In general..
Prozac interacts with tricyclic antidepressants.
In Useful Websites above on this forum are links to all kinds of references about drugs, including interactions.
Quote:
2 potential interactions were found for the drugs you selected.
You searched for interactions between the following drugs:
* Pamelor
* Prozac
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(Note: Not all drug interactions are known or reported in the literature, and new drug interactions are continually being reported. This information is provided only for your education and for you to discuss with your personal healthcare provider. )
FLUOXETINE (in Prozac) may interact with NORTRIPTYLINE (in Pamelor)
Both fluoxetine and nortriptyline have an effect on serotonin, a chemical that is found in the brain. Excess levels of serotonin in the brain may cause serious or potentially life-threatening side effects. Early signs of this problem include increased confusion and restlessness. Other possible symptoms may include weakness, fever, nausea, and anxiety. In rare cases, high levels of serotonin in the brain may cause severe complications like seizures, stroke, and even death. If these drugs are used together, your doctor may want to monitor you closely when therapy with fluoxetine is started or stopped. If you are experiencing problems, it may be necessary to adjust the dose of nortriptyline or to stop therapy with either drug. Discuss this potential interaction with your healthcare provider at your next appointment, or sooner if you think you are having problems.
This interaction is well-documented and is considered moderate in severity.
Last Updated: December 2003
FOOD may interact with NORTRIPTYLINE (in Pamelor)
Foods that have a high fiber content may interfere with the absorption of nortriptyline from the stomach. As a result, less nortriptyline would be available for the body to use and blood levels could become too low. This could make the drug less effective. High fiber foods include fruits, vegetables, and grains (bread, cereal, rice, and pasta). Let your doctor know if you have recently changed your diet to include more high fiber foods while you are taking nortriptyline. If the nortriptyline does not seem to be working properly, it may be helpful to adjust your diet. You may want to ask your healthcare provider about this potential interaction if you think you are having problems.
This interaction is poorly documented and is considered moderate in severity.
Last Updated: December 2003
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Prozac interferes with the metabolism of TCAs...
and most drug sites do not list that:
Quote:
1: Clin Pharmacol Ther. 1992 Mar;51(3):239-48. Links
Quantification and mechanism of the fluoxetine and tricyclic antidepressant interaction.
* Bergstrom RF,
* Peyton AL,
* Lemberger L.
Lilly Laboratory for Clinical Research, Eli Lilly and Company, Indianapolis, IN 46285.
Clinical reports of concurrent use of fluoxetine and tricyclic antidepressant agents suggest that tricyclic concentrations increase upon coadministration with fluoxetine. This study was conducted to confirm the clinical reports, to quantify the degree of change in tricyclic kinetics, and to establish the mechanism of interaction. Twelve male subjects were given 50 mg desipramine (six subjects) or 50 mg imipramine (six subjects) on three occasions: alone, after a 60 mg dose of fluoxetine, and after eight daily 60 mg doses of fluoxetine. Fluoxetine significantly reduced oral clearance of both imipramine and desipramine as much as tenfold and prolonged half-life as much as fourfold. Desipramine oral clearance values were 289, 112, and 27 L/hr alone, after a single fluoxetine dose, and after multiple fluoxetine doses, respectively. Correspondingly, imipramine oral clearance values were 181, 87, and 51 L/hr. These kinetic changes resulted in significantly higher plasma tricyclic concentrations after fluoxetine administration. The amount of parent drug excreted unchanged in urine increased and imipramine or desipramine clearance to their respective 2-hydroxy metabolites decreased. Metabolic conversion of imipramine to desipramine appeared to be unaffected. The findings indicate that fluoxetine causes an inhibition of tricyclic 2-hydroxylation and may decrease first-pass and systemic metabolism. When imipramine or desipramine are to be coadministered with fluoxetine, a lower dosage may be needed to maintain steady-state concentrations and to avoid undesirable side effects caused by excessive tricyclic concentrations.
PMID: 1544284 [PubMed - indexed for MEDLINE]
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This would be dose dependent. That is high dose Nortriptyline would be more problematic than say 10mg (high dose would be 50mg)
10mg could become 40mg physiologically and 50mg becomes 200mg. Elavil is also affected the same way.
When TCAs get really high they can affect the heart.
If you go to post #4 here-- there is more heart data with drug lists:
http://neurotalk.psychcentral.com/showthread.php?t=1120
Fluoxetine (Prozac) and nortriptyline are on list #3...
When 2 appear together, one has to be more careful.
http://www.torsades.org/medical-pros...ts/list-03.cfm |
