Muscle Relaxant Side Effects
Muscle relaxants are a diverse group of medications that have an overall sedative effect and can be used for discomfort associated with muscle spasms. These agents work by lessening the tension in stiff muscles, which reduces pain and discomfort. They are thought to work by suppressing the central nervous system. Muscle relaxants are sometimes prescribed for patients with back pain and for symptoms of fibromyalgia.
Baclofen, in particular, may be used for treating multiple sclerosis (abnormal hardening of body tissue) and stabbing nerve pain. Chlorzoxazone is used for the relief of discomfort from acute, painful, musculoskeletal conditions. Soma relaxes muscles and eases ache and stiffness caused by acute muscle and bone problems. Flexeril eases stiffness and pain from muscle spasms, while Dantrolene helps control chronic spasticity, including symptoms related to spinal injuries (National Center of Biotechnology Information [NCBI]
“Comparing Muscle Relaxants, Dec 2007).
Common Side Effects
Possible side effects of muscle relaxants include: drowsiness or dizziness, dry mouth, possible addiction, and urinary retention. Other possible side effects include tremor, irritability, agitation, and headache. Serious side effects for some patients include hives, serious allergic reactions, fainting, low blood pressure, and seizures (National Center of Biotechnology Information [NCBI]
“Comparing Muscle Relaxants,” Dec 2007).
Understand Your Risks with the Rxight® Genetic Test
As part of the Rxight® pharmacogenetic testing program, our lab measures your body’s genetically modulated metabolism of hundreds of prescription and over-the-counter pharmaceutical agents in nearly 50 drug classes, including muscle relaxants. It’s safe and simple – all we need is a cheek swab of your DNA testing is complete, each patient receives a Personalized Medication Review® interpreted by a pharmacist trained PGx testing. PGx testing thus save you from the potential adverse effects, allowing your prescriber to tailor your medication dosage to your unique genetics to diminish potentially dangerous adverse reactions.
How Does Pharmacogenetic Testing Work?
Pharmacogenetic testing analyzes variations in the genes that impact how they encode enzymes responsible for metabolizing drugs. Typically, in the absence of genetic testing, the traditional way for providers to determine your drug adverse reactions is to use the trial and error approach to prescribing medications. However, with PGx testing, individual genetic variation in drug metabolism genes can predict how a patient will respond to a pharmacological agent – depending on how quickly they are able to metabolize a particular pharmacological agent.
So-called “slow metabolizers” are at higher risk for toxicity and medication side effects. “Rapid metabolizers” and “ultra-rapid metabolizers” are at risk for the medication not being effective at standard doses. Variation in any of these genes means that the enzyme made from the genetic instructions is also altered, resulting in side effects or inefficacy. Pharmacogenetic testing helps clinicians select medications and doses associated with better therapeutic value and fewer side effects – rather than relying on a potentially protracted and deleterious trial and error approach.
Contributors to this Article:
Michael Sapko, MD, PhD; Deborah Kallick, PhD, Medicinal Chemistry