Comparison of baclofen and tizanidine adverse effects among community-dwelling adults over the age of 50: a systematic review

Purpose Antispasmotics used for muscle spasticity have adverse effects such as bradycardia, hypotension, and altered mental status that can be concerning when used in geriatric patients due to possible fall outcomes. The purpose of this research is to discern the true risks of antispasmotics in older adults to encourage positive patient outcomes. Methods A literature search was performed using Web Of Science, Scopus, Embase, and Pubmed. Studies included were patients greater than 50 years-old on oral baclofen or tizanidine in a community dwelling. The FDA Adverse Event Reporting System (FAERS) was searched with these same criteria. Studies excluded were not available in English, focused on animals, included subjects less than 50 years old or patients receiving non-oral baclofen, or hospitalized patients. Results The literature search rendered seven articles that met inclusion criteria. Five articles contained baclofen-related side effects such as drowsiness, dyskinesia, sleep apnea, somnolence, and hypotension. One case report showed a positive correlation between tizanidine and bradycardia requiring transvenous pacing. Another case report was found searching abstracts, relating tizanidine to hypotension. The FAERS database rendered 305 tizanidine and 496 baclofen reports of different adverse effects. Conclusions No studies directly evaluated the comparison of antispasmotics and other mediations known to cause falls or confusion in older, community-dwelling adults. FAERS database show possible association between antispasmotics and adverse effects that could contribute to falls. Future research comparing antispasmotics and other medications known to cause falls could determine whether antispasmotics are truly a safer alternative in older adults.