What is BOTOX®?

BOTOX® is a brand name for a purified form of botulinum toxin type A, used by injection to treat medical conditions such as facial or other muscle spasms, and more recently for cosmetic purposes to reduce frown and wrinkle lines on the face. Another brand, Dysport®, is also used for medical conditions but is licensed for fewer cosmetic uses. Anyone planning to have botulinum type A injections should discuss with their doctor the possible side effects versus potential benefits. Injections should be given by a medical professional trained in its use.

What is botulinum toxin type A?

Botulinum toxin type A is a chemical toxin produced by Clostridium botulinum bacteria. Although this is the same toxin that causes botulism - a type of infection that can result in life-threatening muscle paralysis - BOTOX® is safe to use as an injectable medicine because it is used in such small quantities and injected directly into specific sites. (As with any medicine, some people may experience side effects.) Its use as a cosmetic treatment was only discovered when people using it to treat facial muscle spasms noticed an improvement in their wrinkles.

How does it work?

BOTOX® works by blocking the release of a neurotransmitter (a chemical messenger) known as acetylcholine from nerve cells. Acetylcholine normally transmits nerve impulses to muscle cells. Without acetylcholine, the affected nerve is unable to send a signal to the muscle it supplies, resulting in a weakened or paralysed muscle. The effect of BOTOX® injection is restricted to the area being treated, and because the nerve fibres usually regenerate after a couple of months, the effect is only temporary.

What is it used for?

Botulinum toxin type A is used to treat medical conditions such as:

• blepharospasm (twitching or spasm of the eyelid);
• cervical dystonia, or spasmodic torticollis (a type of muscle spasm in the neck);
• facial or other localised muscle spasms;
• muscle spasticity due to cerebral palsy; and
• strabismus (a condition where the eyes are not properly aligned).

Botulinum toxin type A can also be injected into the skin to block the action of the nerves that control your sweat glands. It can be used in this way to treat excessive localised sweating (hyperhidrosis), especially severe underarm sweating.

BOTOX® can also be used to help prevent migraine headaches in certain people with chronic migraine.

BOTOX® injections are approved for the cosmetic treatment of vertical frown lines (also called 'glabellar lines' - lines between the eyebrows that are caused by the muscles that contract when you frown, squint or concentrate), horizontal forehead lines, and lines radiating from the corners of the eyes (crow's feet). Another brand of botulinum toxin type A (Dysport®), is approved for the treatment of moderate to severe vertical frown lines between the eyebrows.

How is BOTOX® injection used to treat wrinkles?

BOTOX® injections can be used to weaken or paralyse some of the facial muscles that pull on your skin and cause wrinkles, allowing the skin to flatten out. About two to seven days after the injections, the lines and wrinkles that are normally caused by certain facial expressions start to disappear. Because BOTOX® therapy targets specific, individual muscles, the ability to form most facial expressions should not be affected.

How long does the effect last?

The improvement in the appearance of your wrinkles usually lasts for three to six months, and repeated injections are required to maintain the effect. With continued use, the effects may start to last longer. A small number of people develop neutralising antibodies to BOTOX® injections after repeated therapy, which results in the treatment no longer being effective.

Is BOTOX® therapy safe?

BOTOX® injections are relatively safe when administered by a medical professional who is trained in its use. As with all treatments, there are some side effects associated with its use, but most of these are mild and temporary. Pain, tenderness and bruising may be associated with the injection, and some people have reported a slight headache after treatment. Nausea and a flu-like syndrome are also rarely reported. There is only a small risk of significant side effects from BOTOX® treatment, such as a drooping eyelid (which usually only lasts a few days, but can last longer).

BOTOX® injections should not be used in women who are pregnant or breast-feeding.

It is important to remember that all medical procedures carry risks as well as benefits, and you need to discuss these with your doctor.

More information

• Talk to your doctor
• See the NZ Medsafe website for Consumer Medicine Information [enter trade (brand) name on form and hit Search, for a pdf file about BOTOX®].

Related topics

Side effects of medicines

Original material provided by myDr, reviewed November 2011. Edited by everybody, March 2012.