Onabotulinum Toxin A
for Migraine
Migraine Ireland
How does it work?
BOTOX blocks the release of neuro-transmitters that are linked to causing pain. Neuro-transmitters are chemicals that carry nerve impulses. To prevent headache, Botox blocks these signals from reaching the central nervous system and causing the nerves to become highly sensitive.
Botox is given by injection; divided across seven specific head/neck muscle areas. The number of injection sites start at 31, up to a maximum of 39. Half the injection sites should be on the left side of the head and half on the right. If there is a predominant pain location, further injections may be given (up to the maximum dosage). The injections should be given by trained personnel in hospital or specialist centres.
Always make sure that you see a doctor who is trained in administering botox for migraine, and not for cosmetic reasons. Training is now beginning across Ireland.
The recommended re-treatment schedule is every twelve weeks. No efficacy has been shown for BOTOX in preventing headaches in patients with episodic migraine (headaches on less than fifteen days per month).
Safety and side effects
In clinical trials for chronic migraine, 26% reported side-effects after the first treatment and this declined to 11% with a second treatment. 9% reported a worsening of headache.
In general, adverse reactions occur within the first few days following injection and are not permanent or long-lasting.
Serious and/or immediate hypersensitivity reactions have been rarely reported. However, these can include anaphylaxis (severe allergic reaction), serum sickness, urticaria (hives), soft tissue oedema (fluid retention) and dyspnoea (breathlessness).
Side effects related to spread of toxin distant from the site of administration have been reported, sometimes resulting in death, which in some cases was associated with dysphagia (difficulty swallowing), pneumonia and/or significant weakness. Patients treated with therapeutic doses may experience exaggerated muscle weakness.
As with any injection, injury can occur. An injection could result in localised infection, pain, inflammation, tenderness, swelling, bleeding, bruising, etc. BOTOX may cause asthenia (lack of strength), muscle weakness, somnolence (drowsiness), dizziness and visual disturbance, which could affect driving and the operation of machinery. If there is a reaction, further injections of BOTOX should be discontinued. Patients or caregivers should be advised to seek immediate medical care if swallowing, speech or respiratory disorders arise.
The safety and effectiveness of BOTOX in the treatment of chronic migraine has not been demonstrated in children (however, chronic migraine is rare in children).
Contraindications