmitter levels in your brain
Neurotransmitters are your body’s chemical messengers and include norepinephrine, serotonin, and dopamine.
When your levels of these three chemicals increase, your feeling of hunger decreases.
However, you may build a tolerance to the appetite-suppressing effects of phentermine within a few weeks. In that case, you should not increase your dose of the drug but stop using it altogether.
Some Important Information about Phentermine
You should not use this medicine if you have glaucoma, overactive thyroid, severe heart problems, uncontrolled high blood pressure, advanced coronary artery disease, extreme agitation, or a history of drug abuse.
Do not use this medicine if you have used an MAO inhibitor in the past 14 days, such as isocarboxazid, linezolid, methylene blue injection, phenelzine or tranylcypromine.
Side Effects Of Phentermine
Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
- Feeling short of breath, even with mild exertion;
- Chest pain, feeling like you might pass out;
- Swelling in your ankles or feet;
- Pounding heartbeats or fluttering in your chest;
- Tremors, feeling restless, trouble sleeping;
- Unusual changes in mood or behavior; or
- Increased blood pressure–severe headache, blurred vision, pounding in your neck or ears, anxiety, nosebleed.
How should I take phentermine?
Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.
Phentermine is usually taken before breakfast, or 1 to 2 hours after breakfast. Follow your doctor’s dosing instructions very carefully.
Never use it 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.
It 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 phentermine suddenly, or you could have unpleasant withdrawal symptoms. Ask your doctor how to safely stop using this medicine.
Store at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.