Botulinum Toxin Type A

Botulinum Toxin Type A

What is Botulinum Toxin Type A?

Botulinum toxin is a chemical from the organism that causes botulism. This sounds alarming but, in actuality, we would need to use 3,000 times as much as we do in order to give you botulism. Botulinum toxin forces muscles to relax by preventing the release of acetylcholine from nerve endings. It is this acetylcholine which activates the muscle, causing it to contract or tighten up. Without acetylcholine, the muscle cannot stay tight. Botulinum toxin injections are typically performed for muscle knots or “trigger points.” The botulinum toxin does not actually begin to work for one to two weeks, but many patients feel better in a few days just from the needle breaking up the muscle knot. Trigger points are thought to be very tight bands in muscles. When other measures, such as trigger point injections, fail to produce relaxation in the muscle knot, we consider botulinum toxin injections.

When is it time to do botulinum toxin injection?

Naturally, before botulinum toxin injections are tried, we always try to find what is causing the muscle knots. This can be anything from inflammation inside the spinal column to a disc problem, or serious illness that might cause muscle knots or trigger points. This needs to be investigated and ruled out before botulinum trigger point injections are performed. Very frequently after various traumas or injuries, people develop painful muscle knots, often in their shoulders, neck or under their scapulae. Trigger points can also develop in the low back, buttocks and thighs. Trigger points can occur in the upper arms and forearms. When a patient gets good relief from their muscle knot pain with a simple trigger point injection of numbing medicine, but the pain returns, that is felt to be an indication for botulinum toxin injection.

How is the injection performed?

Botulinum toxin injections are usually done in the office, similar to trigger point injections. The area over the painful trigger point is sterilely cleaned and a small gauge needle is used to inject the medicine into the trigger point.

What are the risks of botulinum toxin injection?

Happily, the risks of botulinum toxin are few. Typically, there are no real side effects from the botulinum toxin. It tends to act locally where it is injected and usually does not cause body-wide side effects. One effect of the botulinum toxin is that it can produce weakness in the muscle into which it is injected. This is usually not a problem. If used frequently, a patient can develop antibodies to the botulinum toxin and it will begin to lose its effectiveness. We also warn patients about bleeding, infection, and drug reaction, but these problems are extremely rare.

How long does a botulinum toxin injection last?

Botulinum toxin injections are relatively new, and all of the studies to give precise answers to these questions have not been performed. The effect of botulinum toxin on the acetylcholine produced by the nerve ending typically wears off in three to four months. Interestingly, in many patients we have seen the effect of the injections last considerably longer; however, we do not have adequate information to predict how long the injection will last if it is effective. Trigger points, or muscle knots, treated with botulinum toxin injection may return and repeat injection may be required. It would probably not be worth repeating the injection if it does not last at least three to four months.

Is the injection painful?

Yes and no. Botulinum toxin injections usually are not as painful as injections with numbing medicine. The muscle knot, however, can be very sensitive. For patients who have benefited from botulinum toxin injection, they typically report the pain of injection is worth the relief.

What will happen during and after the procedure?

You will probably be put into a gown and seated or positioned lying down. The trigger point areas to be injected are marked with a pen and then carefully cleaned. At that point, a cold spray is used to numb the skin, and the botulinum toxin mixed with normal saline, with or without numbing medicine, is injected. The whole process takes a few minutes. The injection site is bandaged and the patient is instructed to take it easy for the rest of the day, and to place ice or a cold pack on the injected areas for a few minutes several times a day for a day or two. A return office visit appointment will be made in four to eight weeks for follow up. The patient is encouraged to call at any time if they have any problems.


Botulinum toxin injections have proven to be a valuable tool in the battle against pain from painful muscle knots or trigger points. Typically, botulinum toxin injections are not performed unless the patient has already responded favorably, but only temporarily, to regular trigger point injections with numbing medicine. Before botulinum toxin injections are performed, every effort should be made to understand the cause of the muscle knots or trigger points, and any serious illness should be dealt with first. The main side effects of botulinum toxin are weakness and the development of antibodies if used excessively.