T. J. is a 25-year-old male who was involved in a motorcycle accident 4 weeks ago and transferred to an inpatient rehabilitation facility yesterday. He is scheduled for transfer training in the open gym immediately after breakfast today. As a result of the accident, T. J. has a stable spinal cord injury (SCI) at the T10 neurological level. The patient has no cardiovascular dysfunction. He is currently taking drugs to reduce spasticity, including tolterodine to reduce neurogenic detrusor overactivity (spastic bladder). The therapist and patient begin with a sliding board transfer from the wheelchair to the plinth. The patient urinates involuntarily during his initial attempt with the sliding board activities. The patient is embarrassed and states that this happened before when he attempted to sit up and reposition himself with his hands. The patient requests that this morning’s rehabilitation session be terminated. In the afternoon, T.J. does not want to come to the gym because he is concerned that the same problem will occur.
This chapter covers drugs that either enhance or inhibit the actions of cholinergic transmission. Cholinomimetics amplify cholinergic transmission and have the potential to improve or inhibit the rehabilitation process. Prescriptions for either direct-acting or indirect-acting cholinomimetics may be prescribed for glaucoma, hypotonic bladder function, myasthenia gravis, or Alzheimer’s disease. In individuals with Alzheimer’s dementia, scheduling rehabilitation when these drugs are at their maximal plasma level may enhance functional or cognitive activities and assist the therapist in providing a positive outcome. In contrast, many patients may also be self-medicating with nicotine (a direct-acting agonist at nicotinic receptors) via inhalation or buccal (ie, smoking or dipping) absorption. These patients may experience various adverse sympathetic or parasympathetic responses based on other comorbidities. The therapist should encourage these patients to abstain from these activities prior to rehabilitation interventions (or permanently, if possible).
The second half of the chapter covers muscarinic and nicotinic antagonists that inhibit cholinergic transmission. Muscarinic antagonists may be prescribed for patients with spastic bladder and incontinence, parkinsonism, or pulmonary dysfunction. For individuals with spastic bladder and incontinence due to SCI, inadvertent voiding may be reduced by scheduling rehabilitation interventions during peak plasma levels of the drug. During sustained periods of exertion, hyperthermia may occur due to the inhibition of eccrine sweat glands by antimuscarinic agents. The clinical application for antimuscarinics in the treatment of parkinsonism and pulmonary dysfunction are discussed in Chapters 17 and 35, respectively. Cholinergic antagonists that act at nicotinic acetylcholine receptors in skeletal muscle are commonly used in patients undergoing major surgery requiring mechanical ventilation. In these patients, normal musculoskeletal function returns following elimination of the drug. If possible, the therapist should establish and review treatment plans with patients prior to surgery when cognitive and musculoskeletal function is higher than immediately following surgery.
When synaptic transmission depends on acetylcholine as the ...