II. Indications
- Used at low dose to "boost" most of the Protease Inhibitors
III. Mechanism
IV. Medications
- Most Protease Inhibitors are "boosted" with either Ritonavir or Cobicistat (Tybost)
- Ritonavir (Norvir) used at low dose in combination with other Protease Inhibitors
- Ritonavir at high standard dose is limited by adverse gastrointestinal effects
- Suffix '/r' added when a protease inhibutor is combined with Ritonavir
- Examples of Combinations with Ritonavir
- Formulations
- Tablets or Capsules: 100 mg
- Oral Powder: 100 mg/packet
- Oral Solution: 80 mg/ml
- Ritonavir solution contains Alcohol and propylene glycol
- Risk of propylene glycol and Alcohol Toxicity in infants age <6 months (esp <4 weeks)
- With Feeding Tube administration, use only silicone or PVC
- Avoid polyurethane tubing due to Alcohols in solution
V. Dosing: Adult
- Take with food
- Anticipate bad taste (Mix with Chocolate milk)
- Boosting dose (added to other Protease Inhibitors)
- Typical boosting dose: 100 mg daily
- Boosting Doses as high as 400 mg twice daily have been used in some protocols
- Full dose (non-boosting)
- Take 600 mg orally twice daily
- Full dose is not typically used due to adverse effects (esp. gastrointestinal)
VI. Dosing: Child
- See specific dosing protocols in which Ritonavir is used as the boosting agent
VII. Adverse Effects
- Adverse effects reflect Ritonavir used at full dose
- Adverse effects are less common with the lower, "boosting dose"
- Gastrointestinal (adverse effects may limit medication use)
- Asthenia
- Paresthesias (Circumoral or peripheral)
- Pancreatitis
- Triglycerides elevated
-
Liver Function Tests
- Cholestatic enzymes elevated
- Hepatic transaminases elevated
- Electrocardiogram changes
VIII. Safety
- Avoid in Lactation
- Pregnancy
- Pregnancy registry exists
- Frequently used in pregnancy added in low dose to other Protease Inhibitors
IX. Drug Interactions
- Multiple Drug Interactions
- See Protease Inhibitor
- Ritonavir, even at its lower boosting dose, has numerous Drug Interactions
- As with other Protease Inhibitors, check a formal Drug Interaction application before prescribing
- Many contraindicated drugs (do not coadminister)
- Check a formal Drug Interaction application before prescribing
- Examples include Amiodarone, Flecainide, Propafenone, Quinidine, rivaroxiban
-
Oral Contraceptives (OCP)
- Decreased OCP effectiveness
- Use backup or alternative Contraception
-
Voriconazole
- Ritonavir (esp. at 400 mg twice daily) decreases Voriconazole levels and efficacy
- Avoid concurrent use if possible
- Opioids
-
Clarithromycin
- Decrease Clarithromycin dose if Creatinine Clearance <60 ml/min
-
Didanosine
- Didanosine is buffered with decreased Ritonavir oral absorption
- Take Ritonavir at least 2.5 hours before or after Didanosine
-
Digoxin
- Ritonavir may increase Digoxin levels
X. Efficacy
- Very effective when "boosting" other Protease Inhibitors
XI. Resources
Images: Related links to external sites (from Bing)
Related Studies
| ritonavir (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| RITONAVIR 100 MG TABLET | Generic | $1.08 each |
| norvir (on 4/20/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| NORVIR 100 MG TABLET | Generic | $1.08 each |
Ontology: Ritonavir (C0292818)
| Definition (NCI_NCI-GLOSS) | A drug used to treat infection with HIV (the virus that causes AIDS). It is also being studied in the treatment of some types of cancer. Ritonavir blocks the ability of HIV to make copies of itself and may block the growth of cancer cells. It is a type of anti-HIV agent and a type of protease inhibitor. |
| Definition (NCI) | A peptidomimetic agent that inhibits both HIV-1 and HIV-2 proteases. Ritonavir is highly inhibited by serum proteins but boosts the effect of other HIV proteases by blocking their degradation by cytochrome P450. |
| Definition (MSH) | An HIV protease inhibitor that works by interfering with the reproductive cycle of HIV. It also inhibits CYTOCHROME P-450 CYP3A. |
| Definition (CSP) | HIV protease inhibitor that works by interfering with the replication cycle of HIV. |
| Definition (PDQ) | A synthetic aromatic derivative with antiviral properties. Ritonavir is a peptidomimetic agent that inhibits both HIV-1 and HIV-2 proteases, thereby preventing the cleavage of Gag-Pol polyproteins and resulting in the production of noninfectious viral particles. This agent is more active against HIV-1. Because ritonavir targets the HIV replication cycle after translation and before assembly, it is active in chronically infected cells that generally are not affected by nucleoside reverse transcriptase inhibitors. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=42665&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=42665&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C1609" NCI Thesaurus) |
| Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
| MSH | D019438 |
| SnomedCT | 108693005, 386896009 |
| LNC | LP21314-7, MTHU013855 |
| English | RTV, Ritonavir, ritonavir, RIT, ritonavir (medication), RITONAVIR, Ritonavir [Chemical/Ingredient], Ritonavir (product), Ritonavir (substance) |
| Swedish | Ritonavir |
| Czech | ritonavir |
| Finnish | Ritonaviiri |
| Russian | RITONAVIR, РИТОНАВИР |
| Japanese | リトナビル |
| Polish | Rytonawir |
| Spanish | ritonavir (producto), ritonavir (sustancia), ritonavir, Ritonavir |
| French | Ritonavir |
| German | Ritonavir |
| Italian | Ritonavir |
| Portuguese | Ritonavir |
