Baclofen-induced cough suppression in cervical spinal cord injury

Dicpinigaitis PV, Grimm DR, Lesser M. Baclofen-induced cough suppression in cervical spinal cord injury. Arch Phys Med Rehabil 2000;81:921-3. Objective: To determine the effect of the GABA-agonist baclofen on cough reflex sensitivity in subjects with cervical spinal cord injury (C-SCI). Baclofen has been shown to inhibit the cough reflex in able-bodied volunteers. Design: Prospective, nonrandomized control trial. Setting: Veterans Affairs medical center with large outpatient SCI population. Participants: Twelve adult males (11 outpatients) with C-SCI chronically maintained on oral baclofen for the treatment of muscle spasm. Intervention: Subjects underwent cough challenge testing with inhaled capsaicin. The concentrations (μM) of capsaicin inducing 2 or more (C2) and 5 or more (C5) coughs were determined. Mean values for log C2 and log C5 were compared with a control group of outpatients with C-SCI not receiving baclofen. Results: Subjects treated with baclofen had a significantly higher cough threshold (diminished cough reflex sensitivity) than control subjects. Mean (± standard error of the mean) values for log C2 in study subjects and controls were 1.28 ±.16 and.65 ±.15, respectively (p =.009). Mean values for log C5 in subjects receiving baclofen and in control subjects were 2.20 ±.22 and 1.43 ±.23, respectively (p =.024). Subjects and controls did not differ in terms of age, spirometric parameters, or duration of injury. Conclusions: The results suggest that chronic therapy with baclofen diminishes cough reflex sensitivity in subjects with C-SCI. The clinical significance of this finding remains to be elucidated. © 2000 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation