Phentermine (Adipex-P) Weight Loss Drug Side Effects & Dosage

What is phentermine?

Phentermine is a drug that suppresses appetite.

Why is phentermine prescribed to patients?

• Phentermine is combined with
  diet and
  exercise for the
  short-term treatment of
  obesity in individuals with a body mass index greater
  than or equal to 30 kg/m2 or greater than or equal to 27 kg/m2 with risk factors
  for heart disease.
• Phentermine should not be combined with other
  weight loss
  agents.
• The combination of phentermine and fenfluramine (FEN-PHEN) is associated
  with serious heart problems. Fenfluramine is no longer available in the United
  States.

Is phentermine available as a generic drug?

Yes

Do I need a prescription for phentermine?

Yes.
It is a schedule IV controlled substance.

What brand names are available for phentermine?

• Brand available in the US for phentermine are Adipex-P and Lomaira.
• Discontinued brands are Fastin, Oby-Trim, Obestin-30, OnaMast, Tora, Obenix, Suprenza, and Wilpo.

What are the side effects of phentermine?

Side effects of phentermine include:

• nausea,
• vomiting,
• diarrhea,
• dry mouth,
• constipation,
• an unpleasant taste,
• hives,
• impotence,
• palpitations,
• high blood pressure, and
• fast heart rates (palpitations).

Central nervous system
side effects include:

• hyperactivity,
• insomnia,
• restlessness,
• tremor, and
• dizziness.

Phentermine, especially when combined with fenfluramine, has been
associated with high pressures in the pulmonary arteries (pulmonary hypertension) and defects in heart valves, both serious complications.

Physical
and psychological dependence may occur with the long-term use of phentermine. A
withdrawal reaction, which includes excessive drowsiness, fatigue, tremors and
depression may occur after prolonged use.

What is the dosage for phentermine?

• The recommended dose is 15-37.5 mg once daily.
• Adipex-P is
  administered about 1-2 hours after breakfast.
• The lowest effective dose should
  be used and evening doses should be avoided because phentermine causes
  insomnia.

Which drugs or supplements interact with phentermine?

• Phentermine is similar to amphetamine and may share some
  of the interactions associated with amphetamines. Combining phentermine with
  tricyclic antidepressants (for example,
  amitriptyline [Elavil, Endep]) or
  monoamine oxidase inhibitors
  or MAOIs (for example, phenelzine [Nardil],
  selegiline [Zelapar, Emsam, and Eldepryl], tranylcypromine
  [Parnate]) may result in
  high blood pressure and other serious
  reactions because of elevated serotonin levels in the blood. Phentermine should
  not be used within 14 days after stopping a monoamine oxidase inhibitor.
• People with
  diabetes being treated with phentermine may require a
  reduction in their dose of insulin or oral hypoglycemic drug.
• Combining alcohol with phentermine may result in an adverse drug
  reaction.

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Is phentermine safe to use during pregnancy or while breastfeeding?

• Use of phentermine
  during
  pregnancy has not been adequately
  evaluated.
• It is not known whether phentermine is excreted in human
  breast milk. Since other amphetamines are excreted in breast milk, phentermine
  should not be used while
  breastfeeding or, if used,
  nursing should be
  discontinued.

What else should I know about phentermine?

What preparations of phentermine are available?

• Tablets: 8 and 37.5 mg.
• Capsules: 15, 30,
  37.5 mg.

How should I keep phentermine stored?

Phentermine should be stored in a tight container at room
temperature, 20 C to 25 C (68 F to 77 F).

How does phentermine work?

• The exact mechanism of action of phentermine is unknown. It probably decreases appetite by acting
  on centers in the brain that control appetite. Phentermine is similar to amphetamine. It stimulates the nervous system, elevates
  blood pressure, and
  increases heart rate.