Taking Flexeril (generic name cyclobenzaprine) for muscle spasms? Good to know what side effects are common, which ones are serious, and simple steps to reduce risk. This page gives clear, practical advice so you can use the drug safely and spot trouble early.
The most common issues are drowsiness, dizziness, dry mouth, and fatigue. These happen because Flexeril works on the central nervous system. You may also notice blurred vision, constipation, or mild headache. Most people find these settle within a few days as the body adjusts.
Less common but possible effects include confusion, urinary retention (trouble peeing), and lightheadedness when standing up. Older adults often feel stronger drowsiness and are at higher risk for falls. If you already take medications that make you sleepy, the effect can be much worse.
Call your doctor or get emergency help if you experience fast or irregular heartbeat, fainting, severe dizziness, severe allergic reaction (hives, swelling, trouble breathing), or signs of serotonin syndrome: high fever, agitation, rapid heartbeat, tremor, or stiff muscles. Serotonin syndrome is rare but can occur if Flexeril is combined with certain antidepressants.
Avoid Flexeril if you recently used MAO inhibitors (you need to wait at least 14 days). Also use caution with SSRIs, SNRIs, tricyclic antidepressants, and other drugs that affect serotonin or slow heart rate. Don’t mix Flexeril with alcohol or sedatives—doing so amplifies drowsiness and breathing problems.
Typical dosing is 5–10 mg, usually at bedtime or as directed by your doctor. Do not increase dose without medical advice. Pregnant or breastfeeding people should check with their clinician before using Flexeril—your provider will weigh benefits and risks.
If you suspect an overdose (extreme drowsiness, irregular heartbeat, seizures), call emergency services right away.
Simple tips to reduce side effects: take the lowest effective dose, avoid alcohol and heavy machinery while you’re adjusting, stand up slowly to prevent lightheadedness, chew sugar-free gum or sip water for dry mouth, and ask your doctor about switching to an alternative muscle relaxant if side effects are severe.
Alternatives include tizanidine, metaxalone, and baclofen, but each has its own risks. Talk with your provider about your medical history, other meds, and which option fits you best.
If you’re unsure whether a symptom is from Flexeril, call your pharmacist or doctor. Keep a short list of your medicines and bring it to appointments so your provider can check for interactions. Staying informed helps you get the pain relief you need without unnecessary risk.
