Neurotoxin — Therapeutic / Cosmetic Pregnancy: Contraindicated — avoid in pregnancy and breastfeeding

Botulinum Toxin Type A

Brand names: Botox (onabotulinumtoxinA), Dysport (abobotulinumtoxinA), Bocouture (incobotulinumtoxinA), Azzalure

Adult dose

Dose: Glabellar lines: 20 units Botox (4 units × 5 points); Hyperhidrosis: 50–100 units per axilla; Spasticity/scar management: 50–200 units per session

Route: Intramuscular / Intradermal (hyperhidrosis/scars)

Frequency: Every 3–4 months (cosmetic); every 6 months (therapeutic)

Max: 400 units per session (Botox); equivalent doses for other brands (NOT interchangeable — different unit systems)

Different brands are NOT dose-equivalent: 1 unit Botox ≈ 2.5–3 units Dysport ≈ 1 unit Bocouture. In burns/plastics: used for scar management (reducing wound tension), wound healing, and hyperhidrosis. Therapeutic indications (licensed): blepharospasm, hemifacial spasm, spasticity, hyperhidrosis, migraine, overactive bladder.

Paediatric dose

Dose: 4–8 units/kg

Route: Intramuscular

Frequency: Every 3–6 months

Max: 200 units per session

Cerebral palsy spasticity: 4 units/kg per muscle group under specialist guidance. Drooling: 25 units per parotid gland.

Dose adjustments

Renal

No dose adjustment required.

Hepatic

No adjustment required.

Paediatric weight-based calculator

Patient weight (kg)

Cerebral palsy spasticity: 4 units/kg per muscle group under specialist guidance. Drooling: 25 units per parotid gland.

Clinical pearls

Different brand units are NOT interchangeable — prescribe by brand name and specify units to avoid dangerous dose errors
Scar management: intradermal BTX-A reduces scar tension by relaxing underlying muscle — particularly studied for midline abdominal, sternotomy, and facial scars. Improves wound cosmesis.
Licence status: many uses are off-label (scar management, wound tension reduction) — document consent and rationale carefully

Contraindications

Myasthenia gravis
Lambert-Eaton syndrome
Neuromuscular junction disorders
Infection at injection site
Hypersensitivity to botulinum toxin

Side effects

Local bruising and pain at injection site
Ptosis (periorbital injections)
Dysphagia (cervical/oropharyngeal injections)
Headache (post-injection)
Spread to adjacent muscles (dose-dependent)
Generalised weakness (extremely rare)
Antibody formation (reduced efficacy with frequent dosing)

Interactions

Aminoglycosides (potentiate neuromuscular blockade)
Anticholinergic drugs (additive effects)
NMB agents (potentiation)
Quinidine (potentiates blockade)

Monitoring

Clinical response at 2–4 weeks (therapeutic effect onset)
Signs of spread to adjacent structures (ptosis, dysphagia)
Antibody testing if reduced response with repeated use

Reference: BNFc; BNF 90; MHRA Botulinum Toxin Guidance; BAPRAS (British Association of Plastic, Reconstructive and Aesthetic Surgeons) Scar Management Guidelines. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators