A child with spastic cerebral palsy is to receive botulin toxin. The nurse prepares the child for administration of this drug by which route?

Choice A rationale Oral administration of botulinum toxin is not effective for treating spasticity in cerebral palsy. The toxin, a neurotoxin that blocks acetylcholine release at the neuromuscular junction, would be rapidly inactivated by gastric acid and digestive enzymes in the gastrointestinal tract, preventing it from reaching the targeted spastic muscles. Choice B rationale Subcutaneous injection of botulinum toxin is not the correct route for treating focal spasticity. This route targets the layer beneath the skin and is often used for systemic absorption, but it does not adequately deliver the drug directly into the bulk of the affected, spastic muscles to achieve localized chemodenervation. Choice C rationale Botulinum toxin is administered via intramuscular injection directly into the specific muscles identified as being hypertonic or spastic. This localized injection allows the toxin to block the release of acetylcholine at the presynaptic terminals of the neuromuscular junction, thereby temporarily paralyzing or relaxing the targeted muscles for several months. Choice D rationale Intravenous infusion of botulinum toxin is not used for treating spasticity because this route would lead to systemic distribution. This would result in widespread muscle weakness or paralysis, which is an undesirable and potentially dangerous side effect, rather than the intended localized reduction in focal spasticity.