foscarbidopa + foslevodopa: clinical use

Prescribing considerations

• Specialist selection and initiation are required; the patient or caregiver must be able to manage the pump and infusion system.
• Avoid abrupt withdrawal and establish a contingency plan for prolonged interruption or device failure.
• Consider cardiovascular, pulmonary, renal, hepatic, endocrine, psychiatric, ulcer and seizure histories.
• The formulation is high in sodium, which may matter for people following sodium restriction.
• Foscarbidopa produces hydrazine, a genotoxic and probably carcinogenic degradation product; the clinical significance of exposure is unknown.

Contraindications and cautions

• Hypersensitivity to either active substance or an excipient
• Narrow-angle glaucoma
• Severe heart failure, severe cardiac arrhythmia or acute stroke
• Concurrent non-selective MAO inhibition or selective MAO-A inhibition
• Phaeochromocytoma, hyperthyroidism or Cushing’s syndrome
• Suspicious undiagnosed skin lesions or a history of melanoma

Monitoring

• Motor response, dyskinesia and sudden worsening that could indicate device obstruction
• Infusion-site reactions, abscess, cellulitis or systemic infection
• Postural blood pressure, somnolence and sudden sleep episodes
• Hallucinations, psychosis, depression, suicidality and impulse-control disorders
• Peripheral neuropathy symptoms and relevant risk factors
• Periodic haematological, hepatic, renal and cardiovascular assessment during extended treatment
• Skin surveillance for melanoma

Clinical pharmacology

Foslevodopa and foscarbidopa are soluble phosphate prodrugs converted in vivo to levodopa and carbidopa. Carbidopa inhibits peripheral levodopa decarboxylation without materially crossing the blood–brain barrier, increasing levodopa availability for central conversion to dopamine. Subcutaneous infusion produces relatively steady levodopa exposure.

Formulation and product differences

• Ready-to-use solution for continuous subcutaneous infusion rather than an oral or intestinal levodopa formulation.
• Used only with the specified portable pump and compatible sterile, single-use components.
• Expected colour variation from colourless to yellow or brown, sometimes with a red or purple tint, does not itself indicate reduced quality.
• Vials are single use; the solution must not be diluted or mixed with other medicines.
• Store refrigerated without freezing and bring to room temperature naturally before infusion.

Solution for infusion

Route: Intravenous

Strengths: 240 mg/mL + 12 mg/mL