Citalopram with Saquinavir Interaction Details
Brand Names Associated with Citalopram
- Celexa®
- Citalopram
Brand Names Associated with Saquinavir
- Invirase®
- Saquinavir
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 11, 2023
Interaction Effect
An increased risk of QT interval prolongation
Interaction Summary
The concomitant use of citalopram and ritonavir-boosted saquinavir is not recommended due to additive effects on QT interval prolongation and an increased risk of serious cardiovascular effects, including ventricular arrhythmias. These drugs should be used concomitantly only when no alternatives are available and the potential benefits outweigh the potential risks. Do not initiate concomitant therapy in patients with a baseline QT interval of greater than 450 milliseconds. In patients with a baseline QT interval of less than 450 milliseconds, perform an on-treatment ECG approximately 3 to 4 days after therapy is initiated. During concomitant therapy, if a subsequent QT interval reading is greater than 480 milliseconds or has increased by more than 20 milliseconds from baseline, evaluate whether to discontinue either citalopram or ritonavir-boosted saquinavir or both . Saquinavir is also a CYP3A4 inhibitor and has the potential to increase citalopram exposure. If coadministration is required, monitor for ECG changes. Do not exceed citalopram doses of 40 mg/day and discontinue citalopram in patients who have persistent QTc measurements greater than 500 milliseconds .
Severity
Major
Onset
Unspecified
Evidence
Theoretical
How To Manage Interaction
The concomitant use of citalopram and ritonavir-boosted saquinavir is not recommended due to additive effects on QT interval prolongation and an increased risk of serious cardiovascular effects, including ventricular arrhythmias. These drugs should be used concomitantly only when no alternatives are available and the potential benefits outweigh the potential risks. Do not initiate concomitant therapy in patients with a baseline QT interval of greater than 450 milliseconds. In patients with a baseline QT interval of less than 450 milliseconds, perform an on-treatment ECG approximately 3 to 4 days after therapy is initiated. During concomitant therapy, if a subsequent QT interval reading is greater than 480 milliseconds or has increased by more than 20 milliseconds from baseline, evaluate whether to discontinue either citalopram or ritonavir-boosted saquinavir or both . If coadministration is required, monitor for ECG changes. Do not exceed citalopram doses of 40 mg/day, and discontinue citalopram in patients who have persistent QTc measurements greater than 500 milliseconds .
Mechanism Of Interaction
Inhibition of citalopram CYP3A4-mediated metabolism; additive effects on QT interval prolongation
Citalopram Overview
-
Citalopram is used to treat depression. Citalopram is in a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs). It works by increasing the amount of serotonin, a natural substance in the brain that helps maintain mental balance.
Saquinavir Overview
-
Saquinavir is used in combination with ritonavir (Norvir) and other medications to treat human immunodeficiency virus (HIV) infection. Saquinavir is in a class of medications called protease inhibitors. It works by decreasing the amount of HIV in the blood. Although saquinavir does not cure HIV, it may decrease your chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as serious infections or cancer. Taking these medications along with practicing safer sex and making other lifestyle changes may decrease the risk of transmitting the HIV virus to other people.
Return To Our Drug Interaction Homepage
Feedback, Question Or Comment About This Information?
Ask Dr. Brian Staiger, PharmD, our medical editor, directly! He's always more than happy to assist.
Definitions
Severity Categories
Contraindicated
These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.
Major
This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.
Moderate
This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.
Minor
While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.
Onset
Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.
Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.
Evidence
Level of documentation of the interaction.
Established: The interaction is documented and substantiated in peer-reviewed medical literature.
Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.
How To Manage The Interaction
Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.
It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.
Mechanism Of Interaction
The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.
Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.
Where Does Our Information Come From?
Information for our drug interactions is compiled from several drug compendia, including:
The prescribing information for each drug, as published on DailyMED, is also used.
Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.
The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.