LAMIVUDINE AND 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: Approximately 70% excreted unchanged in urine via active renal secretion; minor metabolism to trans-sulfoxide metabolite (5-10%). Stavudine: 40% excreted unchanged in urine; partially metabolized by phosphorylation and oxidation. |
| Excretion | Lamivudine: Approximately 70% of dose excreted unchanged in urine via glomerular filtration and active tubular secretion; 5-10% as trans-sulfoxide metabolite; fecal excretion <10%. Stavudine: Approximately 40% of dose excreted unchanged in urine via glomerular filtration and active tubular secretion; remainder metabolized to thymine and other metabolites; renal excretion accounts for ~60% of elimination. |
| Half-life | Lamivudine: Terminal half-life 5-7 hours (adults) to 10-12 hours (neonates); intracellular triphosphate half-life 10.5-15.5 hours, allowing once-daily dosing. Stavudine: Terminal half-life 1.0-1.6 hours but intracellular triphosphate half-life 3.5-4 hours, supporting twice-daily dosing. |
| Protein binding | Lamivudine: <36% bound to plasma proteins (primarily albumin). Stavudine: Negligible protein binding (<5%). |
| Volume of Distribution | Lamivudine: Approximately 1.3 L/kg (adults), indicating distribution into total body water and intracellular compartments; penetrates CSF (CSF:plasma ratio ~0.05-0.2). Stavudine: Approximately 0.5 L/kg (adults), indicating distribution into total body water; penetrates CSF (CSF:plasma ratio ~0.15-0.4). |
| Bioavailability | Lamivudine: Oral bioavailability ~80-90% in adults; reduced with food but not clinically significant; pediatric solution slightly lower. Stavudine: Oral bioavailability ~80-90%; not significantly affected by food. |
| Onset of Action | Lamivudine: Antiviral activity begins within 1-2 hours after oral administration; maximal inhibition of viral replication occurs within 2-4 weeks. Stavudine: Antiviral activity begins within 1-2 hours after oral administration; maximal viral load reduction occurs within 2-4 weeks. |
| Duration of Action | Lamivudine: Duration of antiviral effect approximately 12-24 hours for wild-type HIV; due to long intracellular half-life, supports once-daily dosing. Stavudine: Duration of antiviral effect approximately 8-12 hours; requires twice-daily dosing for sustained suppression; intracellular persistence may suppress virus for up to 12 hours. |
| Molecular Weight | Lamivudine: 229.25 Da; Stavudine: 224.21 Da |
Lamivudine 150 mg and stavudine 30-40 mg (depending on body weight: <60 kg: stavudine 30 mg; ≥60 kg: stavudine 40 mg) orally twice daily.
| Dosage form | TABLET |
| Renal impairment | For lamivudine: GFR 30-49 mL/min: 150 mg once daily; GFR 15-29 mL/min: 100 mg once daily (using oral solution); GFR 5-14 mL/min: 50 mg once daily; GFR <5 mL/min: 25 mg once daily. For stavudine: GFR >50 mL/min: no adjustment; GFR 26-50 mL/min: 50% of usual dose (e.g., 20 mg twice daily if ≥60 kg); GFR 10-25 mL/min: 50% of usual dose every 24 hours; GFR <10 mL/min: 50% of usual dose every 24 hours (or consider dose based on level). Hemodialysis: administer after dialysis. |
| Liver impairment | No dose adjustment required for lamivudine in hepatic impairment. For stavudine: no specific guidelines; use with caution in severe hepatic impairment due to risk of lactic acidosis. |
| Pediatric use | Lamivudine: 4 mg/kg (max 150 mg) orally twice daily. Stavudine: body weight <30 kg: 1 mg/kg (max 30 mg) orally twice daily; 30-60 kg: 30 mg twice daily; >60 kg: 40 mg twice daily. |
| Geriatric use | No specific geriatric dose adjustments; use with caution due to age-related renal function decline. Adjust doses based on creatinine clearance. |
| 1st trimester | Use only if clearly needed; risk of lactic acidosis/hepatic steatosis. Human data limited but teratogenicity not established; however, combination with stavudine may exacerbate mitochondrial toxicity. |
| 2nd trimester | Continue if maternal benefit outweighs risk; monitor for anemia, pancreatitis, and lactic acidosis. |
| 3rd trimester | Continue; risk of lactic acidosis and hepatic steatosis remains. Stavudine is associated with higher risk of mitochondrial toxicity in infants. |
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 has extensive transfer (cord blood concentrations similar to maternal); stavudine transfer is moderate but less than lamivudine. |
■ FDA Black Box Warning
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues alone or in combination, including lamivudine and stavudine. Fatal lactic acidosis has been reported in pregnant women receiving combination of stavudine and didanosine with other antiretroviral agents.
| Common Effects | Peripheral neuropathy |
| Serious Effects |
Hypersensitivity to lamivudine or stavudineLactic acidosis or hepatic steatosis (especially with stavudine)Peripheral neuropathy (stavudine)Pancreatitis (especially with history)
| Precautions | Lactic acidosis and severe hepatomegaly with steatosis, Pancreatitis (especially in children with prior nucleoside exposure), Peripheral neuropathy, Lipodystrophy, Immune reconstitution syndrome, Hepatotoxicity in patients with hepatitis B or C coinfection, Redistribution/accumulation of body fat |
| Food/Dietary |
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| Breastfeeding | Lamivudine and stavudine are excreted into human milk. Lamivudine in breast milk achieves clinically relevant concentrations; stavudine is present at lower levels. Avoid breastfeeding if other antiretroviral options available due to risk of mitochondrial toxicity and development of drug resistance in infants. |
| Lactation Rating | L4 (Possibly Hazardous) |
| Teratogenic Risk | Lamivudine and Stavudine: Lamivudine is FDA Pregnancy Category C; stavudine is Category C. Lamivudine crosses placenta; no increased risk of major malformations observed in first trimester. Stavudine may be associated with mitochondrial toxicity and lactic acidosis in neonates. Both are used in antiretroviral therapy during pregnancy; risk of HIV transmission reduction outweighs potential fetal risks. Second and third trimesters: continued use with monitoring for maternal/fetal adverse effects. |
| Fetal Monitoring | Maternal: Liver function tests, serum lactate, amylase, complete blood count, renal function, HIV viral load, CD4 count. Fetal: Ultrasound for congenital anomalies (if exposed in first trimester), growth monitoring, neonatal mitochondrial toxicity evaluation (especially with stavudine). Monitor for lactic acidosis/hepatic steatosis syndrome. |
| Fertility Effects | Lamivudine and Stavudine: No significant adverse effects on female or male fertility reported in animal studies. In humans, no definitive evidence of impaired fertility. However, antiretroviral therapy may affect hormonal indices in women; data limited. |
| No specific food interactions; take with or without food. Avoid alcohol as it may increase risk of liver toxicity. |
| Clinical Pearls | Monitor for lactic acidosis and hepatomegaly with steatosis, especially in women and obese patients. Assess renal function before initiating stavudine; reduce dose if CrCl <50 mL/min. Lamivudine and stavudine should not be coadministered due to antagonism and increased risk of peripheral neuropathy. Check for hepatitis B coinfection before starting lamivudine due to risk of exacerbation upon discontinuation. Peripheral neuropathy is dose-limiting for stavudine; use alternative agents in patients at high risk. |
| Patient Advice | Take this combination exactly as prescribed; do not skip doses. · Report symptoms of lactic acidosis (e.g., unexplained fatigue, muscle pain, rapid breathing) or liver problems (e.g., dark urine, jaundice, abdominal pain) immediately. · Stop taking the medication and contact your doctor if you develop numbness, tingling, or pain in the hands or feet. · Do not take this combination with other HIV medications without your doctor's approval. · If you have hepatitis B, do not stop lamivudine without consulting your doctor; sudden stop can worsen liver disease. · Use effective contraception if applicable; this medication does not prevent transmission of HIV. |