Botulinum Toxin Type A (ENT)

How it works

It blocks presynaptic release of acetylcholine at the neuromuscular junction and cholinergic autonomic terminals, producing temporary, dose-dependent weakening of injected muscle or reduction of glandular secretion.

Prescribing in practice

• Different botulinum toxin products are not interchangeable in units and dosing errors can cause toxin spread with serious effects such as dysphagia, aspiration or breathing difficulty, so the specific product and indication must be confirmed and injection performed by appropriately trained clinicians.
• Effects are temporary, developing over days and lasting some months, so repeat treatment is generally needed.
• Use cautiously in patients with neuromuscular disorders (such as myasthenia gravis) or pre-existing swallowing problems, who are more prone to adverse effects.

Monitoring

Assess the targeted clinical effect and watch for local spread effects such as new or worsening swallowing or voice difficulty after each treatment.

Counselling the patient

• The effect is temporary and usually needs repeating after a few months.
• Seek urgent help for difficulty swallowing, breathing or speaking after injection.
• Voice or swallowing may change for a short period after laryngeal injection.

Evidence & guidelines

Local botulinum toxin injection is the established treatment for adductor spasmodic dysphonia and an option for refractory sialorrhoea.