How should I take phentermine?
Take phentermine exactly as directed by your doctor.
If you do not understand these directions, ask your pharmacist,
nurse, or doctor to explain them to you.
Take each dose with a full glass of water.
Phentermine is usually taken once or twice a day
before a meal on an empty stomach.
Do not take phentermine in the evening because it
may cause insomnia.
Do not crush, chew or open any "once-daily"
phentermine tablets or capsules. Swallow them whole.
Never take more of this medication than is prescribed
for you. Too much phentermine could be very dangerous to
Store phentermine at room temperature away from moisture
What happens if I miss a dose?
Take the missed dose as soon as you remember. However,
if it is almost time for your next dose or if it is already
evening, skip the missed dose and take only your next regularly
scheduled dose. A dose taken too late in the day will cause
insomnia. Do not take a double dose of this medication.
What happens if I overdose?
Seek emergency medical attention.
Symptoms of a phentermine overdose include restlessness,
tremor, rapid breathing, confusion, hallucinations, panic,
aggressiveness, nausea, vomiting, dia
What should I avoid while taking phentermine?
rrhea, an irregular heartbeat, and seizures.
Use caution when driving, operating machinery, or
performing other hazardous activities. Amphetamine may cause
dizziness, blurred vision, or restlessness, and it may hide
the symptoms of extreme tiredness. If you experience these
effects, avoid hazardous activities.
Do not take phentermine late in the day. A dose taken
too late in the day can cause insomnia.
What are the possible side effects of phentermine?
If you experience any of the following serious side
effects, stop taking phentermine and seek emergency medical
· an allergic reaction (difficulty breathing; closing
of your throat; swelling of your lips, tongue, or face;
· an irregular heartbeat or very high blood pressure
(severe headache, blurred vision); or
· hallucinations, abnormal behavior, or confusion.
Other, less serious side effects may be more likely
to occur. Continue to take phentermine and talk to your
doctor if you experience
· restlessness or tremor,
· nervousness or anxiety,
· headache or dizziness,
· dry mouth or an unpleasant taste in your mouth,
· diarrhea or constipation, or
· impotence or changes in your sex drive.
Phentermine is habit forming. You can become physically
and psychologically dependent on this medication, and withdrawal
effects may occur if you stop taking it suddenly after several
weeks of continuous use. Talk to your doctor about stopping
this medication gradually.
Side effects other than those listed here may also
occur. Talk to your doctor about any side effect that seems
unusual or that is especially bothersome.
What other drugs will affect phentermine?
You cannot take phentermine if you have taken a monoamine
oxidase inhibitor (MAOI) such as isocarboxazid (Marplan),
tranylcypromine (Parnate), or phenelzine (Nardil) in the
last 14 days.
Changes in insulin and other diabetes drug therapies
may be necessary during treatment with phentermine.
Phentermine may reduce the effects of guanethidine
(Ismelin). This could lead to an increase in blood pressure.
Tell your doctor if you are taking guanethidine.
Before taking this medication, tell your doctor if
you are taking a tricyclic antidepressant such as amitriptyline
(Elavil), amoxapine (Asendin), doxepin (Sinequan), nortriptyline
(Pamelor), imipramine (Tofranil), clomipramine (Anafranil),
protriptyline (Vivactil), or desipramine (Norpramin). These
drugs may decrease the effects of phentermine.
Drugs other than those listed here may also interact
with phentermine. Talk to your doctor and pharmacist before
taking any prescription or over-the-counter medicines.
Where can I get more information?
Your pharmacist has more information about phentermine
written for health professionals that you may read.