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.