Neuromuscular blocker (presynaptic)

Botulinum toxin type A

Brand names: Botox, Dysport, Xeomin, Bocouture

Adult dose

Dose: Indication-specific — ranges from 12.5–500 units total per session per product

Route: Intramuscular / Intradetrusor / Intradermal

Frequency: q3–6 months typically

Clinical pearls

Multiple NICE TAs/CGs: chronic migraine (TA260), spasticity, focal dystonia, blepharospasm, hyperhidrosis (TA32 historic), overactive bladder (TA290)
ABN spasticity, NICE NG46
Brand non-interchangeable — units differ

Contraindications

Active infection at injection site
Myasthenia gravis / Lambert-Eaton
Pregnancy/breastfeeding
Hypersensitivity

Side effects

Local muscle weakness
Distant spread (dysphagia, ptosis, generalised weakness — boxed warning, MHRA)
Dysarthria
Dry eye
Urinary retention (intradetrusor)

Interactions

Aminoglycosides (potentiate)
Other neuromuscular blockers
Anticholinergics

Monitoring

Therapeutic response
Adverse effect distant spread
Anti-BoNT antibodies (loss of effect)

Reference: BNF; NICE TA260; NICE TA290; ABN spasticity; MHRA Drug Safety Update; SmPC; https://bnf.nice.org.uk/drugs/botulinum-toxin-type-a/. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways