Botox Injections for Pain Control: Know the Risks and Benefits

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Botox Injections for Pain Control

The idea of purposefully paralyzing a nerve seems frightening to most people. Yet for those with severe, chronic pain, deadening muscle activity promises a means to regain control over their condition. Botox, the brand name of a preparation of botulinum toxin type A, blocks the electrical transmission of specific nerves that overstimulate muscle activity and cause painful spasms.


Botox, manufactured by Allergan, is approved by the U.S. Food and Drug Administration for controlling the pain associated with specific medical conditions that cause muscle spasms. Botox injections can treat pain associated with cervical dystonia, which is a condition causing severe spasms in shoulder and neck muscles, arm spasticity, and for the eye conditions blepharospasm, or a spasm of the upper eyelid muscles, and strabismus. It is also used for treatment of migraines and other musculoskeletal pain caused by spasms.


Botox is derived from the potentially fatal toxin produced by the bacterium Clostridium botulinum. In low doses, the toxin can be injected into specific muscles to produce a controlled temporary paralysis. Botox blocks the release of the chemical neurotransmitter acetylcholine from nerve endings. An excess of acetylcholine overstimulates the muscles, resulting in painful contractions and spasms.

Blocking the nerve impulses is a three-part process. First, the toxin binds to the nerve terminal, the place where the nerve attaches to the muscle surface. Next, the nerve takes up the toxin and forms a vesicle, a small sac filled with fluid. The toxin releases its acetylcholine-blocking properties into the vesicle. Lastly, the toxin blocks a specific protein in the cell necessary to the release of acetylcholine. The nerve endings blocked by the toxin are unable to release the neurotransmitter that overexcites muscles and stimulates spasms. The toxin is specific and does not affect other electrical impulses from the nerve endings.


By blocking the release of acetylcholine, Botox removes the cause of muscle overactivity and reduces chronic severe pain. Botox pain injections are specific and the temporary paralysis of the neurotransmitter occurs only in the targeted muscle. The effect lasts up to 3 months before the nerve endings regenerate and the pain returns.

Side Effects

Botox injections for pain control provide long-term relief, but they do not remove the source of pain. Injections must be repeated approximately every 3 months when the pain returns. Botox can lose effectiveness if the pattern of muscle spasms changes. In those cases, the physician must adjust the injection site to target the newly activated muscles. Continuous use of Botox may stimulate the body to develop antibodies to the toxin. Using the lowest effective dose and delaying injections as long as possible can help reduce this risk.

The most commonly reported side effects associated with Botox injections include difficulty swallowing, upper respiratory infections, neck pain, headaches, drooping eyelids, and eye dryness if used near the eye area. Other side effects may include nausea and vomiting, abdominal pain, facial paralysis, malaise, and localized numbness. After an injection, the injection site may be sore.

In some cases, the toxin migrates beyond the muscle into which it was originally injected. Seek immediate medical attention if you experience difficulty swallowing or breathing. These side effects may be severe or fatal.


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