Metaxalone

Metaxalone, a muscle relaxant, is used with rest, physical therapy, and other measures to relax muscles and relieve pain and discomfort caused by strains, sprains, and other muscle injuries.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

Metaxalone comes as a tablet to take by mouth. It usually is taken three or four times a day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take metaxalone exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Before taking metaxalone,

• tell your doctor and pharmacist if you are allergic to metaxalone or any other drugs.
• tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially medications for seizures, allergies, colds, or coughs; pain medications; sedatives; tranquilizers; and vitamins.
• tell your doctor if you have or have ever had kidney disease, liver disease, seizures, or a blood disorder.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking metaxalone, call your doctor immediately.
• you should know that this drug may make you drowsy. Do not drive a car or operate machinery until you know how metaxalone affects you.
• remember that alcohol can add to the drowsiness caused by this drug.

In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.

Metaxalone has not been adequately studied in pregnant women.

NURSING MOTHERS: It is not known whether metaxalone is excreted in breast milk. Safety for use in the nursing mother has not been established.

It’s always important to tell your doctor and pharmacist about all of your treatments, including over-the-counter (OTC) medications; vitamins, nutritional shakes, protein powders, and other supplements; herbal treatments or other alternative medicines; and any illegal or recreational drugs.

You should never take the following drugs while taking metaxalone:

• Antihistamines that contain carbinoxamine (such as Arbinoxa and Palgic)
• Doxylamine-containing drugs, such as Unisom or combination medicines
• Sodium oxybate (Xyrem), used to treat daytime sleepiness and some kinds of muscle problems

You should talk to your doctor or pharmacist before taking any of the following medications, which are known to interact with metaxalone:

• Allergy medicines, such as the antihistamines diphenhydramine (Benadryl), cetirizine (Zyrtec), fexofenadine (Allegra), or others
• Anxiety medications, including alprazolam (Xanax), lorazepam, diazepam (Valium), and others
• Seizure, convulsion, or epilepsy medicines
• Any sleep medicines
• Other muscle relaxants, such as carisoprodol (Soma) or cyclobenzaprine (Flexeril)
• Pain relievers that act through your nervous system, such as hydrocodone-containing products (like Lortab or Vicodon), morphine (Avinza), codeine-containing drugs (such as Tylenol #3), or others
• Medications that treat anxiety, depression, or other psychological states

Metaxalone and Alcohol

You should not consume alcohol or use any medication that dulls the nervous system while taking metaxalone, because it can be dangerous and make the effects of metaxalone too strong.

The FDA has a special warning against drinking alcohol while taking metaxalone — alcohol can increase the effects of the medicine, and it has contributed to deaths in overdose cases.

Metaxalone and Grapefruit Juice

Metaxalone is broken down by the liver, but its exact process is unknown.

Therefore, is it not clear if grapefruit juice affects how metaxalone works. To be on the safe side, avoid or limit your intake of grapefruit juice while taking the medicine.

Metaxalone and Other Interactions

Ask your pharmacist about the ingredients of cough and cold medicines before using them while you are taking metaxalone.

Some cough and cold drugs contain antihistamines or cause drowsiness, and should be taken with caution (or not at all) while you are on metaxalone.

Mechanism of Action

General CNS depression; no direct effect on skeletal muscle; may disrupt the spasm-pain-spasm cycle; does not havae direct effect on skeletal muscle

Absorption

Onset: Within 1 hr

Duration: 4-6 hr

Peak plasma time: 3 hr

Peak plasma concentration: 296 mcg/mL

Distribution

Vd: 800 L

Metabolism

Liver

Metabolites: Unidentified

Elimination

Half-life elimination: 4-14 hr

Excretion: Urine

Metaxalone is a prescription medication used with rest, physical therapy, and other measures to relax muscles and relieve pain caused by muscle injuries.

This medication may be prescribed for other uses.  Ask your doctor or pharmacist for more information.

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The recommended dose of Skelaxin (metaxalone) for muscle spasms is 800 mg orally 3 to 4 times a day.

If you take too much metaxalone, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using metaxalone and call your doctor at once if you have:

• weak or shallow breathing;

• a light-headed feeling, like you might pass out;

• pale or yellowed skin, dark colored urine, fever, confusion or weakness; or

• upper stomach pain, loss of appetite, jaundice (yellowing of the skin or eyes).

Common side effects may include:

• dizziness, drowsiness;

• nausea, vomiting, upset stomach;

• headache; or

• feeling nervous or irritable;

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Taking metaxolone with other drugs that make you sleepy or slow your breathing can cause dangerous or life-threatening side effects. Ask your doctor before taking a sleeping pill, narcotic pain medicine, prescription cough medicine, a muscle relaxer, or medicine for anxiety, depression, or seizures.

Other drugs may interact with metaxalone, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Contraindications

• History of drug-induced, hemolytic, or other anemia.101 b

• Substantial hepatic or renal impairment.101 b

• Known hypersensitivity to metaxalone or any ingredient in the formulation.101 b

Warnings/Precautions

Warnings

May enhance the effects of other CNS depressants.101 b (See Specific Drugs and Laboratory Tests under Interactions.)

Sensitivity Reactions

Possible hypersensitivity reactions.101 b

Specific Populations

Category B.

Animal studies have failed to reveal fetal risk, but safe use during pregnancy has not been established; do not use in women who are or may become pregnant unless possible benefits outweigh potential risks.101 b

Not known whether metaxalone is distributed into milk.101 Use not recommended.101 b

Safety and efficacy not established in children ≤12 years of age.101 b

Use with caution due to greater frequency of decreased hepatic or renal function and of concomitant disease and drug therapy observed in the elderly.101 b

Use great caution in patients with a history of liver disease.101 b Perform liver function tests periodically during metaxalone therapy.101 b

Contraindicated in patients with substantial hepatic impairment.101 b

Caution advised; contraindicated in patients with substantial renal impairment.101 b

Common Adverse Effects

Drowsiness, dizziness, headache, nervousness or irritability, nausea, vomiting, GI upset.101 b

Storage

Oral

15–30°C.101 b

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For metaxalone, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to metaxalone or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of metaxalone in children 12 years of age and younger. Safety and efficacy have not been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of metaxalone in the elderly. However, elderly patients are more likely to have age-related kidney or liver problems, which may require caution in patients receiving metaxalone.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

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 metaxalone, 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 metaxalone 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
• Bromazepam
• Buprenorphine
• Butabarbital
• Butalbital
• Butorphanol
• Carisoprodol
• Chloral Hydrate
• Chlordiazepoxide
• Chlorzoxazone
• Clobazam
• Clonazepam
• Clorazepate
• Codeine
• Dantrolene
• Diazepam
• Dihydrocodeine
• Doxylamine
• Estazolam
• Ethchlorvynol
• Fentanyl
• Flibanserin
• Flunitrazepam
• Flurazepam
• Halazepam
• Hydrocodone
• Hydromorphone
• Ketazolam
• Levorphanol
• Lorazepam
• Lormetazepam
• Medazepam
• Meperidine
• Mephenesin
• Mephobarbital
• Meprobamate
• Metaxalone
• Methadone
• Methocarbamol
• Methohexital
• Midazolam
• Morphine
• Morphine Sulfate Liposome
• Nalbuphine
• Nitrazepam
• Oxazepam
• Oxycodone
• Oxymorphone
• Pentazocine
• Pentobarbital
• Periciazine
• Phenobarbital
• Prazepam
• Primidone
• Quazepam
• Remifentanil
• Secobarbital
• Sodium Oxybate
• Sufentanil
• Tapentadol
• Temazepam
• Thiopental
• Tramadol
• Triazolam
• Zolpidem

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of metaxalone. Make sure you tell your doctor if you have any other medical problems, especially:

• Anemia or
• Kidney disease, severe or
• Liver disease, severe—Should not be used in patients with these conditions.

• Kidney disease or
• Liver disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

Use this medicine as ordered by your doctor. Read all information given to you. Follow all instructions closely.

• Take with or without food. Taking metaxalone with food may cause more sleepiness or dizziness.

What do I do if I miss a dose?

• If you take this medicine on a regular basis, take a missed dose as soon as you think about it.
• If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
• Do not take 2 doses at the same time or extra doses.
• Many times metaxalone is taken on an as needed basis. Do not take more often than told by the doctor.

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Feeling very tired or weak.
• Fever or chills.
• Sore throat.
• Very bad belly pain.
• Dark urine or yellow skin or eyes.
• A very bad and sometimes deadly health problem called serotonin syndrome may happen. The risk may be greater if you take this medicine with drugs for depression, migraines, or certain other drugs. Call your doctor right away if you have agitation; change in balance; confusion; hallucinations; fever; fast or abnormal heartbeat; flushing; muscle twitching or stiffness; seizures; shivering or shaking; sweating a lot; very bad diarrhea, upset stomach, or throwing up; or very bad headache.

Known hypersensitivity to any components of this product.

Known tendency to drug induced, hemolytic, or other anemias.

Significantly impaired renal or hepatic function.

Metaxalone Tablets, USP 800 mg are available as pink, capsule shape scored tablet debossed with ‘SG’ on scored side and ‘323’ on the other.

NDC 55111-650-01: Bottles of 100 Tablets

Store at 20° to 25°C (68° to 77°F); excursions permitted to 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature]. Dispense in well-closed, light-resistant containers.

You can ask your pharmacist or doctor for information about Metaxalone Tablets USP, or call 1-888-375-3784.

Rx Only

Manufactured by:
ScieGen Pharmaceuticals, Inc.
Hauppauge, NY 11788, USA

Manufactured for:
Dr.Reddy’s Laboratories Inc.
Princeton, New Jersey 08540, USA


Issued: 06/17

Precise mechanism has not been established; however, its clinical effect may be associated with general depression of the nervous system; has no direct effect on the contractile mechanism of striated muscle, the nerve fiber or the motor end plate.

Distribution

Vd: ~800 L

Metabolism

Hepatic via CYP1A2, CYP2D6, CYP2E1, CYP3A4 and to lesser extent CYP2C8, CPY2C9, and CYP2C19

Excretion

Urine (as metabolites)

Time to Peak

~3 hours

Half-Life Elimination

9 ± 4.8 hours

An increase in bioavailability and half-life have been observed in female patients.

Musculoskeletal conditions: Relief of discomforts associated with acute, painful musculoskeletal conditions.

Hypersensitivity to metaxalone or any component of the formulation; significantly impaired hepatic or renal function, tendency to drug-induced, hemolytic, or other anemias

Musculoskeletal conditions: Adolescents ≥13 years: Refer to adult dosing.

False-positive Benedict's test