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Psychiatric Drug-Drug Interactions
Medscape Psychiatry & Mental Health
US Pharmacist. 2012;37(11):HS-16-HS-19.

Note: This is a technical article generally intended for reference to medical professionals. Forum members may find insights into frequent concerns about drug interactions among the medications commonly used in treating mental health disorders. Complete :acrobat: article is attached to this post and can be downloaded /printed for future reference.

The vast increase in the number of new psychopharmacologic agents has made more therapeutic options available,
but it has also complicated patient treatment. Combination therapy used in psychiatric practice makes drug
interactions more likely and increases the risk of adverse outcomes to patients. The amount of information on drugdrug
interactions is overwhelming, so health systems have implemented the use of computer software to assist in the
detection of these problematic combinations. While these systems offer necessary support, the pharmacist's
expertise in triaging these alerts and communicating the relevance to the prescriber is essential. This review will
provide an essential refresher on psychiatric drug interactions for institutional practitioners as well as offering
suggestions to optimize patient safety when patients are on medication regimens that include psychiatric drugs.

The vast increase in the number of new psychopharmacologic agents over the last 20 years has made more
therapeutic options available, but it also has made treating patients more complicated. Prescribing practices, which
include the concurrent administration of a variety of psychotropic drugs, have made the risk of drug-drug interactions
more likely. Drug interactions are known to play a significant role in the incidence of adverse drug reactions (ADRs)
both in the community and in hospitals. Reducing ADRs is a critical element in providing safe medication use for
hospitalized patients. According to a recently published study, psychiatric medications can account for up to 50% of
the ADRs for hospitalized patients with mental illness, many of which can be attributed to drug-drug interactions.1
ADRs resulting from drug-drug interactions leading to hospitalization are often preventable. It has been estimated that
26% of ADRs requiring hospital admissions may be due to drug-drug interactions.2

Even ADRs that are deemed to be "not severe" can have significant impact on patients with a psychiatric illness, as a
growing body of evidence suggests a strong relationship between drug-drug interactions, treatment failures, and
higher health care costs due to avoidable medical complications.3 While only a few of the possible drug interactions
may be clinically relevant, the practitioner still must consider critical factors associated with drug-drug interactions.
Such factors include the potency and concentration of the drugs involved, the therapeutic index balanced between
efficacy and toxicity, the presence of active metabolites, and the extent of the metabolism of the substrate drug.4

*References in attached complete article


  • Psychiatric Drug Drug Interactions.pdf
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Thanks for sharing this article. I have most of my past medical files and I've been checking out the drug interactions. Unfortunately I was setting off red flags, complete with the warning sign symptoms, all over the place.

A pharmacist told me about these 2 links:
Multi-Drug Interaction Checker: Medscape: Medscape Access


Drug Interactions Checker: Drug Interactions

and boy, were they helpful.

The main things I ran into with drug conflicts were serotonin syndrome, tardive dyskonesia, tardive akathasia, and tardive dystonia. I also had brain wave irregularities on the EEG and heart beat irregularities on the EKG (T-Waves).

Now that I'm off all medications and out of the mental health system, my doctor has decided to do a comparative EEG. It would be interesting to find out if the EEG results classified as dysrhythmia, grade 1, generalized is gone.

We're not exactly sure what that means yet, but on reading through my medical files my doctor noticed I didn't have it prior to 1983. When I developed it, behaviourly I was having a really hard time.

Our hope is that if my results come back negative for this now, then the facts can be used to educate others on the effects of medications.
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