Belviq vs. Adipex-P

Are Belviq and Adipex-P the Same Thing?

Belviq (lorcaserin hydrochloride) and Adipex-P (phentermine) are used for weight management in obese patients in addition to diet and exercise.

Belviq is used for chronic weight management. It is also used for patients who have at least one weight-related condition such as high blood pressure (hypertension), type 2 diabetes, or high cholesterol (dyslipidemia).

Adipex-P is used short-term treatment of obesity.

Belviq and Adipex-P belong to different drug classes. Belviq is a serotonin 2C receptor agonist and Adipex-P is an appetite suppressant.

Side effects of Belviq and Adipex-P that are similar include headache, dizziness, nausea, dry mouth, constipation, diarrhea, and vomiting.

Side effects of Belviq that are different from Adipex-P include low blood sugar (hypoglycemia), mental problems, slow heartbeat, drowsiness, feeling tired, fatigue, cough, back pain, painful erections, upper respiratory tract infection, runny or stuffy nose, urinary tract infection (UTI), muscle pain, sore throat, and rash.

Side effects of Adipex-P that are different from Belviq include upset stomach, an unpleasant taste in mouth, hives, impotence, palpitations, high blood pressure (hypertension), hyperactivity, sleep problems (insomnia), restlessness, tremors, and increased or decreased interest in sex.

Both Belviq and Adipex-P may interact with other prescription or over-the-counter weight-loss products, monoamine oxidase inhibitors (MAOIs), and antidepressants.

Belviq may also interact with triptans, cough and cold or allergy medications that contain dextromethorphan, St. John's wort, cabergoline, linezolid, lithium, tramadol, L-tryptophan, erectile dysfunction medicines, anxiety medicines, medicines to treat mental illness or a mood disorder, or "triptan" migraine headache medicines.

Adipex-P may also interact with alcohol, insulin or oral diabetes medications, and blood pressure medications.

What Are Possible Side Effects of Belviq?

Common side effects of Belviq include:

  • low blood sugar (hypoglycemia),
  • mental problems,
  • slow heartbeat,
  • headache,
  • dizziness,
  • drowsiness,
  • feeling tired,
  • fatigue,
  • nausea,
  • dry mouth,
  • cough,
  • back pain,
  • constipation,
  • painful erections,
  • diarrhea,
  • vomiting,
  • upper respiratory tract infection,
  • runny or stuffy nose,
  • urinary tract infection,
  • muscle pain,
  • sore throat, or
  • rash.

What Are Possible Side Effects of Adipex-P?

Common side effects of Adipex-P include:

  • nausea,
  • vomiting,
  • upset stomach,
  • diarrhea,
  • dry mouth,
  • constipation,
  • an unpleasant taste in mouth,
  • hives,
  • impotence,
  • palpitations,
  • high blood pressure,
  • hyperactivity,
  • sleep problems (insomnia),
  • restlessness,
  • headache,
  • tremors,
  • dizziness, and
  • increased or decreased interest in sex.

Tell your doctor if you have serious side effects of Adipex-P including:

  • shortness 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;
  • confusion or irritability, unusual thoughts or behavior;
  • feelings of extreme happiness or sadness; or
  • dangerously high blood pressure (severe headache, blurred vision, buzzing in your ears, anxiety, chest pain, shortness of breath, uneven heartbeats, seizure).

What Is Belviq?

Belviq (lorcaserin hydrochloride) is a serotonin 2C receptor agonist indicated for the treatment of chronic weight management in adults with a body mass index (BMI) of 30 or greater (obese) as an addition to a reduced-calorie diet and exercise. Belviq is also approved for use by adults with a BMI of 27 or greater (overweight) and who have at least one weight-related condition such as high blood pressure (hypertension), type 2 diabetes, or high cholesterol (dyslipidemia).

What Is Adipex-P?

Adipex/Adipex-P (phentermine) is an appetite suppressant used in combination with diet and exercise for the short-term treatment of obesity.


Weight loss occurs in the belly before anywhere else. See Answer

What Drugs Interact With Belviq?

Belviq may interact with antidepressants, including selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors (MAOIs), triptans, bupropion, dextromethorphan, or St. John's Wort. Tell your doctor all medications you use.

What Drugs Interact With Adipex-P?

Adipex may interact with insulin or oral diabetes medications or blood pressure medications. Adipex may also interact with alcohol, monoamine oxidase inhibitors (MAOIs), or antidepressants.

How Should Belviq Be Taken?

Belviq is taken orally. The recommended dosage of Belviq is one 10mg tablets taken twice per day. Belviq should be discontinued if 5% weight loss is not achieved by week 12 of therapy.

How Should Adipex-P Be Taken?

The recommended dose of Adipex-P is 30 mg once daily.


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Eisai. Belviq Product Information.

DailyMed. Adipex-P Product Information.

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