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. |
| Molecular Weight | 456.5 |
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 | Use only if benefit outweighs risk; teratogenic in animal studies, no adequate human data. |
| 2nd trimester | Use only if benefit outweighs risk; may cause fetal harm based on animal data. |
| 3rd trimester | Use only if benefit outweighs risk; consider risk of neonatal withdrawal and toxicity. |
Clinical note
Comprehensive clinical and safety monograph for RESCRIPTOR (RESCRIPTOR).
| Placental transfer | Crosses placenta in animal studies; human data limited. |
| Breastfeeding | Excreted in breast milk; potential for serious adverse reactions in nursing infants; discontinue nursing or drug. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to delavirdine or any componentConcomitant use with drugs that are CYP3A inducers or substrates with narrow therapeutic index (e.g., rifampin, astemizole, terfenadine, ergot derivatives) due to risk of toxicity or loss of efficacy
| 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. |
| Food/Dietary | No specific food restrictions; absorption not significantly affected by food. Avoid grapefruit juice as it may increase drug levels. |
Loading safety data…
| L4 |
| 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 | 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. |
| Clinical Pearls | RESCRIPTOR (delavirdine) is an NNRTI used in combination antiretroviral therapy. Monitor for rash, especially in first 2-4 weeks; can be severe but often self-limited. Avoid coadministration with drugs that are strong CYP3A inducers or substrates with narrow therapeutic index (e.g., rifampin, ergot derivatives). Hepatic impairment requires caution. |
| Patient Advice | Take this medication exactly as prescribed with or without food. · Do not stop taking this medication without consulting your doctor; missing doses can lead to drug resistance. · Report any new rash, especially if accompanied by fever or blisters, to your healthcare provider immediately. · This medication does not cure HIV and you can still transmit the virus; practice safe sex and avoid sharing needles. · Inform all healthcare providers you are taking delavirdine, as it interacts with many other medications. |