Benzodiazepines in the Treatment of Spinal Cord Injuries
Benzodiazepines represent a drug class used for treating multiple aspects of spinal cord injuries. It is not uncommon for patients with a SCI to experience multiple types of pain. Areas of musculoskeletal pain include the shoulder, wrists, and back, resulting from an acute or chronic injury to musculature and surrounding tissue. Diazepam is an available option for treatment of musculoskeletal pain. Due to the drug class’ addictive potential, it is not recommended for long term pain management. Benzodiazepines can also be prescribed to address spasticity on a short-term basis. Spasticity is estimated to affect 70% of individuals with a SCI, and is distinguished by hypertonicity, hyperreflexia, and painful spasms. Upper extremity spasticity may not impair functional abilities, however severe spasticity may require pharmacological intervention.
Diazepam specifically increases the inhibitory effect of GABA by binding to pre- and postsynaptic neurons found in the CNS promoting depression of the central nervous system Skeletal muscle relaxation is subsequently induced by the inhibition of afferent pathways in the spinal cord. Excessive depression of the CNS may lead to problematic side effects, which can be influenced by the pharmacokinetics of the drug.
Benzodiazepines have various modes of administration, specifically enterally or parenterally [PO, IM, IV, rectal]. Absorption rates vary based upon the route of administration; it is important to note the quickest administration route is thru IV. A quicker absorption rate may lead to faster onset of adverse effects. Benzodiazepines cause depression of the CNS and related side effects such as dizziness, drowsiness, and lethargy. Another potential side effect of Diazepam is the “hangover effect” which is caused from a half-life ranging from 20-50 hours in adults. Benzodiazepines also have a high affinity for developing physical dependence and drug tolerance.
Implications for Physical Therapy
Physical therapists must be cognizant of side effects, dependence, and tolerance in patients taking benzodiazepines. Orthostatic hypotension is a frequent complication in patients with a SCI. Patients can experience orthostatic hypotension when beginning a benzodiazepine regimen. If recurring dizziness occurs, a therapist may implement a fall prevention program. Additionally, therapists must continue to monitor pain levels and range of motion to ensure the drug is working. A vital portion of competent patient care is education. Patients need to be aware that withdrawal complications will occur if medication is abruptly discontinued. Constipation can be especially hazardous for those with a SCI. Drug-induced constipation can trigger autonomic dysreflexia in some spinal cord injury patients, a potential life-threatening complication, so careful monitoring is required. Physical therapists must implement other techniques to manage pain and spasticity as a primary treatment option or adjunct to medication. Therapists should also schedule around peak drug times to promote efficacious sessions where the patient is motivated to participate.
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