VYALEV
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VYALEV (VYALEV).
VYALEV (foslevodopa/foscarbidopa) is a combination of a levodopa prodrug (foslevodopa) and a carbidopa prodrug (foscarbidopa). Foslevodopa is converted to levodopa, which is decarboxylated to dopamine in the brain, restoring dopamine levels in the striatum. Foscarbidopa is converted to carbidopa, which inhibits peripheral decarboxylation of levodopa, increasing levodopa availability to the brain.
| Metabolism | Foslevodopa is converted to levodopa by alkaline phosphatase; levodopa is metabolized by aromatic L-amino acid decarboxylase (AAAD) and catechol-O-methyltransferase (COMT). Foscarbidopa is converted to carbidopa, which is metabolized by unidentified pathways. |
| Excretion | Foslevodopa is primarily eliminated renally as metabolites (levodopa and its metabolites, including 3-O-methyldopa and dopamine metabolites). Approximately 70-80% of the dose is excreted in urine, with <10% as unchanged levodopa. Fecal excretion accounts for <5%. Foscarbidopa is hydrolyzed to carbidopa, which is excreted mainly renally (60-70% as unchanged drug and metabolites). Biliary excretion is minimal. |
| Half-life | The terminal elimination half-life of levodopa from foslevodopa/foscarbidopa is approximately 2.5-3 hours. In the context of continuous subcutaneous infusion, steady-state concentrations are maintained without significant peaks and troughs, allowing for constant dopaminergic stimulation. The half-life of carbidopa is similar (2-3 hours). |
| Protein binding | Levodopa: approximately 10-30% bound to plasma proteins (primarily albumin). Carbidopa: approximately 36% bound to plasma proteins. |
| Volume of Distribution | Levodopa: Vd approximately 0.9-1.3 L/kg, indicating distribution into total body water with some tissue binding. Carbidopa: Vd approximately 1.0 L/kg. These values reflect wide distribution but limited CNS penetration of carbidopa. |
| Bioavailability | Subcutaneous administration: Bioavailability of levodopa from foslevodopa is approximately 80-90% relative to intravenous administration. Foscarbidopa is rapidly converted to carbidopa; bioavailability of carbidopa is similar. Continuous subcutaneous infusion provides predictable absorption without first-pass metabolism. |
| Onset of Action | Subcutaneous infusion: Therapeutic effect (improvement in motor symptoms) is typically observed within 30-60 minutes of initiation. A loading dose may provide faster onset. Oral administration: Not applicable; VYALEV is not available orally. |
| Duration of Action | Continuous subcutaneous infusion provides 24-hour coverage. The duration of action is directly related to infusion duration; motor benefits persist as long as the infusion runs. Upon discontinuation, symptoms return within 1-2 hours as drug levels decline. |
| Molecular Weight | 197.19 |
Subcutaneous once daily starting dose: foscarbidopa 240 mg/foslevodopa 24 mg, then titrate by 1 mL (60 mg/6 mg) increments, maximum 5 mL (300 mg/30 mg) per day.
| Dosage form | SOLUTION |
| Renal impairment | eGFR ≥30 mL/min: no adjustment. eGFR 15-29 mL/min: reduce dose by 50% and monitor. eGFR <15 mL/min or dialysis: not recommended. |
| Liver impairment | Mild (Child-Pugh A): no adjustment. Moderate (Child-Pugh B): reduce dose by 50%; use with caution. Severe (Child-Pugh C): contraindicated. |
| Pediatric use | Not approved for pediatric use; safety and efficacy not established in patients <18 years. |
| Geriatric use | No specific dose adjustment; monitor renal function and start at low end of dosing range due to age-related renal decline. |
| 1st trimester | Avoid use due to risk of fetal levodopa exposure and potential for impaired bone development based on animal studies. |
| 2nd trimester | Limited human data; animal studies show fetotoxicity at high doses. Use only if benefit outweighs risk. |
| 3rd trimester | May cause fetal bradycardia and decreased fetal movement; avoid near term due to risk of neonatal adverse effects. |
Clinical note
Comprehensive clinical and safety monograph for VYALEV (VYALEV).
| Placental transfer | Levodopa crosses the placenta; carbidopa transfer is limited but present. Animal studies show placental transfer. |
| Breastfeeding | Levodopa and carbidopa are excreted in breast milk in low levels. Monitor infant for potential adverse effects such as irritability or poor feeding. Consider using alternatives if possible. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to levodopa or carbidopaConcurrent use of non-selective MAO inhibitorsNarrow-angle glaucomaSuspicious undiagnosed skin lesions or history of melanoma
| Precautions | Risk of dopamine dysregulation syndrome, Risk of impulse control disorders, Cardiovascular effects including orthostatic hypotension and arrhythmias, Risk of falls due to dyskinesias, Potential for neuroleptic malignant syndrome-like symptoms with abrupt withdrawal, Ocular effects including blurred vision and diplopia, Risk of melanoma development |
| Food/Dietary | Avoid high-protein meals, as they may reduce levodopa absorption. No specific food interactions reported for the subcutaneous route; however, consistent dietary protein intake is recommended to minimize fluctuations in response. |
Loading safety data…
| Lactation Rating |
| L3 (Moderately Safe) |
| Teratogenic Risk | VYALEV (foslevodopa/foscarbidopa) is a prodrug combination of levodopa and carbidopa. No human data are available. In animal studies, levodopa caused visceral and skeletal malformations in rabbits at doses similar to human exposure; carbidopa showed no teratogenicity. First trimester exposure carries risk of congenital anomalies. Second and third trimester exposure may be associated with fetal growth restriction and preterm birth. Use only if benefit outweighs risk; consider alternative therapy. |
| Fetal Monitoring | Monitor maternal blood pressure, dyskinesias, and hepatic function. Fetal monitoring includes serial ultrasound for growth and anatomy. Consider non-stress testing and biophysical profile in third trimester. Monitor for preterm labor. Postnatal: observe infant for extrapyramidal effects, withdrawal symptoms, and growth parameters. |
| Fertility Effects | Levodopa may affect reproductive function by altering prolactin secretion. In women, levodopa can suppress prolactin, potentially affecting ovulation. In men, levodopa may increase libido but effects on spermatogenesis are unknown. Carbidopa is not expected to have significant fertility effects. VYALEV may impair female fertility via prolactin modulation. |
| Clinical Pearls | VYALEV (foslevodopa/foscarbidopa) is a continuous subcutaneous infusion prodrug of levodopa/carbidopa for advanced Parkinson's disease. Monitor for infusion site reactions, including nodule formation and infection. Assess for dyskinesias and neuropsychiatric effects (hallucinations, impulse control disorders). Titrate dose based on individual response; abrupt discontinuation may precipitate neuroleptic malignant syndrome. Caution in patients with history of melanoma, severe cardiovascular disease, or narrow-angle glaucoma. |
| Patient Advice | Do not stop the infusion suddenly without consulting your doctor. · Report any injection site redness, swelling, or warmth. · Avoid driving or operating heavy machinery until you know how VYALEV affects you. · Inform your doctor if you experience unusual urges (gambling, hypersexuality), hallucinations, or confusion. · Store the infusion system and cassettes properly as instructed. |