Clinical data | |
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Trade names | Lorzone, Paraflex, Muscol |
AHFS/Drugs.com | Monograph |
MedlinePlus | a682577 |
License data | |
Routes of administration | By mouth |
Drug class | Skeletal muscle relaxants |
ATC code | |
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Pharmacokinetic data | |
Bioavailability | Well absorbed |
Protein binding | 13–18% |
Metabolism | Hepatic |
Elimination half-life | 1.1 hours |
Duration of action | 3–4 hours |
Excretion | urine (<1%) |
Identifiers | |
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CAS Number | |
PubChem CID | |
IUPHAR/BPS | |
DrugBank | |
ChemSpider | |
UNII | |
KEGG | |
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ChEMBL | |
CompTox Dashboard (EPA) | |
ECHA InfoCard | 100.002.186 |
Chemical and physical data | |
Formula | C7H4ClNO2 |
Molar mass | 169.56 g·mol−1 |
3D model (JSmol) | |
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Chlorzoxazone (INN) is a centrally acting muscle relaxant used to treat muscle spasm and the resulting pain or discomfort. It can also be administered for acute pain in general and for tension headache (muscle contraction headache). It acts on the spinal cord by depressing reflexes. It is sold under the brand names Lorzone, Paraflex and Muscol and in combination form as Parafon Forte, a combination of chlorzoxazone and acetaminophen (paracetamol). Possible side effects include dizziness, lightheadedness, malaise, nausea, vomiting.[ medical citation needed ] In rare cases, chlorzoxazone may cause severe liver dysfunction. [3] On the other hand, chlorzoxazone may reduce the liver toxicity of acetaminophen by competitive inhibition. [4]
It is available as a generic medication. [5]
Like metaxalone, its mechanism of action is still in question. It is believed that metaxalone works by altering serotonin levels and acting as a mild MAO inhibitor.[ medical citation needed ] The mechanism of action of chlorzoxazone is thought[ by whom? ] to act on GABAA and GABAB receptors and voltage-gated calcium channels to a degree.[ medical citation needed ] General central nervous system depression is the only currently accepted aspect to its medical benefits.[ medical citation needed ] Elucidation of the exact mechanism of action is ongoing but there is limited study due to the existence of more effective, safe muscle relaxants (e.g., diazepam, cyclobenzaprine, tizanidine), greatly limiting the potential benefit of identifying novel compounds which share chlorzoxazone's mechanism of action.
Hydrocodone, also known as dihydrocodeinone, is a semi-synthetic opioid used to treat pain and as a cough suppressant. It is taken by mouth. Typically, it is dispensed as the combination acetaminophen/hydrocodone or ibuprofen/hydrocodone for pain severe enough to require an opioid and in combination with homatropine methylbromide to relieve cough. It is also available by itself in a long-acting form sold under the brand name Zohydro ER, among others, to treat severe pain of a prolonged duration. Hydrocodone is a controlled drug: in the United States, it is classified as a Schedule II Controlled Substance.
Theophylline, also known as 1,3-dimethylxanthine, is a drug that inhibits phosphodiesterase and blocks adenosine receptors. It is used to treat chronic obstructive pulmonary disease (COPD) and asthma. Its pharmacology is similar to other methylxanthine drugs. Trace amounts of theophylline are naturally present in tea, coffee, chocolate, yerba maté, guarana, and kola nut.
Paracetamol, or acetaminophen, is a non-opioid analgesic and antipyretic agent used to treat fever and mild to moderate pain. It is a widely used over-the-counter medication. Common brand names include Tylenol and Panadol.
Disulfiram is a medication used to support the treatment of chronic alcoholism by producing an acute sensitivity to ethanol. Disulfiram works by inhibiting the enzyme aldehyde dehydrogenase, causing many of the effects of a hangover to be felt immediately following alcohol consumption. Disulfiram plus alcohol, even small amounts, produces flushing, throbbing in the head and neck, a throbbing headache, respiratory difficulty, nausea, copious vomiting, sweating, thirst, chest pain, palpitation, dyspnea, hyperventilation, fast heart rate, low blood pressure, fainting, marked uneasiness, weakness, vertigo, blurred vision, and confusion. In severe reactions there may be respiratory depression, cardiovascular collapse, abnormal heart rhythms, heart attack, acute congestive heart failure, unconsciousness, convulsions, and death.
A muscle relaxant is a drug that affects skeletal muscle function and decreases the muscle tone. It may be used to alleviate symptoms such as muscle spasms, pain, and hyperreflexia. The term "muscle relaxant" is used to refer to two major therapeutic groups: neuromuscular blockers and spasmolytics. Neuromuscular blockers act by interfering with transmission at the neuromuscular end plate and have no central nervous system (CNS) activity. They are often used during surgical procedures and in intensive care and emergency medicine to cause temporary paralysis. Spasmolytics, also known as "centrally acting" muscle relaxant, are used to alleviate musculoskeletal pain and spasms and to reduce spasticity in a variety of neurological conditions. While both neuromuscular blockers and spasmolytics are often grouped together as muscle relaxant, the term is commonly used to refer to spasmolytics only.
Hepatotoxicity implies chemical-driven liver damage. Drug-induced liver injury (DILI) is a cause of acute and chronic liver disease caused specifically by medications and the most common reason for a drug to be withdrawn from the market after approval.
Naproxen, sold under the brand name Aleve among others, is a nonsteroidal anti-inflammatory drug (NSAID) used to treat pain, menstrual cramps, and inflammatory diseases such as rheumatoid arthritis, gout and fever. It is taken orally. It is available in immediate and delayed release formulations. Onset of effects is within an hour and lasts for up to twelve hours. Naproxen is also available in salt form, naproxen sodium, which has better solubility when taken orally.
Cyclobenzaprine, sold under several brand names including, historically, Flexeril, is a muscle relaxer used for muscle spasms from musculoskeletal conditions of sudden onset. It is not useful in cerebral palsy. It is taken by mouth.
Cimetidine, sold under the brand name Tagamet among others, is a histamine H2 receptor antagonist that inhibits stomach acid production. It is mainly used in the treatment of heartburn and peptic ulcers.
Cytochrome P450 2E1 is a member of the cytochrome P450 mixed-function oxidase system, which is involved in the metabolism of xenobiotics in the body. This class of enzymes is divided up into a number of subcategories, including CYP1, CYP2, and CYP3, which as a group are largely responsible for the breakdown of foreign compounds in mammals.
Methocarbamol, sold under the brand name Robaxin among others, is a medication used for short-term musculoskeletal pain. It may be used together with rest, physical therapy, and pain medication. It is less preferred in low back pain. It has limited use for rheumatoid arthritis and cerebral palsy. Effects generally begin within half an hour. It is taken by mouth or injection into a vein.
Butalbital is a barbiturate with an intermediate duration of action. Butalbital is often combined with other medications, such as paracetamol (acetaminophen) or aspirin, for the treatment of pain and headache. The various formulations combined with codeine are FDA-approved for the treatment of tension headaches. Butalbital has the same chemical formula as talbutal but a different structure—one that presents as 5-allyl-5-isobutylbarbituric acid.
Hydralazine, sold under the brand name Apresoline among others, is a medication used to treat high blood pressure and heart failure. This includes high blood pressure in pregnancy and very high blood pressure resulting in symptoms. It has been found to be particularly useful in heart failure, together with isosorbide dinitrate, for treatment of people of African descent. It is given by mouth or by injection into a vein. Effects usually begin around 15 minutes and last up to six hours.
Metaxalone, sold under the brand name Skelaxin, is a muscle relaxant medication used to relax muscles and relieve pain caused by strains, sprains, and other musculoskeletal conditions. Its exact mechanism of action is not known, but it may be due to general central nervous system depression. It is a moderately strong muscle relaxant, with relatively low incidence of side effects.
Some fruit juices and fruits can interact with numerous drugs, in many cases causing adverse effects. The effect is most studied with grapefruit and grapefruit juice, but similar effects have been observed with certain other citrus fruits.
NAPQI, also known as NAPBQI or N-acetyl-p-benzoquinone imine, is a toxic byproduct produced during the xenobiotic metabolism of the analgesic paracetamol (acetaminophen). It is normally produced only in small amounts, and then almost immediately detoxified in the liver.
Hydrocodone/paracetamol is the combination of the pain medications hydrocodone and paracetamol (acetaminophen). It is used to treat moderate to severe pain. It is taken by mouth. Recreational use is common in the United States.
Thiocolchicoside is a muscle relaxant with anti-inflammatory and analgesic effects. Its mechanism of action is unknown, but it is believed to be act via antagonism of nicotinic acetylcholine receptors (nAchRs). However, it also appears to be a competitive antagonist of GABAA and glycine receptors. As such, it has powerful convulsant activity and should not be used in seizure-prone individuals.
Paracetamol poisoning, also known as acetaminophen poisoning, is caused by excessive use of the medication paracetamol (acetaminophen). Most people have few or non-specific symptoms in the first 24 hours following overdose. These symptoms include feeling tired, abdominal pain, or nausea. This is typically followed by absence of symptoms for a couple of days, after which yellowish skin, blood clotting problems, and confusion occurs as a result of liver failure. Additional complications may include kidney failure, pancreatitis, low blood sugar, and lactic acidosis. If death does not occur, people tend to recover fully over a couple of weeks. Without treatment, death from toxicity occurs 4 to 18 days later.
An analgesic adjuvant is a medication that is typically used for indications other than pain control but provides control of pain (analgesia) in some painful diseases. This is often part of multimodal analgesia, where one of the intentions is to minimize the need for opioids.