Treatment with botulinum toxins may weaken neck muscles that serve as accessory muscles of ventilation. This may result in a critical loss of breathing capacity in patients with respiratory disorders who may have become dependent upon these accessory muscles. There have been postmarketing reports of serious breathing difficulties, including respiratory failure.
Co-administration of BOTOX® or other agents interfering with neuromuscular transmission (eg, aminoglycosides, curare-like compounds) should only be performed with caution as the effect of the toxin may be potentiated. Use of anticholinergic drugs after administration of BOTOX® may potentiate systemic anticholinergic effects. The effect of administering different botulinum neurotoxin products at the same time or within several months of each other is unknown. Excessive neuromuscular weakness may be exacerbated by administration of another botulinum toxin prior to the resolution of the effects of a previously administered botulinum toxin. Excessive weakness may also be exaggerated by administration of a muscle relaxant before or after administration of BOTOX®.
The safety and efficacy of onabotulinumtoxinA for CM was demonstrated in the pivotal phase III Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) trial. In this trial, patients were treated every 12 weeks whether or not their headaches had returned to baseline levels and the primary outcome period was after two treatment cycles. At baseline, these patients had more than 19 headache days, and after two treatment cycles, their headaches had been reduced by 8 to 9 days per 28 days. The responder rate analysis of the study population shows that about 25% of patients improved by 75% in terms of a reduction of migraine days. In my practice, I usually do three cycles 12 weeks apart, and only if there is no change in headache frequency after this, do I change treatments. In the pivotal trials, the first statistical separation from placebo occurred in the first 4 weeks. There is a small subgroup of patients who fail to respond to the first two treatments and only start to respond after the third treatment.4-10
“I see a lot of patients who come in from sun damage, or who have creases in their foreheads, more lines around the sides of their mouths, crow's feet, and wrinkles on the side of their nose,” Shah says. “At this age, a dermatologist can inject Botox in the right places to help train a person’s face to no longer fall into that habit, which can help decrease the odds that they’ll develop permanent wrinkles in those spots later on.”
If the musculature of the oropharynx and esophagus are affected, aspiration may occur which may lead to development of aspira tion pneumonia. If the respiratory muscles become paralyzed or sufficiently weakened, intubation and assisted respiration may be necessary until recovery takes place. Supportive care could involve the need for a tracheostomy and/or prolonged mechanical ventilation, in addition to other general supportive care.
After an exam by a therapist and doctor, botulinum toxin for focal relief of muscle spasticity can be advised as the best way to address a child's functional problems. The problem muscle groups are identified, and goals for that child are discussed. Then the injection of botulinum toxin can be done if there are no permanent contractures of the muscle groups.
The number of headache days determines whether the patient has episodic migraine (EM) (14 or fewer headache days a month) or CM (more than 15 days of headache a month). The best method of determining the actual number of headache days is to subtract this from the number of completely headache-free days in a month. If headache is present on more than half the days in the month, and there are migraine features on at least 8 days a month, the condition is termed CM. The migraine features only have to be present on 8 days out of the month and not on every headache day. The other headache days in this condition are considered to be milder forms of migraine, and they do not have all the typical migraine features. If headache is present on fewer than 15 days a month, this is referred to as EM. EM can transform to CM over time. If analgesics are used on 10 or more days per month, this can lead to a transformation to CM. The patient’s headache pattern over a 12-month period should be determined, and during this time, there should be at least 3 months with 15 headache days; 8 of these days should meet migraine criteria.1-3