Risperidone with Ritonavir Interaction Details
Brand Names Associated with Risperidone
- Risperdal® M-TAB® Orally Disintegrating Tablets
- Risperdal® Oral Solution
- Risperdal® Tablets
- Risperidone
Brand Names Associated with Ritonavir
- Norvir®
- Ritonavir
- RTV
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 08, 2023
Interaction Effect
Increased risperiDONE serum concentrations and potential toxicity (hypotension, sedation, extrapyramidal effects, arrhythmias)
Interaction Summary
Coadministered ritonavir may increase serum concentrations of risperiDONE, resulting in risperiDONE toxicityA risperdal dose decrease may be required when coadministered with ritonavir .
Severity
Moderate
Onset
Rapid
Evidence
Probable
How To Manage Interaction
Monitor patients for signs and symptoms of neuroleptic toxicity (hypotension, sedation, extrapyramidal effects, arrhythmias). Reduce doses of risperiDONE as required.
Mechanism Of Interaction
Decreased risperiDONE metabolism
Literature Reports
A) Increases in risperiDONE serum concentration occurred in a patient taking concomitant ritonavir. A 48-year-old man previously diagnosed with acquired immunodeficiency syndrome (AIDS) was admitted to a psychiatric hospital for manic symptoms. His current medications included zidovudine 250 mg twice daily, didanosine 300 mg once daily, indinavir 400 mg twice daily, and ritonavir 200 mg twice daily. He was given risperiDONE 3 mg twice daily upon admission. After receiving two doses of risperiDONE he became ataxic, progressively drowsy and disoriented. He then became lethargic and comatose. Physical exam revealed a Glasgow coma score of 7/15 points with miotic pupils. Laboratory tests were normal. A toxic or metabolic etiology was suspected to be the cause of the coma and all medication was discontinued. Twenty-four hours later, his neurologic status returned to baseline and progressively the manic symptoms reappeared. The author suggests that an interaction between risperiDONE, indinavir and ritonavir may have caused a reversible toxic coma .
B) Extrapyramidal symptoms (EPS) occurred in a patient initiated on ritonavir and indinavir while taking risperiDONE for a tic disorder. A 35-year-old white male with AIDS received risperiDONE 2 mg twice daily for treatment of Tourette's-like tic disorder. The patient had an 8 month history of hand tremor, twitching and jerky involuntary movements of the face, shoulders, arms, and legs. His current medications were dapsone, pyrimethamine, azithromycin, and hydroxyzine. RisperiDONE was initiated at 1 mg twice daily for 2 weeks and then increased to 2 mg twice daily. Indinavir 800 mg twice daily and ritonavir 200 mg twice daily was initiated at the same time the risperiDONE dosage was increased. One week later he experienced significantly impaired swallowing, speaking, and breathing, and worsening of his existing tremors. Ritonavir and indinavir were discontinued. One month later the patient agreed to try indinavir/ritonavir therapy again. At the same time he increased the risperiDONE dose to 3 mg twice daily. Symptoms worsened over the next 3 days. All laboratory parameters were unremarkable and vital signs were stable. RisperiDONE was discontinued and clonazepam initiated. Three days later the patients symptoms improved. Caution is warranted when risperiDONE is prescribed with ritonavir/indinavir .
Risperidone Overview
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Risperidone is used to treat the symptoms of schizophrenia (a mental illness that causes disturbed or unusual thinking, loss of interest in life, and strong or inappropriate emotions) in adults and teenagers 13 years of age and older. It is also used to treat episodes of mania (frenzied, abnormally excited, or irritated mood) or mixed episodes (symptoms of mania and depression that happen together) in adults and in teenagers and children 10 years of age and older with bipolar disorder (manic depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods). Risperidone is also used to treat behavior problems such as aggression, self-injury, and sudden mood changes in teenagers and children 5 to 16 years of age who have autism (a condition that causes repetitive behavior, difficulty interacting with others, and problems with communication). Risperidone is in a class of medications called atypical antipsychotics. It works by changing the activity of certain natural substances in the brain.
Ritonavir Overview
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Ritonavir is used along with other medications to treat human immunodeficiency virus (HIV) infection. Ritonavir is in a class of medications called protease inhibitors. It works by decreasing the amount of HIV in the blood. Although ritonavir 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.
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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.