Botulinum Toxin in Pain Management

Botulinum toxin produces temporary skeletal muscle relaxation and is used in many treatments of clinical disorders because of its property. Here, we discuss the use of botulinum toxin in pain management.

It is a neurotoxic protein and is produced by Clostridium Botulinum. In painful muscle disorders, treatment can be very painful at times. Research has shown the effectiveness of botulin toxin, a neuromuscular blocking agent in the treatment and diagnosis of painful situations related to skeletal muscles. Botulinum toxin in pain management is being used for more than 20 years in the treatment of diseases associated with muscle contraction and tension.

The toxin which provides short-term skeleton muscle relief is known as Botulinum and is also useful in the medication of several medical disorders. There have been several instances in pain management where Botulinum toxin is used to produce an anodyne effect in the lessening overactive muscles. In recent times research workers are carrying the scrutiny of the Botulinum toxin which is used to lessen the pain in various patients suffering from arthritis, myofascial syndrome, neuropathic pains and headaches.¹

Research is being conducted to discover the use of botulinum toxin in pain management of initial headaches, shoulder bone disorder, cervical and myofascial pain syndrome.

Myofascial Pain Syndrome – Usefulness of the botulinum toxin has been seen when injected at appropriate places like the neck or shoulder of the patients. When the patient is injected with the specific toxin along with regular physiotherapy the effectiveness lasts for 1 to 3 months without any complication except for temporary headaches, lethargy and muscle pain.

Chronic Back Pain – When a patient is injected with 40 to 50 units of simple botulinum toxin in the areas around the spine, a remarkable decline is noted in the back pain of the patient.

Headaches – There is a notable and constant effect of botulinum toxin A on the patients suffering from migraines. Apart from migraines, it also has a progressive effect on cervicogenic headaches and post whiplash.

Arthralgia – Botulinum toxin A can be used to lessen the pain of different kinds of arthralgia as after combining with the nociceptors in the fiber C, it restrains the discharge of the pain signals such as CGRP, substance P and glutamate. The whole procedure leads to the lessening of the pain and sensitization.

Severe Pelvic Pain – It is noted through different researches that the injection of botulinum toxin A leads to the lessening of muscle tightening and acts as a pain reliever. Injection of the botulinum toxin A has also led to the improvement of the functioning and pain in vaginismus, vulvodynia, severe prostatitis, levator ani convulsion and interstitial cystitis.

Neuropathic Pain – Discharge of inflammation-causing factors such as adenosine, cytokines, serotonin, bradykinin, prostaglandins affects the neurotransmission. This kind of secretion increases the pain-causing sensations by the formation of interim neuropathic conditions. Researchers are conducting research works to find out whether the botulinum toxin A is effective in controlling the discharge of the neurotransmitters, in turn, lessening the pain. However, reports have shown the effectiveness of botulinum toxin A or B on patients suffering from neuropathy caused due to an injury in the spine, neuralgia, pain due to amputation of a limb and trigeminal neuralgia.

Studies have shown that botulinum toxin in pain management has proved efficacious in the treatment of headaches, migraine, chronic lumbar pain, and myofascial pain. It is well tolerated in the treatment of chronic pain disorders and has been able to reduce the use of analgesics.²

Botulinum toxin is used in the medication of several diseases and that may include strabismus, adductor spasmodic dysphonia, hemifacial spasm, bruxism, blepharospasm, cervix dystonia, dystonia, mandibular dystonia, uncontrolled contraction of the interior anal sphincter, detrusor muscle problem, paralysis, and stammering. Apart from the above-mentioned diseases, botulinum toxin is also used in various beauty medications, ptyalism, and hyperhidrosis and case of pain due to the damage of nerves, especially in hands and feet. The effectiveness of botulinum toxin in the mentioned diseases can be described through its reaction to the conduction of the cholinergic nerve.

The therapy includes injecting an appropriate amount of botulinum toxin in the patient. This partially stops the neural transmission for a particular period that in turn lessens the muscle tightening and production of glandular tissues. The primary work of the botulinum toxin is to make the alpha motoneurons non-adaptive, which instigate the fiber of the muscle.

While botulinum toxin in pain management proves to be effective, here is how it acts.

• It Disrupts the transfer of pain receptors
• Produces an indirect effect on pain processing pathways of CNS
• Blocks the release of neurotransmitters
• Affects the signaling pathways of the supporting cells.
• Stops the surface expression of the receptors

Proper patient selection, injection technique, and dosing are important to obtain the best results of botulinum toxin in pain management.³

The botulinum toxin takes 2 to 5 days to weaken the strength of the skeletal muscle after it is injected in the body of the patient and it takes another 2 weeks’ time to diminish it after which it gets better. The effect of the Botulinum toxin to lessen the skeletal muscle may continue for 3 to 4 months generally and the amount and time-span of denervation may depend on the dosage of the injection given to the patient. The withering of the muscles and changing of the fibers present in the muscle may seem to occur when the effect of the medicine injected is powerful. However, the reaction of the medicine seems to lessen after a period of 2 to 3 months. There are 2 ways in which local paralysis can help the person to get better and it includes a renewal of SNARE tissues or budding of the neurons.

After botulinum toxin injection, the strength of skeletal muscles weakens in 2-5 days. It gets minimized in 2 weeks and then the recovery starts. This effect keeps going on from 6 weeks to 6 months. The degree and period of denervation are influenced by the injection dose. Changes in muscular fiber are seen during its strong period. Then the effect decreases gradually after 2-3 months.

The use of botulinum toxin is best performed under medical supervision and medical advice must be followed.

The procedure and amount of dosage along with the number of times the dosage should be given to the patient differs from patient to patient depending on each one’s particular situation. In the case of injection of the Botulinum toxin in the deeper parts of the muscle, it is advisable to be done through the procedure of electromyography, electromyostimulation or radiograph. The amount and frequency of the dose of Botulinum toxin given to a patient is determined on the basis of certain factors which include the different types of diseases, which the particular patient has, weight, the type of its muscles, symptoms produced by the disorder and reaction caused to the patient due to its earlier injection. To lessen the unfavorable outcome occurring due to the injection of the Botulinum toxin it is advised by the doctors to use a low amount of the medicine to attain the desired result.

Side effects may be noted after the injection of the botulinum toxin in pain management. The most common ones include bruises, pain occurring in the area where the medicine is injected, and feebleness in the muscles. It may also cause certain other kind of after-effects like dryness of the mouth, tiredness, fever, headaches and ptosis which may become visible after a week or 2 of the injection given to the patient and tend to re-occur when a higher amount of the dose is given to the patient but it is, however, temporary in nature. Though it’s quite rare the injection of the botulinum toxin may also give rise to allergic response and injections given around the area of the neck or mouth may lead to dysphagia in patients. When botulinum toxin in pain management is used for neuropathic pain, minor complications like antibody formation and immune-related complications may be noted.⁴

While using botulinum toxin in pain management on a patient, certain measures should always be kept in mind. A person, before injecting the medicine should always check for any infection present at the place where the injection needs to be given, the presence of Lambert Eaton Myasthenia syndrome or whether there is any sign of the allergic response due to the injection of the medicine. Patients with Amyotrophic Lateral Sclerosis disease, neuromuscular junction disease or the ones who are on some kind of drugs to control the conduction of the neuromuscular junction disease should be more cautious regarding themselves.

Primarily, the dosage should be set based on the evaluation of certain factors to minimize the side effects and complications which may occur. These factors may include the previous injection, health, age, muscle type, weight, and current health condition.

• It is always recommended to take the minimum amount needed of botulinum toxin in pain management to prevent adverse side effects and complications.
• If there is an infection on the injection site or allergy to the medication, the botulinum toxin should not be used.
• Its use is also prohibited in pregnant mothers as it can have an adverse effect and children of age less than 12 years.
• Care should be taken if a patient is having neuron disease, taking those type of medications which may hinder with neuromuscular conduction.

The botulinum toxin can be used to treat various types of chronic pain or pain management. Botulinum toxin in pain management has proved to be an effective way of treatment, which also gives time for other conservative treatments to act. The cost of botulinum toxin in pain management can be slightly expensive but compared to other medications there are fewer complications or side-effects connected to it which the patient may or may not have to suffer from. The effect of the treatment can be maintained for 3-4 months.

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