LAMIVUDINE; STAVUDINE
Clinical safety rating: safe
Other drugs that cause peripheral neuropathy or pancreatitis increase risk Can cause peripheral neuropathy and pancreatitis.
Lamivudine is a nucleoside reverse transcriptase inhibitor (NRTI) that inhibits HIV-1 reverse transcriptase via DNA chain termination after intracellular phosphorylation to lamivudine triphosphate. Stavudine is also an NRTI that inhibits HIV-1 reverse transcriptase after phosphorylation to stavudine triphosphate.
| Metabolism | Lamivudine is primarily eliminated renally as unchanged drug; minor hepatic metabolism (<10%). Stavudine is eliminated renally as unchanged drug; no significant metabolism by CYP450 enzymes. |
| Excretion | Lamivudine: 70% renal excretion via glomerular filtration and active tubular secretion as unchanged drug; 5-10% fecal. Stavudine: 40% renal excretion via glomerular filtration and active tubular secretion; 34-39% unchanged in urine; fecal excretion minimal. |
| Half-life | Lamivudine: 5-7 hours in adults; prolonged to 19-28 hours in severe renal impairment (CrCl <10 mL/min). Stavudine: 1.0-1.6 hours; prolonged to 7.4-8.2 hours in severe renal impairment. |
| Protein binding | Lamivudine: <36% bound to plasma albumin. Stavudine: <1% bound to plasma proteins. |
| Volume of Distribution | Lamivudine: 1.3 L/kg, indicating distribution into total body water; crosses placenta and enters breast milk. Stavudine: 0.5 L/kg, approximates total body water; penetrates into cerebrospinal fluid (CSF-to-plasma ratio 0.16-0.97). |
| Bioavailability | Lamivudine: oral 86-88% (tablet and solution); food delays absorption but does not reduce AUC. Stavudine: oral 86-86.4% (capsule and solution); food reduces Cmax and AUC by 30-40%. |
| Onset of Action | Lamivudine: oral, 1-2 hours to peak plasma concentration; clinical antiviral effect within 2-4 weeks. Stavudine: oral, 0.5-1.5 hours to peak plasma concentration; clinical effect within 2-4 weeks. |
| Duration of Action | Lamivudine: 12-24 hours with twice-daily dosing; intracellular active metabolite triphosphate has half-life of 10.5-15.5 hours supporting once-daily dosing. Stavudine: 8-12 hours with twice-daily dosing; intracellular active metabolite triphosphate has half-life of 3.5 hours. |
| Molecular Weight | Lamivudine: 229.3 Da; Stavudine: 224.2 Da |
Lamivudine 150 mg plus stavudine 30 mg orally twice daily. For patients weighing ≥60 kg, stavudine 40 mg twice daily.
| Dosage form | TABLET |
| Renal impairment | For lamivudine: CrCl 30-49 mL/min: 150 mg once daily; CrCl 15-29 mL/min: 150 mg first dose then 100 mg once daily; CrCl 5-14 mL/min: 150 mg first dose then 50 mg once daily; CrCl <5 mL/min: 50 mg first dose then 25 mg once daily. For stavudine: CrCl 26-50 mL/min: 50% of usual dose; CrCl 10-25 mL/min: 25% of usual dose; CrCl <10 mL/min: data insufficient, use with caution. |
| Liver impairment | For stavudine: Child-Pugh class A or B: no adjustment; Child-Pugh class C: dose not established, use with caution. For lamivudine: no adjustment required in hepatic impairment. |
| Pediatric use | Lamivudine: 4 mg/kg (max 150 mg) twice daily; Stavudine: weight <30 kg: 1 mg/kg twice daily; weight 30-60 kg: 30 mg twice daily; weight >60 kg: adult dose. |
| Geriatric use | Use with caution due to age-related renal impairment. Monitor renal function and adjust doses accordingly based on CrCl. Start at lower end of dosing range. |
| 1st trimester | Use during first trimester only if benefit outweighs risk; associated with limited data but not major teratogen in animal studies. |
| 2nd trimester | Use if clearly needed; monitor for mitochondrial toxicity and lactic acidosis. |
| 3rd trimester | Use if clearly needed; monitor for lactic acidosis/hepatic steatosis. |
Clinical note
Other drugs that cause peripheral neuropathy or pancreatitis increase risk Can cause peripheral neuropathy and pancreatitis.
| FDA category | Animal |
| Placental transfer | Both drugs cross the placenta. Lamivudine: extensive transfer, with cord blood levels similar to maternal. Stavudine: moderate transfer, lower cord blood levels compared to maternal. |
| Breastfeeding |
■ FDA Black Box Warning
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues including lamivudine and stavudine. Stavudine in combination with didanosine is associated with a high risk of lactic acidosis and hepatotoxicity. Pancreatitis, sometimes fatal, has occurred with stavudine use.
| Common Effects | Peripheral neuropathy |
| Serious Effects |
Hypersensitivity to drug or componentsConcomitant use with doxorubicin or ribavirin (increased toxicity)
| Precautions | Monitor for lactic acidosis, hepatotoxicity, pancreatitis, peripheral neuropathy, lipodystrophy, immune reconstitution syndrome, and mitochondrial toxicity. Dose adjustment required for renal impairment. Coinfection with hepatitis B or C may increase risk of hepatotoxicity. |
| Food/Dietary |
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| Lamivudine and stavudine are excreted into human milk. Potential for adverse effects in nursing infants including mitochondrial toxicity. Consider alternatives or advise formula feeding. |
| Lactation Rating | L4 (Possibly Hazardous) |
| Teratogenic Risk | Lamivudine and stavudine are classified as FDA Pregnancy Category C. There are no adequate and well-controlled studies in pregnant women. Animal studies have shown embryotoxicity at high doses. First trimester exposure: limited data suggest no major increase in birth defects. Second and third trimester: use primarily for maternal benefit; may reduce vertical transmission of HIV. Placental transfer occurs; both drugs cross the placenta. Risk of mitochondrial toxicity in neonates exposed in utero. |
| Fetal Monitoring | Maternal: complete blood count, liver function tests, renal function, serum lactate, and amylase at baseline and periodically; viral load and CD4+ count every 1-3 months; HIV genotype before initiation. Fetal/neonatal: growth ultrasound for potential growth restriction; HIV testing at birth, 6 weeks, and 4-6 months; monitor for signs of lactic acidosis and pancreatitis in the neonate. |
| Fertility Effects | No definitive evidence of adverse effects on fertility in humans. Animal studies have not shown impaired fertility at clinically relevant doses. HIV infection itself may affect fertility; antiretroviral therapy may improve fertility by improving health status. |
| No significant food interactions. Absorption unaffected by food. Avoid alcohol due to increased risk of pancreatitis and hepatotoxicity. |
| Clinical Pearls | Monitor for mitochondrial toxicity (e.g., hepatomegaly, pancreatitis, lactic acidosis) especially with prolonged use. Avoid co-administration with didanosine due to increased risk of pancreatitis. Adjust dose for renal impairment (CrCl <50 mL/min). Watch for immune reconstitution syndrome in HIV patients. Stavudine may cause peripheral neuropathy; discontinue if symptoms occur. |
| Patient Advice | Take this medication exactly as prescribed, with or without food. · Do not share your medication with others. · Report immediately if you experience numbness, tingling, or pain in hands/feet (peripheral neuropathy). · Watch for symptoms of pancreatitis: severe abdominal pain, nausea, vomiting. · Signs of lactic acidosis: weakness, unusual muscle pain, trouble breathing, slow/irregular heartbeat. · This medication does not cure HIV but helps reduce viral load and prevent transmission. · Regular blood tests are needed to monitor kidney function, liver enzymes, and blood counts. · Inform your doctor of all other medications, especially other antiretrovirals. · Do not stop taking this drug without consulting your physician, as viral resistance may develop. |