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Main menu: Drug interactions

This Menu contains links to pages related to DRUG INTERACTIONS. Other MAIN MENUS can be found by hovering over the MAIN MENUS tab at the top of every page on this website.


In the Menu below, click on the category (or the arrow to the left of its name) to EXPAND the category and see what is included in it.

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Drug interaction search (checker) tools

Drug interaction search (checker) tools: Free options

Drug interaction search (checker) tools: Paid options

Levels of seriousness in drug interaction search results

Video: How to do efficient drug interaction searches to quickly identify the important ones

Clinical example: Why we should ALWAYS do a quick drug interaction search 

Who’s job is it to check for drug interactions?

COVID-19 drug interaction checker

How to check for drug interactions with an herbal product like ashwagandha

How to easily search for drug interactions with cannabidiol

Cytochrome P450 interactions

Cytochrome P450 system and psychiatric medications: An introduction and important tips

Cytochrome P450 3A4: Substrates, inhibitors, and inducers

What the FDA’s “Table of Pharmacogenetic Associations” says about psychotropic medications

Pharmacogenetic testing in the office: Cytochrome P450 enzymes

The  Flockhart P450 Drug Interaction Table: Full table (Link to external site)

Supplement to Flockhart table

Antidepressants with much fewer P450 drug interactions

Doxepin and cytochrome P450 drug interactions

One exit door or many?

Cytochrome P450 drug interactions with benzodiazepines

Drug interactions with ADHD medications

Important interactions when using two medications for ADHD

Vitamin C if on a stimulant?

Be careful if a person is on both a stimulant and an antipsychotic

What could happen when changing from an antipsychotic to a stimulant?

Can a dopamine agonist (pramipexole, ropinirole) and a stimulant be combined?

Ketogenic diet and amphetamines

When prescribing an amphetamine, warn patients about anti-acid medications

Order genetic testing for a patient on atomoxetine?

Seizure risk if atomoxetine and bupropion are used together?

Drug interactions with antidepressant medications

Antidepressants with much fewer P450 drug interactions

Doxepin and cytochrome P450 drug interactions

Drug interactions with antipsychotic medications

What could happen when changing from an antipsychotic to a stimulant?

Be careful if a person is on both a stimulant and an antipsychotic

Drug interactions with COVID-19 medications

COVID-19 drug interaction checker

Nirmatrelvir-ritonavir (Paxlovid™): Drug interactions with psychiatric medications

Can patients on lurasidone take nirmatrelvir + ritonavir (Paxlovid®)? 

Drug interactions with caffeine

Caffeine can significantly change serum clozapine levels

Interactions that can significantly affect caffeine metabolism

Drug interactions with cannabinoids

Effects of cannabis or cannabinoids on the cytochrome P450 enzymes

Drug interactions with cardiovascular medications

Lithium and antihypertensives: Be careful!

Direct-acting oral anticoagulants (DOACs) and antidepressants

Very important drug interactions between warfarin and psychotropic medications

Drug interactions with food and beverages

Grapefruit or its juice can interact with psychotropic medications

Ketogenic diet and amphetamines

Ketogenic diet and topiramate

Ketogenic diet and valproate

Vitamin C if on a stimulant?

Drug interactions with herbs and supplements

Interactions between herbal and psychotropic medications

What drug interactions can occur with melatonin?

Biotin can interfere with many laboratory tests—and lead to serious misdiagnosis

How to check for drug interactions with an herbal product like ashwagandha

Drug interactions with lithium

Lithium and antihypertensives: Be careful!

Drug interactions with monoamine oxidase inhibitors (MAOIs)

MAO inhibitors and other medications

MAO Inhibitors and other medications (patient handout) (link to the handouts page)

Be very careful when switching from one MAO inhibitor to another

MAO inhibitors (MAOIs) and contraindicated medications: How long do we have to wait?

How to switch from oral or transdermal selegiline (Emsam®) to another MAO inhibitor

Should we prescribe emergency medication for hypertensive urgency with MAO inhibitors?

“Treatment-resistant” depression: Can a classic MAO inhibitor be safely augmented with an antipsychotic?

Drug interactions with oral contraceptives and intrauterine devices

5 Action Items about OCs and lamotrigine

Does lamotrigine decrease the effectiveness of oral contraceptives?

Change lamotrigine dose in transgender women starting hormonal therapy?

Can oral contraceptives affect clozapine levels?

Don’t cause unwanted pregnancy

Do psychotropic medications affect intrauterine devices (IUDs)?

Drug interactions with tobacco smoking

Smoking can seriously affect some psychotropic medications

Time course of decrease in CYP1A2 activity after smoking cessation

Drug interactions: Miscellaneous

Common and important drug Interactions in psychopharmacology

Think twice before adding topiramate to valproate

Some antidepressants may have clinically important interactions with tramadol (Ultram®)

Important instructions regarding MAO inhibitors and other medications

Why is dextromethorphan being combined with a CYP 2D6 inhibitor?

Switching antidepressants: A difficult case

Important drug interactions between antiretrovirals and antidepressants

Dose adjustment for second-generation antipsychotics based on drug interactions

Drug interactions affecting prodrugs

Tamsulosin (Flomax®) and psychiatric medications: What to watch for


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Disclaimer: The content on this website is provided as general education for medical professionals. It is not intended or recommended for patients or other laypersons or as a substitute for medical advice, diagnosis, or treatment. Patients must always consult a qualified healthcare professional regarding their diagnosis and treatment. Healthcare professionals should always check this website for the most recently updated information.

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