Is it safe to take Phentermine and Fluoxetine at the same time?

[ggglitch]

I have a friend who was prescribed both at the same time, she seems to have no side effects and it's working great for her.
I also have another friend who said her doctor said it is not safe to take both at the same time.

Has anyone tried both? I'm currently on Prozac and happy with it but am interested in taking Phentermine as well.


Thanks

[QVC1212]

No, you must not take the two concurrently!! You could develop serotonin syndrome and die from it. Here is what Medscape's drug interaction checker has to say:

Phentermine/SSRI's; Milnacipran

This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.

MONOGRAPH TITLE: Phentermine/SSRI's; Milnacipran

SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction.

MECHANISM OF ACTION: The exact mechanism is unknown, but may involve additive effects on serotonin.

CLINICAL EFFECTS: Concurrent administration of phentermine with a selective serotonin reuptake inhibitor or milnacipran may result in serotonin syndrome. Symptoms of serotonin syndrome may include irritability, altered consciousness, double vision, nausea, confusion, anxiety, hyperthermia, increased muscle tone, rigidity, myoclonus, rapid fluctuations in vital signs, and coma. Serotonin syndrome may result in death.

PREDISPOSING FACTORS: None determined.

PATIENT MANAGEMENT: The manufacturers of phentermine state that the concurrent use of phentermine with selective serotonin reuptake inhibitors is not recommended.(1,2)

DISCUSSION: In a case report, a 22 year-old female had previously been taking phentermine and oral contraceptive agents. The patient stopped taking phentermine and, after an undetermined length of time, started taking fluoxetine (20 mg daily). The patient discontinued her fluoxetine after three months. Eight days later, she took one dose of phentermine (30 mg). Within several hours, she developed jitteriness, stomach cramps, dry eyes, palpitations, and tremors. The patient received once dose of lorazepam (1.5 mg) and her symptoms resolved over night.(3) The manufacturers of phentermine state that the concurrent administration of phentermine and selective serotonin reuptake inhibitors is not recommended.(1,2)

[paperboy]

Now I am curious about how phentermine works!! I would have guessed dopamine,but not serotonin so much....

Although the example you gave, QVC, didn't exactly strike terror into my heart...she got tremors and ativan made them go away? she didn't even die??

[QVC1212]

I had a bad experience where the doctors suspected serotonin syndrome but went with a more basic diagnosis of "encephalopathy". It was not pleasant. They stopped all medications and the symptoms of tremors, hyperthermia, agitation and altered mental status resolved within a day. It may not strike terror into your heart (LOL) but it should at least give you pause.

Phentermine works to suppress hunger by releasing norepinephrine in the hypothalamus and, to a lesser extent, serotonin and dopamine.