Fluoxetine

Also indexed as: Prozac®

Fluoxetine is a member of the selective serotonin reuptake inhibitor (SSRI) family of drugs. Fluoxetine is used to treat depression, bulimia (binge-eating and vomiting), obsessive-compulsive disorder, and others conditions.

Summary of Interactions with Vitamins, Herbs, and Foods
(for details about the summarized interactions, read the full article)

Beneficial May be Beneficial: Depletion or interference—The medication may deplete or interfere with the absorption or function of the nutrient. Taking these nutrients may help replenish them.

Melatonin*
Beneficial May be Beneficial: Side effect reduction/prevention—Taking these supplements may help reduce the likelihood and/or severity of a potential side effect caused by the medication.

Ginkgo biloba
Beneficial May be Beneficial: Supportive interaction—Taking these supplements may support or otherwise help your medication work better.

DHEA*

Folic acid*
Avoid Avoid: Adverse interaction—Avoid these supplements when taking this medication because taking them together may cause undesirable or dangerous results.

5-HTP

Alcohol

L-tryptophan

St. John’s wort
Check Check: Other—Before taking any of these supplements or eating any of these foods with your medication, read this article in full for details.

Melatonin
Reduced drug absorption/bioavailability

None known

An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.

Interactions with Dietary Supplements

Folic acid
Low blood levels of folic acid have been correlated to poor response to fluoxetine.1 Furthermore, the addition of folic acid to fluoxetine appears to enhance the effectiveness of the drug. A double-blind trial found that depressed women receiving 500 mcg of folic acid per day in addition to fluoxetine experienced significant improvement in their symptoms, as well as fewer side effects, compared with women receiving only fluoxetine.2 Similar results were not observed in men; however, men appear to have a higher requirement for folic acid than do women, so a higher intake may be necessary.

Melatonin
Administration of fluoxetine for six weeks significantly lowered melatonin levels in people with seasonal affective disorder (SAD) and in healthy persons as well.3 Further study is needed to determine if this might interfere with sleeping or whether melatonin supplementation might be appropriate.

L-tryptophan
L-tryptophan is an amino acid found in protein-rich foods. Foods rich in L-tryptophan are not believed to cause any problems during fluoxetine use. However, dietary supplements of L-tryptophan taken during fluoxetine treatment have been reported to cause headache, sweating, dizziness, agitation, restlessness, nausea, vomiting, and other symptoms.4

5-Hydroxytryptophan (5-HTP)
Fluoxetine works by increasing serotonin activity in the brain. 5-HTP is converted to serotonin in the brain, and taking it with fluoxetine may increase fluoxetine-induced side effects. Until more is known, 5-HTP should not be taken with any SSRI drug, including fluoxetine.

DHEA
DHEA supplementation (50 mg per day) has been shown to restore the response of beta-endorphin, a brain chemical involved in pain and pleasure sensations, to fluoxetine.5 Further research is needed to determine if this drug combination is safe for long-term use.

Interactions with Herbs

Ginkgo biloba
Ginkgo biloba extract (GBE) may reduce the side effects experienced by some persons taking SSRIs such as fluoxetine or sertraline. An open-label study with elderly, depressed persons found that 200–240 mg of GBE daily was effective in alleviating sexual side effects in both men and women taking SSRIs.6 One case study reported that 180–240 mg of GBE daily reduced genital anesthesia and sexual side effects secondary to fluoxetine use in a 37-year-old woman.7

St. John’s wort (Hypericum perforatum)
There have been no published reports about negative consequences of combining St. John’s wort and fluoxetine. One case has been reported of an interaction between St. John’s wort and a weak serotonin reuptake inhibitor drug known as trazodone that is vaguely similar to fluoxetine.8 In another case, a patient experienced grogginess, lethargy, nausea, weakness, and fatigue after taking one dose of paroxetine (Paxil®, another SSRI drug) after ten days of St. John’s wort use.9 Nevertheless, some doctors are concerned about the possibility of an interaction between St. John’s wort and fluoxetine causing side effects (e.g., mental confusion, muscle twitching, sweating, flushing) known collectively as serotonin syndrome.10 11 Until more is known about interactions and adverse actions, people taking any SSRI drugs, including fluoxetine, should avoid St. John’s wort, unless they are being closely monitored by a doctor.

Interactions with Foods and Other Compounds

Food
Fluoxetine may be taken with or without food.12

Alcohol
SSRI drugs, including fluoxetine, may cause dizziness or drowsiness.13 Alcohol may intensify these actions and increase the risk of accidental injury. Alcohol should be avoided during fluoxetine therapy. Fluoxetine has been reported to decrease the desire to drink alcohol in a group of alcoholics.14

References

1. Fava M, Borus JS, Alpert JE, et al. Folate, vitamin B12, and homocysteine in major depressive disorder. Am J Psychiatry 1997;154:426–8.

2. Coppen A, Bailey J. Enhancement of the antidepressant action of fluoxetine by folic acid: a randomised, placebo controlled trial. J Affect Disord 2000 Nov;60(2):121–30.

3. Childs PA, Rodin I, Martin NJ, et al. Effect of fluoxetine on melatonin in patients with seasonal affective disorder and matched controls. Br J Psychiatry 1995;166:196–8.

4. Threlkeld DS, ed. Central Nervous System Drugs, Antidepressants, Selective Serotonin Reuptake Inhibitors. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, Apr 1997, 264r–4s.

5. Stomati M, Rubino S, Spinetti A, et al. Endocrine, neuroendocrine and behavioral effects of oral dehydroepiandrosterone sulfate supplementation in postmenopausal women. Gynecol Endocrinol 1999;13:15–25.

6. Cohen AJ, Bartlik B. Ginkgo biloba for antidepressant-induced sexual dysfunction. J Sex Marital Ther 1998;24:139–45.

7. Ellison JM, DeLuca P. Fluoxetine-induced genital anesthesia relieved by Ginkgo biloba extract. J Clin Psychiatry 1998;59:199–200.

8. Demott K. St. John’s wort tied to serotonin syndrome. Clinical Psychiatry News 1998;26:28.

9. Gordon JB. SSRIs and St. John’s wort: possible toxicity? Am Fam Physician 1998;57:950.

10. Bekman SE, Sommi RW, Switzer J. Consumer sue of St. John’s wort: A survey on effectiveness, safety, and tolerability. Pharmacotherapy 2000;20:568–74.

11. Lantz MS, Buchalter E, Giambanco V. St. John’s wort and antidepressant drug interaction in the elderly. J Geriatr Psychiatry Neurol 1999;12:7–10.

12. Threlkeld DS, ed. Central Nervous System Drugs, Antidepressants, Selective Serotonin Reuptake Inhibitors. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparison, Apr 1997, 264r–4s.

13. Threlkeld DS, ed. Central Nervous System Drugs, Antidepressants, Selective Serotonin Reuptake Inhibitors. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparison, Apr 1997, 264r–4s.

14. Naranjo CA, Pouos CX, Bremner KE, Lanctot KL. Fluoxetine attenuates alcohol intake and desire to drink. Int Clin Psychopharmacol 1994;9:163–72.