Muscle relaxant: what they do and when to use them

Muscle relaxants are medicines that ease muscle tightness, spasms, or spasticity. You might get them after a bad back strain, after surgery, or when a neurological condition causes tight, overactive muscles. They don’t cure the underlying problem but can help you move, sleep, and do rehab exercises more comfortably.

Common types and drugs

There are two main groups: central acting and peripheral acting. Central acting drugs work on the brain or spinal cord to reduce muscle tone. Examples include cyclobenzaprine (Flexeril), methocarbamol (Robaxin), carisoprodol (Soma) and tizanidine (Zanaflex). Baclofen and benzodiazepines like diazepam are used for spasticity from conditions such as multiple sclerosis or spinal cord injury. Peripheral acting drugs act directly on muscle tissue — dantrolene is one example used for severe spasticity or malignant hyperthermia.

Each drug has a different profile. Cyclobenzaprine often helps short-term back strains. Tizanidine can be useful for spasticity but may lower blood pressure. Baclofen is strong for spasticity but can cause weakness. Carisoprodol can be habit-forming and is controlled in some places.

When to pick a muscle relaxant

Ask yourself: is the goal short-term pain relief so you can move and do physical therapy, or long-term control of spasticity? For acute muscle spasm, doctors usually prescribe a short course (often 1–2 weeks) plus rest, heat, and stretching. For chronic spasticity, drugs like baclofen or tizanidine may be used under specialist care with careful dosing and monitoring.

Non-drug options matter. Physical therapy, targeted stretching, heat or cold, topical pain relievers, and strengthening exercises often reduce reliance on medicines. Try these alongside any prescribed drug, not instead of medical advice.

Side effects you should watch for include drowsiness, dizziness, dry mouth, constipation, low blood pressure, and coordination problems. Mixing a muscle relaxant with alcohol, opioids, or other sedatives raises the risk of dangerous breathing problems. Some drugs affect the liver or interact with other medicines — tell your clinician about all drugs you take.

Safety tips: start at the lowest dose, avoid driving or heavy machinery if you feel sleepy, don’t mix with alcohol, and follow your prescriber’s duration guidelines. Don’t stop certain meds abruptly (baclofen withdrawal can be serious). Call your provider if you get breathing trouble, severe weakness, confusion, high fever, or a rash.

Want to know which option suits you? Talk to your doctor or pharmacist. They’ll match the drug to your condition, other health issues, and the activities you need to do every day.