If you are currently being treated with any of the following medications, you should not use 5-HTP without first talking to your healthcare provider.

Antidepressant Medications

Individuals taking the antidepressant medications known as selective serotonin reuptake inhibitors (SSRIs) (such as fluoxetine, paroxetine, sertraline, and citalopram) and monoamine oxidase inhibitors (MAOIs) (such as phenelzine, isocarboxazid, selegiline, and tranylcypromine) should not use 5-HTP as these medications enhance the action of these drugs and may increase the risk for developing a dangerous condition known as "serotonin syndrome." Serotonin syndrome is characterized by mental status changes, rigidity, hot flashes, rapidly fluctuating blood pressure and heart rate, and possibly coma. Similarly, other drugs for depression that interfere with the uptake of the neurotransmitter serotonin, namely trazodone and venlafexine, may also lead to serotonin syndrome when used along with 5-HTP.

Carbidopa

Taking 5-HTP with carbidopa, a medication used to treat Parkinson's disease, has been associated with side effects including scleroderma-like illnesses (a condition in which the skin becomes hard, thick, and inflamed).

Sumatriptan
Similar to antidepressants, sumatriptan, a medication used for migraine headaches that works by stimulating serotonin receptors in the brain, should also not be used in combination with 5-HTP because of the risk for serotonin syndrome.

Tramadol

Tramadol, used for pain control, may also increase serotonin levels too much if taken in combination with 5-HTP. Serotoninsyndrome has been reported in some people taking the two together.

Zolpidem

Use of zolpidem, a medication for insomnia, can cause hallucinations when used with SSRI antidepressants. Because 5-HTP may work similarly to SSRIs, the combination of 5-HTP with zolpidem could, theoretically, lead to hallucinations as well.