RESCRIPTOR
Clinical safety rating: caution
Comprehensive clinical and safety monograph for RESCRIPTOR (RESCRIPTOR).
Non-nucleoside reverse transcriptase inhibitor (NNRTI) that binds directly to HIV-1 reverse transcriptase, causing conformational change and inhibiting RNA-dependent DNA polymerase activity.
| Metabolism | Hepatic via CYP3A4; also metabolized by CYP2D6 |
| Excretion | Renal: 51% (unchanged drug) and 44% (glucuronide metabolite); biliary/fecal: <5%. Total recovery in urine is approximately 95%. |
| Half-life | Terminal elimination half-life is 2.5–4.5 hours in adults. This short half-life necessitates twice-daily dosing. In patients with hepatic impairment, half-life may be prolonged. |
| Protein binding | ~98% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Vd/F = approximately 0.7–1.2 L/kg (apparent volume of distribution). Widely distributed into tissues, including cerebrospinal fluid (CSF concentration ~20% of plasma). |
| Bioavailability | Oral bioavailability is approximately 85% (range 75–95%) after oral administration of the tablet formulation. |
| Onset of Action | Oral administration: peak plasma concentrations occur within 2 hours. Antiviral effect is typically observed within 1–2 days of therapy initiation. |
| Duration of Action | Duration of antiviral effect is approximately 12 hours, corresponding to dosing interval (every 12 hours). Consistent drug levels are required for efficacy; missed doses may lead to viral rebound. |
400 mg orally three times daily.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment; insufficient data for severe impairment (CrCl <30 mL/min) or hemodialysis. |
| Liver impairment | Mild to moderate hepatic impairment (Child-Pugh A or B): no adjustment. Severe impairment (Child-Pugh C): contraindicated. |
| Pediatric use | Not approved for pediatric patients; safety and efficacy not established. |
| Geriatric use | No specific dose adjustment recommended; use caution due to age-related renal and hepatic decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for RESCRIPTOR (RESCRIPTOR).
| Breastfeeding | Not recommended; extensive hepatic metabolism suggests low excretion, but safety not established. M/P ratio unknown. Avoid breastfeeding during therapy. |
| Teratogenic Risk | Insufficient human data; animal studies show no evidence of teratogenicity up to 50 mg/kg/day. Risk cannot be ruled out; use only if benefit justifies risk. No trimester-specific risks identified. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Concomitant use with drugs that are highly dependent on CYP3A4 for clearance and for which elevated plasma concentrations are associated with serious adverse events (e.g., astemizole, terfenadine, dihydroergotamine, ergotamine, midazolam, triazolam, cisapride, pimozide).","History of clinically significant hypersensitivity to delavirdine or any component of the formulation."]
| Precautions | ["Hepatotoxicity: severe hepatic events reported, including hepatitis and hepatic failure; monitor liver enzymes.","Skin reactions: severe cutaneous reactions including Stevens-Johnson syndrome and toxic epidermal necrolysis reported; discontinue if rash with systemic symptoms.","Immune reconstitution syndrome.","Fat redistribution and accumulation."] |
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| Monitor liver function tests, renal function, and complete blood counts monthly. Assess for rash (including severe cutaneous reactions) and monitor for peripheral neuropathy. Fetal ultrasound for growth if used during pregnancy. |
| Fertility Effects | No human data; animal studies show no impaired fertility at clinically relevant doses. Theoretical risk of hormonal disruption but not observed. |