Muscle relaxants are prescribed after orthopedic, spinal, and some general surgeries when muscle spasms contribute to post-operative pain. They are effective but cause significant drowsiness and must be used carefully alongside opioid pain medications.
Common Muscle Relaxants After Surgery
Cyclobenzaprine (Flexeril): the most commonly prescribed muscle relaxant. Typical dose is 5 to 10 mg three times daily. Works best for acute muscle spasm relief in the first 2 to 3 weeks after surgery.
Methocarbamol (Robaxin): causes less drowsiness than cyclobenzaprine. Available OTC in some countries. Dose is typically 750 to 1,500 mg four times daily. May be preferred for patients who need to stay more alert.
Tizanidine (Zanaflex): works differently from cyclobenzaprine by acting on the central nervous system. Dose starts at 2 mg and can increase to 8 mg every 6 to 8 hours. Can lower blood pressure, so standing up slowly is important.
Diazepam (Valium): a benzodiazepine occasionally used short-term for severe muscle spasms. Carries a higher risk of dependence and is typically reserved for cases where other muscle relaxants are insufficient.
Side Effects and Safety
Drowsiness is the most common side effect of all muscle relaxants. Do not drive, operate machinery, or make important decisions while taking them.
Combining muscle relaxants with opioid pain medication multiplies the sedation effect. Take the lowest effective dose of each and never exceed prescribed amounts.
Alcohol combined with muscle relaxants can cause dangerous respiratory depression. Avoid alcohol completely during use.
Dry mouth, dizziness, and blurred vision are common with cyclobenzaprine. These effects are more pronounced in patients over 65.
Cyclobenzaprine should not be used for more than 2 to 3 weeks continuously. It is structurally similar to tricyclic antidepressants and can cause cardiac effects at high doses.
How to Use Muscle Relaxants Effectively
Take muscle relaxants at bedtime if you are only prescribed one dose per day. The drowsiness helps with sleep, and muscle spasms are often worst at night.
If prescribed three times daily, take the largest dose at bedtime and smaller doses during the day to minimize daytime sedation.
Muscle relaxants work best in combination with stretching, ice or heat, and gentle movement. Medication alone does not resolve the underlying muscle tension.
If spasms improve, reduce to bedtime-only dosing before stopping. Discuss the tapering plan with your provider.
Keep a pain and spasm diary to track whether the medication is helping. If spasms persist after 2 weeks, your provider may adjust the treatment approach.
When to Contact Your Provider
Excessive drowsiness that prevents you from eating, drinking, or doing basic daily activities.
Confusion, hallucinations, or agitation (rare but possible, especially in elderly patients or with high doses).
Difficulty breathing, especially if taking muscle relaxants with opioids.
Muscle spasms that worsen despite medication, which could indicate a nerve compression or other complication.
Urinary retention (inability to urinate), which can occur with cyclobenzaprine due to its anticholinergic effects.
Can I take a muscle relaxant and opioid at the same time?
They can be prescribed together, but the combination significantly increases drowsiness and the risk of respiratory depression. Take the lowest effective dose of each. Never take extra doses of either. Your surgeon prescribed this combination with specific doses for a reason, so follow the schedule exactly.
How long should I take muscle relaxants after surgery?
Most surgical muscle spasms resolve within 1 to 3 weeks. Cyclobenzaprine is FDA-labeled for no more than 2 to 3 weeks of continuous use. If you still need muscle relaxant therapy beyond 3 weeks, talk to your provider about alternative approaches like physical therapy or a different medication.
Are muscle relaxants addictive?
Cyclobenzaprine and methocarbamol have low addiction potential, though your body can develop tolerance with extended use. Diazepam (Valium) carries a real risk of physical dependence and should only be used short-term. Stopping any muscle relaxant after prolonged use should be done gradually.
For patients
Get a personalized care plan.
This guide provides general information. For instructions tailored to your specific procedure, ask your provider about QR Rx care plans.
These medication guides are for educational purposes only and do not replace medical advice. Always follow your healthcare provider's specific medication instructions.
