Medical Advice

Belviq vs Phentermine (Comparing Two Weight Loss Medications)

Belviq vs Phentermine

Obesity is a problem that causes high blood pressure, high cholesterol, sleep apnea, asthma, etc. in a person. Belviq and Phentermine are the two medication drugs that are responsible for the treatment of obesity in individuals. Both medicines have different styles of treatment. Also, the prescriptions of these medication drugs are different. Now, we are going to provide a brief description of these two medication drugs with its physical properties. Also, we are going to describe a comparison between the two drugs ‘Belviq vs Phentermine’ in this blog.

Description of Belviq Medicine:

Belviq medicine is a branded drug that contains an active ingredient called Lorcaserin. People take this medication drug to reduce their weight.

Belviq medicine acts as a serotonin 5-HT2C agonist in the Central Nervous System (CNS). It reduces appetite by affecting chemical signals in an individual’s brain.

Description of Phentermine Medicine:

People use Phentermine medicine when they are suffering from an obesity condition. The function of this medication drug is to stimulate the brain of an individual and nerves which helps to reduce weight in him or her. This medication drug also contains some inactive ingredients which include FD&C Blue # 1, magnesium stearate, lactose monohydrate, titanium dioxide, corn starch, D & C Red # 33, and so on.

Comparison Between Belviq vs Phentermine Medicines

Belviq and Phentermine medicines can be compared in seven different ways. These are as follows:

FDA approval

Phentermine was approved by the Food and Drug Administration (FDA) in the year 1973, whereas Belviq has no FDA approval.

Brand names

There is no brand name for Belviq medicine, while Phentermine medicine consists of nine different brand names such as Atti-Plex P, Adipex P, Phentercot, Lonamin, Pro-fast, Fastin, Lomaira, Adipex, and Phentride.

Dosages: Belviq vs Phentermine

The dosage strengths of these two medication drugs are different. Read the following dosage strengths in detail:

Belviq Medicine

There are different dosages that are available in the treatment of obesity in adults. The forms of this drug are immediate-release and extended-release oral tablets.

The dosage strength of an immediate-release oral tablet is 10 mg, whereas the dosage strength of an extended-release oral tablet is 20 mg. The starting recommended dose of 10 mg can be taken by the adults two times a day.

Phentermine Medicine

Phentermine medicine can be taken by adults and children above 17 years of age. This medication drug is in the form of oral tablet and capsule. The dosage strengths which are available in the oral tablets are –

The dosage strengths of oral capsules are as –

The half-life of Belviq and Phentermine

The half-life of Belviq medicine is 11 hours when an individual takes this medication drug for the treatment of obesity.

Phentermine medicine has a half-life of 34 hours in an individual’s body.

Drug Interactions

Both Belviq and Phentermine medicines can interact with different medicinal drugs. Read the following drug interactions of these two medication drugs:

Belviq Medicine

Belviq medicine can interact with various medicinal drugs. Some of these drugs are Chlorpheniramine, Doxepin, Cocaine, Dextromethorphan, Dolasetron, Benzphetamine, Amoxapine, Escitalopram, Lisdexamfetamine etc.

Phentermine Medicine

There are 194 medicinal drugs that can interacts with Phentermine medicine. These drugs include Desvenlafaxine, Dexmethylphenidate, Diethylpropion, Esketamine, Glimepiride, Albiglutide, Benzphetamine, Buspirone, Eletriptan and so on.

Side Effects: Belviq vs Phentermine

Belviq Medicine

The side effects of Belviq medicine are as follows:

  • Sore throat
  • Fast or irregular heartbeat
  • Sneezing
  • Dryness in mouth or skin
  • Joint pain
  • Numbness or tingling in hands and feet
  • Swelling in hands, arms, face or lower legs
  • Seizures (convulsions)
  • Sweating
  • Shivering
  • Muscle spasms
  • Back pain
  • Diarrhea
  • Sneezing
  • Agitation (severe anxiety)
  • Headache
  • Dizziness, light-headedness or fainting

Phentermine Medicine

Phentermine medicine causes different side effects in individuals. These include the following:

  • Breathing problems
  • Bad or unpleasant taste
  • Skin rashes, itching or hives
  • Chest pain or tightness in chest
  • Heart palpitations
  • Sleeping problems (Insomnia)
  • Fatigue
  • Hallucinations
  • Euphoria
  • Dysphoria
  • Cardiac arrest
  • Tachycardia
  • Precordial pain
  • Psychosis
  • Erectile Dysfunction (Impotence)
  • Constipation
  • Angina
  • Mood or behavioural change

Precautions for Phentermine vs Belviq Drug:

  • An individual must avoid taking more than one tablet of Belviq or Phentermine medicine. Taking overdose of this medicine can be dangerous for him or her.
  • An individual should not consume alcohol or smoke cigarettes after taking any of these medication drugs. This can cause dizziness or drowsiness which can be dangerous for a person.
  • This medication drug must be swallowed with a glass of water to avoid its bitter taste.
  • Taking Belviq or Phentermine medicine is strictly prohibited if an individual is taking other nitrate drugs for the treatment of obesity.
  • An individual should not drive a car or perform any other activities after taking any of these medication drugs. These medicines can cause drowsiness which become dangerous for him or her.
  • People must consult with a doctor before taking Belviq or Phentermine medicine.


In conclusion, phentermine and Belviq medicines are used in the treatment of obesity condition. Both are almost similar, but there are differences depending on some factors. These drugs act in the central nervous system and helps to reduce appetite of an individual. To avoid misuse and abuse it is better to get your tablets with a proper doctor’s prescription and take them with a healthy lifestyle routine.

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