Pyridoxine Syrup Formulations
Pyridoxine is available as an elixir/syrup formulation at 50 mg/5 mL concentration, which is the standard liquid preparation for pediatric use. 1
Available Liquid Formulation
- The commercially available pyridoxine syrup contains 50 mg per 5 mL (10 mg/mL concentration). 1
- This formulation allows precise dosing for infants requiring 10–25 mg daily supplementation during cycloserine therapy. 1
Dosing Calculation for Infant Use
- For a 10 mg daily dose: administer 0.5 mL of the 50 mg/5 mL syrup
- For a 25 mg daily dose: administer 1.25 mL of the 50 mg/5 mL syrup
- The syrup formulation enables accurate measurement using an oral syringe for small pediatric doses. 1
Clinical Context for Cycloserine Therapy
- Pyridoxine supplementation is mandatory when cycloserine is administered to prevent peripheral neuropathy, similar to isoniazid prophylaxis. 1
- The recommended dose for infants on cycloserine is 10–25 mg daily, which falls within the safe prophylactic range. 1
- This dose is far below the toxicity threshold (>100 mg/day chronically), providing a wide safety margin. 2
Alternative Formulations if Syrup Unavailable
- Tablets are available in 50 mg, 100 mg, and 300 mg strengths, but these are impractical for precise infant dosing. 1
- If syrup is unavailable, tablets can be crushed and suspended in water, though this is an off-label preparation requiring careful measurement. 3
- Aqueous injectable solution (100 mg/mL) exists for IV/IM use but is not appropriate for routine oral supplementation. 1
Critical Safety Considerations
- The 50 mg/5 mL syrup contains sorbitol as an excipient, which may cause diarrhea in some infants—monitor for loose stools. 1
- Do not confuse prophylactic dosing (10–25 mg daily) with treatment doses for acute cycloserine-induced seizures, which require much higher pyridoxine doses administered parenterally. 4
- Ensure the infant receives pyridoxine daily throughout the entire duration of cycloserine therapy to maintain neuroprotection. 1