Spasticity
Botulinum Toxin Type A FAQ
Can oral or intrathecal antispastic medications be used in combination with botulinum toxin type A?
Yes. Oral medications and intrathecal baclofen provide global tone reduction, whereas BTX-A injections can provide graded focal relief in selected muscles. BTX-A and antispastic agents do not have drug-drug interactions. The appropriateness of any spasticity therapy relies on its efficacy in meeting the goals of patients and caregivers. The treatment plan should reflect the patient's current clinical status on antispastic medication and the therapeutic goals for BTX-A therapy, including target muscles and dosing levels. The use of BTX-A, for example, may be beneficial for hand, arm or neck problems in certain patients using intrathecal baclofen for leg spasticity.
Can botulinum toxin type A and phenol or alcohol neurolysis therapies be combined?
Yes. The primary reason for combining BTX-A with phenol or alcohol neurolysis therapies is to avoid resistance by remaining under the maximum dose per visit. The decision to combine therapies usually depends on the location and number of target muscles involved. If both lower and upper extremities are to be injected, the combination of BTX-A and phenol may be warranted. Although there are certain difficulties in using phenol or alcohol neurolysis, they provide inexpensive, long-term chemodenervation options for some patients.
Is botulinum toxin type A useful in treating pain?
Some patients with painful spasms or contracture report a reduction in pain after injection with BTX-A.
What are the chances of accidental overdose from botulinum toxin type A injections?
Accidental overdose during spasticity therapy is highly improbable, since dozens more vials of BTX-A than are used therapeutically would need to be injected. In the event of an overdose, the medical information line maintained by Allergan can be contacted at (800) 433-8871 or (714) 246-5954.
How is botulinum toxin type A injected?
BTX-A is injected in the same manner as local anesthetics. A 23-gauge to 26-gauge needle is placed into the target muscle. Targeting is confirmed by palpation in larger muscles, or by EMG or ES monitoring in small or deep muscle groups. Ultrasound, fluoroscopy or CT may also be used.
Hollow electromyography needles are often used, decreasing the number of needle sticks and increasing the accuracy of needle placement. Local anesthetic cream, general anesthesia, or sedation may be necessary, particularly for some children. Following preparation of the area to be injected, sterile gloves and a "no-touch" skin entry site technique are used.
How often can botulinum toxin type A injections be given?
BTX-A injections are usually needed at 3 to 6 month intervals to maintain therapeutic benefit, depending on the location and severity of spasticity. Reinjections should not be given any sooner than 3 months after the last injections to decrease the possibility antibody formation.
Can the risk of antibody formation be reduced?
Yes. Repeated, high dose injections are far more likely to result in antibody formation than are less frequently repeated, low dose injections. Physicians should, therefore, use the smallest amount of BTX-A necessary to achieve therapeutic benefit and extend the interval between treatment sessions as long as possible.
Antibody assays can be obtained through Northview Pacific Laboratories, 2800 7th Street, Berkeley, CA. 94710, (510) 548-8440.
Can botulinum toxin type A booster injections be given without causing resistance?
It depends. When the amount injected totals the maximum of 400 units, due to the risk of producing resistance, further injections should not be given before three months after the last BTX-A treatment. The interval between treatments to improve clinical objectives should be extended as long as possible. The smallest amount of BTX-A necessary to achieve the desired effect is suggested. Frequent injections do increase the chances of antibody formation.
