Methyl donor (homocystinuria)
Betaine
Brand names: Cystadane
Adult dose
Dose: 3g PO BD (titrate per homocysteine)
Route: Oral
Frequency: BD
Clinical pearls
- Cystathionine β-synthase deficiency / classical homocystinuria — adjunct to B6/B12/folate
- BIMDG metabolic guideline; UK metabolic centres
- Monitor methionine to avoid toxicity
Contraindications
- Hypersensitivity
Side effects
- Cerebral oedema (rare)
- Body odour
- Nausea
- Diarrhoea
- Increased plasma methionine
Interactions
- Folate / B6 / B12 (additive — usually combined)
Monitoring
- Plasma homocysteine
- Methionine
- Mental state
Reference: BNF; BIMDG; SmPC; https://bnf.nice.org.uk/drugs/betaine/. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.
Pathways
- Sepsis Screening and Sepsis Six · UK Sepsis Trust; NICE NG51; Surviving Sepsis Campaign 2021
- Unintentional Weight Loss Workup · NICE NG12; BSG
- Chronic Fatigue Workup · NICE NG206; BMJ Best Practice
- Lymphadenopathy Workup · NICE NG12; BMJ Best Practice
- Pre-op Medical Clearance · NICE NG45; ESC 2022
- Secondary Hypertension Workup · NICE NG136; ESH 2023