Ritonavir
Looking up MedlinePlus…
From MedlinePlus, U.S. National Library of Medicine
Boxed warning
WARNING: DRUG-DRUG INTERACTIONS LEADING TO POTENTIALLY SERIOUS AND/OR LIFE THREATENING REACTIONS Co-administration of ritonavir with several classes of drugs including sedative hypnotics, antiarrhythmics, or ergot alkaloid preparations may result in potentially serious and/or life-threatening adverse events due to possible effects of ritonavir on the hepatic metabolism of certain drugs. Review medications taken by patients prior to prescribing ritonavir or when prescribing other medications to patients already taking ritonavir.
[see Contraindications 4 , Warnings and Precautions 5.1 ] WARNING: DRUG-DRUG INTERACTIONS LEADING TO POTENTIALLY SERIOUS AND/OR LIFE THREATENING REACTIONS See full prescribing information for complete boxed warning Co-administration of ritonavir with several classes of drugs including sedative hypnotics, antiarrhythmics, or ergot alkaloid preparations may result in potentially serious and/or life-threatening adverse events due to possible effects of ritonavir on the hepatic metabolism of certain drugs. Review medications taken by patients prior to prescribing ritonavir or when prescribing other medications to patients already taking ritonavir. ( 4 , 5.1 ) .
Cytochrome P450 3A Inhibitor, Protease Inhibitor
Dosing in kidney impairment
Postmarketing life-threatening cases of cardiac toxicity (including complete AV block, bradycardia, and cardiomyopathy), lactic acidosis, acute renal failure, CNS depression and respiratory complications leading to death have been reported, predominantly in preterm neonates receiving lopinavir/ritonavir oral solution which also contains the excipients ethanol and propylene glycol.
Ritonavir oral solution should not be used in preterm neonates in the immediate postnatal period because of possible toxicities. However, if the benefit of using ritonavir oral solution to treat HIV infection in infants immediately after birth outweighs the potential risks, infants should be monitored closely for increases in serum osmolality and serum creatinine, and for toxicity related to ritonavir oral solution including: hyperosmolality, with or without lactic acidosis, renal toxicity, CNS depression (including stupor, coma, and apnea), seizures, hypotonia, cardiac arrhythmias and ECG changes, and hemolysis.
Dosing in liver impairment
Hepatic Impairment No dose adjustment of ritonavir is necessary for patients with either mild (Child-Pugh Class A) or moderate (Child-Pugh Class B) hepatic impairment. No pharmacokinetic or safety data are available regarding the use of ritonavir in subjects with severe hepatic impairment (Child-Pugh Class C), therefore, ritonavir is not recommended for use in patients with severe hepatic impairment [see Warnings and Precautions, Clinical Pharmacology] .
Preparation and administration
General Administration Recommendations Ritonavir must be used in combination with other antiretroviral agents. Ritonavir is administered orally. Ritonavir tablets should be swallowed whole, and not chewed, broken or crushed. Take ritonavir with meals. General Dosing Guidelines: Patients who take the 600 mg twice daily soft gel capsule ritonavir dose may experience more gastrointestinal side effects such as nausea, vomiting, abdominal pain or diarrhea when switching from the soft gel capsule to the tablet formulation because of greater maximum plasma concentration (Cmax) achieved with the tablet formulation relative to the soft gel capsule [see Clinical Pharmacology] .
Patients should also be aware that these adverse events (gastrointestinal or paresthesias) may diminish as therapy is continued.
| Body Surface Area (m2) | Twice Daily Dose 250 mg per m2 | Twice Daily Dose 300 mg per m2 | Twice Daily Dose 350 mg per m2 | Twice Daily Dose 400 mg per m2 |
| 0.20 | 0.6 mL (50 mg) | 0.75 mL (60 mg) | 0.9 mL (70 mg) | 1.0 mL (80 mg) |
| 0.25 | 0.8 mL (62.5 mg) | 0.9 mL (75 mg) | 1.1 mL (87.5 mg) | 1.25 mL (100 mg) |
| 0.50 | 1.6 mL (125 mg) | 1.9 mL (150 mg) | 2.2 mL (175 mg) | 2.5 mL (200 mg) |
| 0.75 | 2.3 mL (187.5 mg) | 2.8 mL (225 mg) | 3.3 mL (262.5 mg) | 3.75 mL (300 mg) |
| 1.00 | 3.1 mL (250 mg) | 3.75 mL (300 mg) | 4.4 mL (350 mg) | 5 mL (400 mg) |
| 1.25 | 3.9 mL (312.5 mg) | 4.7 mL (375 mg) | 5.5 mL (437.5 mg) | 6.25 mL (500 mg) |
| 1.50 | 4.7 mL (375 mg) | 5.6 mL (450 mg) | 6.6 mL (525 mg) | 7.5 mL (600 mg) |
Drug interactions
Check ritonavir against a medication listLabel text (17 paragraphs)
When co-administering ritonavir with other protease inhibitors (atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir), see the full prescribing information for that protease inhibitor including important information for drug interactions. Co-administration of ritonavir can alter the concentrations of other drugs. The potential for drug-drug interactions must be considered prior to and during therapy. ( 4 , 5.1 , 7 , 12.3 )
7.1 Potential for Ritonavir to Affect Other Drugs Ritonavir is an inhibitor of cytochrome P450 3A (CYP3A) and may increase plasma concentrations of agents that are primarily metabolized by CYP3A. Agents that are extensively metabolized by CYP3A and have high first pass metabolism appear to be the most susceptible to large increases in AUC (greater than 3-fold) when co-administered with ritonavir. Thus, co-administration of ritonavir with drugs highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening events is contraindicated.
Co-administration with other CYP3A substrates may require a dose adjustment or additional monitoring as shown in Table 4. Ritonavir also inhibits CYP2D6 to a lesser extent. Co-administration of substrates of CYP2D6 with ritonavir could result in increases (up to 2-fold) in the AUC of the other agent, possibly requiring a proportional dosage reduction. Ritonavir also appears to induce CYP3A, CYP1A2, CYP2C9, CYP2C19, and CYP2B6 as well as other enzymes, including glucuronosyl transferase. These examples are a guide and not considered a comprehensive list of all possible drugs that may interact with ritonavir.
The healthcare provider should consult appropriate references for comprehensive information.
7.2 Established and Other Potentially Significant Drug Interactions Table 4 provides a list of established or potentially clinically significant drug interactions. Alteration in dose or regimen may be recommended based on drug interaction studies or predicted interaction [see Contraindications ( 4 ), Warnings and Precautions ( 5.1 ), and Clinical Pharmacology ( 12.3 )] for magnitude of interaction. Table 4.
Established and Other Potentially Significant Drug Interactions Concomitant Drug Class: Drug Name Effect on Concentration of Ritonavir or Concomitant Drug Clinical Comment HIV-Antiviral Agents HIV-1 Protease Inhibitor: atazanavir darunavir fosamprenavir ↑ amprenavir ↑ atazanavir ↑ darunavir See the complete prescribing information for fosamprenavir, atazanavir, darunavir for details on co-administration with ritonavir. HIV-1 Protease Inhibitor: indinavir ↑ indinavir Appropriate doses for this combination, with respect to efficacy and safety, have not been established.
HIV-1 Protease Inhibitor: saquinavir ↑ saquinavir See the complete prescribing information for saquinavir for details on co-administration of saquinavir and ritonavir. Saquinavir/ritonavir in combination with rifampin is not recommended due to the risk of severe hepatotoxicity (presenting as increased hepatic transaminases) if the three drugs are given together. HIV-1 Protease Inhibitor: tipranavir ↑ tipranavir See the complete prescribing information for tipranavir for details on co-administration of tipranavir and ritonavir.
Non-Nucleoside Reverse Transcriptase Inhibitor: delavirdine ↑ ritonavir Appropriate doses of this combination with respect to safety and efficacy have not been established. HIV-1 CCR5-antagonist: maraviroc ↑ maraviroc See the complete prescribing information for maraviroc for details on co-administration of maraviroc and ritonavir-containing protease inhibitors. Integrase Inhibitor: raltegravir ↓ raltegravir The effects of ritonavir on raltegravir with ritonavir dosage regimens greater than 100 mg twice daily have not been evaluated, however raltegravir concentrations may be decreased with ritonavir co-administration.
Other Agents Alpha 1-Adrenoreceptor Antagonist: alfuzosin ↑ alfuzosin Contraindicated due to potential hypotension [see Contraindications ( 4 )]. Antianginal: ranolazine ↑ ranolazine Contraindicated due to potential for serious and/or life-threatening reactions [see Contraindications ( 4 )]. Analgesics, Narcotic: tramadol, propoxyphene, methadone, fentanyl ↑ analgesics ↓ methadone ↑ fentanyl A dose decrease may be needed for these drugs when co-administered with ritonavir. Dosage increase of methadone may be considered.
Careful monitoring of therapeutic and adverse effects (including potentially fatal respiratory depression) is recommended when fentanyl is concomitantly administered with ritonavir. Anesthetic: meperidine ↓ meperidine/ ↑ normeperidine (metabolite) Dosage increase and long-term use of meperidine with ritonavir are not recommended due to the increased concentrations of the metabolite normeperidine which has both analgesic activity and CNS stimulant activity (e.g., seizures).
Antialcoholics: disulfiram/ metronidazole Ritonavir formulations contain ethanol, which can produce disulfiram-like reactions when co-administered with disulfiram or other drugs that produce this reaction (e.g., metronidazole). Antiarrhythmics: amiodarone, dronedarone, flecainide, propafenone, quinidine ↑ antiarrhythmics Contraindicated due to potential for cardiac arrhythmias [see Contraindications ( 4 )]. Antiarrhythmics: disopyramide, lidocaine, mexiletine ↑ antiarrhythmics Caution is warranted and therapeutic concentration monitoring is recommended for antiarrhythmics when co-administered with ritonavir, if available.
Anticancer Agents: abemaciclib, apalutamide, dasatinib, encorafenib, ibrutinib, ivosidenib, neratinib, nilotinib, venetoclax, vinblastine, vincristine ↑ anticancer agents ↓ ritonavir # Apalutamide is contraindicated due to potential for loss of virologic response and possible resistance to ritonavir or to the class of protease inhibitors [see Contraindications ( 4 )]. Avoid co-administration of encorafenib or ivosidenib with ritonavir due to potential risk of serious adverse events such as QT interval prolongation. If co-administration of encorafenib with ritonavir cannot be avoided, modify dose as recommended in encorafenib USPI.
If co-administration of ivosidenib with ritonavir cannot be avoided, reduce ivosidenib dose to 250 mg once daily. Avoid use of neratinib, venetoclax or ibrutinib with ritonavir. For vincristine and vinblastine, consideration should be given to temporarily withholding the ritonavir containing antiretroviral regimen in patients who develop significant hematologic or gastrointestinal side effects when ritonavir is administered concurrently with vincristine or vinblastine.
Clinicians should be aware that if the ritonavir containing regimen is withheld for a prolonged period, consideration should be given to altering the regimen to not include a CYP3A or P-gp inhibitor in order to control HIV-1 viral load. A decrease in the dosage or an adjustment of the dosing interval of nilotinib and dasatinib may be necessary for patients requiring co-administration with strong CYP3A inhibitors such as ritonavir. Please refer to the nilotinib and dasatinib prescribing information for dosing instructions. Anticoagulant: warfarin ↑↓ warfarin Initial frequent monitoring of the INR during ritonavir and warfarin co-administration is recommended.
Anticoagulant: rivaroxaban ↑ rivaroxaban Avoid concomitant use of rivaroxaban and ritonavir. Co-administration of ritonavir and rivaroxaban may lead to risk of increased bleeding. Anticonvulsants: carbamazepine, clonazepam, ethosuximide ↑ anticonvulsants A dose decrease may be needed for these drugs when co-administered with ritonavir and therapeutic concentration monitoring is recommended for these anticonvulsants, if available. Anticonvulsants: divalproex, lamotrigine, phenytoin ↓ anticonvulsants A dose increase may be needed for these drugs when co-administered with ritonavir and therapeutic concentration monitoring is recommended for these anticonvulsants, if available.
Antidepressants: nefazodone, selective serotonin reuptake inhibitors (SSRIs): e.g. fluoxetine, paroxetine, tricyclics: e.g. amitriptyline, nortriptyline ↑ antidepressants A dose decrease may be needed for these drugs when co-administered with ritonavir. Antidepressant: bupropion ↓ bupropion ↓ active metabolite, hydroxybupropion Patients receiving ritonavir and bupropion concurrently should be monitored for an adequate clinical response to bupropion. Antidepressant: desipramine ↑ desipramine Dosage reduction and concentration monitoring of desipramine is recommended.
Antidepressant: trazodone ↑ trazodone Adverse events of nausea, dizziness, hypotension and syncope have been observed following co-administration of trazodone and ritonavir. A lower dose of trazodone should be considered. Antiemetic: dronabinol ↑ dronabinol A dose decrease of dronabinol may be needed when co-administered with ritonavir. Antifungals: ketoconazole itraconazole voriconazole ↑ ketoconazole ↑ itraconazole ↓…
Contraindications
When co-administering ritonavir with other protease inhibitors, see the full prescribing information for that protease inhibitor including contraindication information. Ritonavir is contraindicated in patients with known hypersensitivity (e.g., toxic epidermal necrolysis (TEN) or Stevens-Johnson syndrome) to ritonavir or any of its ingredients. Ritonavir is contraindicated with drugs that are highly dependent on CYP3A for clearance and for which elevated plasma concentrations are associated with serious and/or life-threatening reactions [see Drug Interactions ( 7.1 ) and Clinical Pharmacology ( 12.3 )] .
o Alpha 1- Adrenoreceptor Antagonist: alfuzosin o Antianginal: ranolazine o Antiarrhythmics: amiodarone, dronedarone, flecainide, propafenone, quinidine o Antifungal: voriconazole o Anti-gout: colchicine o Antipsychotics: lurasidone, pimozide o Ergot Derivatives: dihydroergotamine, ergotamine, methylergonovine o GI Motility Agent: cisapride o HMG-CoA Reductase Inhibitors: lovastatin, simvastatin o Microsomal triglyceride transfer protein (MTTP) Inhibitor: lomitapide o PDE5 Inhibitor: sildenafil (Revatio ® ) when used for the treatment of pulmonary arterial hypertension o Sedative/Hypnotics: triazolam, orally administered midazolam Ritonavir is contraindicated with drugs that are potent CYP3A inducers where significantly reduced ritonavir plasma concentrations may be associated with the potential for loss of virologic response and possible resistance and cross-resistance [see Drug Interactions ( 7.2 ) and Clinical Pharmacology ( 12.3 )] . o Anticancer Agents: apalutamide o Herbal Products: St. John's Wort (hypericum perforatum) Ritonavir is contraindicated in patients with known hypersensitivity to ritonavir (e.g., toxic epidermal necrolysis, Stevens-Johnson syndrome) or any of its ingredients. ( 4 ) Co-administration with drugs highly dependent on CYP3A for clearance and for which elevated plasma concentrations may be associated with serious and/or life-threatening events.( 4 ) Co-administration with drugs that significantly reduce ritonavir. ( 4 )
Pregnancy and lactation
Pregnancy
8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ritonavir during pregnancy. Healthcare providers are encouraged to register patients by calling the Antiretroviral Pregnancy Registry (APR) at 1-800-258-4263. Risk Summary Prospective pregnancy data from the Antiretroviral Pregnancy Registry (APR) are not sufficient to adequately assess the risk of birth defects or miscarriage. Available data from the APR show no difference in the rate of overall birth defects for ritonavir compared to the background rate for major birth defects of 2.7% in the U.S.
reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP) [see Data ]. In animal reproduction studies, no evidence of adverse developmental outcomes was observed with oral administration of ritonavir to pregnant rats and rabbits. During organogenesis in the rat and rabbit, systemic exposure (AUC) was approximately 1/3 lower than human exposure at the recommended daily dose. In the rat pre- and post-natal developmental study, maternal systemic exposure to ritonavir was approximately 1/2 of the exposure in humans at the recommended daily dose, based on a body surface area conversion factor [see Data ].
Ritonavir oral solution is not recommended during pregnancy because there is no known safe level of ethanol exposure during pregnancy [see Clinical Considerations, Dosage and Administration ( 2.3 ) and Warnings and Precautions ( 5.2 )] . The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.
Clinical Considerations Dose Adjustments During Pregnancy and the Postpartum Period Ritonavir oral solution contains approx. 43% ethanol (v/v) and approx. 27% (w/v) propylene glycol and is not recommended during pregnancy because there is no known safe level of ethanol exposure during pregnancy [see Dosage and Administration ( 2.3 ) and Warnings and Precautions ( 5.2 )] .
Data Human Data Based on prospective reports to the APR of approximately 6,100 live births following exposure to ritonavir-containing regimens (including over 2,800 live births exposed in the first trimester and over 3,200 live births exposed in the second and third trimesters), there was no difference in the rate of overall birth defects for…
For breastfeeding, also see LactMed (National Library of Medicine), which summarizes milk levels and infant effects.
Supply and cost
Drug shortage status
Recalls (last 24 months)
Therapeutic equivalence (Orange Book)
Price ladder
Not the price at the counterThese are not what a patient pays at the pharmacy counter. They are what pharmacies, health plans, and government buyers pay, before manufacturer rebates. A patient's cost depends on their insurance (copay, coinsurance, or deductible) or the pharmacy's cash price.