chlorzoxazone
Chlorzoxazone, also known by the now discontinued brand name Lorzone, is a muscle relaxant used to treat sudden muscle pain in adults, along with rest and physical therapy. It's thought to work by calming nerve signals that cause muscles to tighten or cramp. The medication comes in tablet form, and you'll typically take a dose by mouth three or four times a day. Though chlorzoxazone is generally well tolerated, side effects can include drowsiness, dizziness, and feeling lightheaded.
What is Chlorzoxazone?
What is Chlorzoxazone used for?
- Muscle pain and discomfort caused by acute (short-term) conditions
How Chlorzoxazone works
Chlorzoxazone is a muscle relaxant. Experts aren't exactly sure how it works, but it doesn't seem to act directly on the muscles. It's thought to help by calming the nerves that make your muscles tighten or cramp, which can reduce pain and discomfort.
Drug facts
Side effects of Chlorzoxazone
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
- Drowsiness
- Dizziness
- Feeling lightheaded
- General discomfort or feeling ill
Less Common Side Effects
- Rash or other skin reaction
- Discolored urine
- Overstimulation
Chlorzoxazone serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Liver damage: dark urine, yellowing of the skin or eyes, upper right stomach pain, loss of appetite
- Severe allergic reaction: hives, rash, redness, itching, trouble breathing
The following Chlorzoxazone side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Rare
Bloody or black, tarry stools
clay-colored stools
dark urine
decreased appetite
difficulty swallowing
dizziness
fast heartbeat
headache
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
loss of appetite
puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
severe stomach pain
shortness of breath
skin rash
swelling of the feet or lower legs
tightness in the chest
unusual tiredness or weakness
vomiting of blood or material that looks like coffee grounds
yellow eyes or skin
Get emergency help immediately if any of the following symptoms of overdose occur:
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Rare
Bruising
large, flat, blue, or purplish patches in the skin
small red or purple spots on the skin
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
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Pros and cons of Chlorzoxazone
Pros
- Relieves muscle pain and spasms
- Not a controlled substance
- Usually well tolerated
Cons
- Can cause dizziness and drowsiness
- Needs to be taken multiple times a day
- Interacts with alcohol and other medications that cause sleepiness
Pharmacist tips for Chlorzoxazone
- Chlorzoxazone is usually meant for short-term muscle pain. Don’t use it longer than your prescriber tells you to.
- Take chlorzoxazone at the same times each day, and try to space your doses evenly. As your pain improves, your prescriber might lower your dose.
- Keep resting your muscles and doing physical therapy if recommended. Chlorzoxazone works best when used along with other treatments, not as a replacement.
- Rarely, chlorzoxazone can change the color of your urine. This is harmless and goes away after you stop the medication.
- Chlorzoxazone can cause drowsiness or dizziness. Don’t drive or use heavy machines until you know how it affects you.
- Avoid alcohol while taking chlorzoxazone as it can make side effects like drowsiness and dizziness worse.
- Watch for signs of liver problems while taking chlorzoxazone. Stop taking it and call your prescriber if you feel nauseous, tired, have dark urine, yellowing skin or eyes, or upper right stomach pain.
- Talk to your prescriber before using chlorzoxazone if you’re pregnant or planning to become pregnant. It’s not known if this medication is safe during pregnancy, so it should only be used if your prescriber believes the benefits outweigh the risks.
Common questions about Chlorzoxazone
Always talk with your healthcare team before taking new medications after a gastric bypass surgery. A research study found that taking chlorzoxazone after this type of surgery can cause your body to absorb more of the medication than usual. This might happen because the surgery could change how your body breaks down certain medications. To lower your chance of side effects or other problems, ask your prescriber if chlorzoxazone is safe for you to take after surgery.
No, chlorzoxazone isn't a controlled substance. This means it doesn't have a high risk of misuse and addiction.
Chlorzoxazone can interact with many other medications, so it's important to make sure your prescriber and pharmacist have a full list of your medications before you start. Be extra careful if you're taking other medications that can make you sleepy, especially if you need to drive or do anything that requires focus. Combining these medications can be dangerous.
Drinking alcohol while taking chlorzoxazone can make side effects like dizziness and drowsiness worse. This could put you at risk if you need to drive or do anything that requires concentration. To stay safe, it’s best to avoid alcohol while using chlorzoxazone.
Yes, you can usually take chlorzoxazone with ibuprofen. These two medications work in different ways —ibuprofen helps reduce inflammation and pain, while chlorzoxazone is a muscle relaxant that helps calm muscle spasms. In fact, they are often prescribed together for muscle pain. But you should still check with your prescriber, especially if you have other health conditions or are taking other medications that could interact.
Chlorzoxazone starts to show up in the blood within 30 minutes and reaches its highest levels around 1 to 2 hours after taking it. But pain relief can vary from person to person. Some people might feel better quickly, while others might take a little longer depending on their health, condition, or other medications they’re taking. If you’re not noticing improvement after a few doses, it’s a good idea to check in with your prescriber.
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Risks and warnings for Chlorzoxazone
Chlorzoxazone can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Liver damage
Although rare, serious liver damage (including life-threatening cases) has been reported with chlorzoxazone. Stop taking it and contact your prescriber right away if you notice fever, rash, loss of appetite, nausea, vomiting, tiredness, upper right stomach pain, dark urine, or yellowing of your skin or eyes. Your prescriber might also check your liver enzymes during treatment.
Interaction with alcohol and other medications
- Risk factors: Drinking alcohol | Taking medications that cause sleepiness
Don’t drink alcohol or take medications that make you sleepy — like sleep aids, anxiety medications, or strong painkillers — while taking chlorzoxazone unless your prescriber says it’s okay. Taking them together can make you extra sleepy, dizzy, or even slow your breathing, which can be dangerous. Always check with your prescriber or pharmacist before combining medications.
Allergic reactions
Use chlorzoxazone carefully if you’ve ever had an allergic reaction to medications. If you notice itching, redness, or hives, stop taking the medication and call your prescriber right away.
Chlorzoxazone dosage
Interactions between Chlorzoxazone and other drugs
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Alfentanil
- Alprazolam
- Amobarbital
- Aprobarbital
- Benzhydrocodone
- Bromazepam
- Buprenorphine
- Butabarbital
- Butalbital
- Butorphanol
- Calcium Oxybate
- Cannabidiol
- Carisoprodol
- Cetirizine
- Chloral Hydrate
- Chlordiazepoxide
- Clobazam
- Clonazepam
- Clorazepate
- Codeine
- Dantrolene
- Diazepam
- Dihydrocodeine
- Doxylamine
- Eliglustat
- Esketamine
- Estazolam
- Ethchlorvynol
- Fentanyl
- Flibanserin
- Flunitrazepam
- Flurazepam
- Gabapentin
- Gabapentin Enacarbil
- Halazepam
- Hydrocodone
- Hydromorphone
- Ketamine
- Ketazolam
- Lemborexant
- Levocetirizine
- Levorphanol
- Lofexidine
- Lorazepam
- Lormetazepam
- Loxapine
- Magnesium Oxybate
- Medazepam
- Meperidine
- Mephenesin
- Mephobarbital
- Meprobamate
- Metaxalone
- Methadone
- Methocarbamol
- Methohexital
- Metoclopramide
- Midazolam
- Morphine
- Morphine Sulfate Liposome
- Nalbuphine
- Nitrazepam
- Oxazepam
- Oxycodone
- Oxymorphone
- Pentazocine
- Pentobarbital
- Periciazine
- Phenobarbital
- Potassium Oxybate
- Prazepam
- Pregabalin
- Primidone
- Quazepam
- Remifentanil
- Remimazolam
- Scopolamine
- Secobarbital
- Sodium Oxybate
- Sufentanil
- Tapentadol
- Temazepam
- Thiopental
- Tramadol
- Triazolam
- Zolpidem
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- St John's Wort
How much does Chlorzoxazone cost?
$29.44
What are alternatives to Chlorzoxazone?
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