Linezolid is an antibiotic used to treat certain serious bacterial infections. It works by stopping the growth of bacteria.

Linezolid also belongs to a class of drugs known as MAO inhibitors. It can increase the levels of certain natural substances in the body (such as dopamine, norepinephrine, serotonin) which can increase the chance of certain side effects and food and drug interactions. See How to Use, Side Effects, and Drug Interactions sections for more details.

This medication is given by injection into a vein as directed by your doctor, usually every 12 hours. It should be injected slowly over 30 minutes to 2 hours. The dosage is based on your medical condition and response to treatment. Children's dosage is also based on age and weight, and they may be directed to use this medication every 8 hours.

If you are using this medication at home, learn all preparation and usage instructions from your health care professional. Before using, check this product for particles or discoloration. If either is present, do not use the liquid. Learn how to store and discard medical supplies safely.

To prevent a very serious high blood pressure reaction, it is very important that you follow a special diet recommended by your doctor or dietician to limit your intake of tyramine while you are using this medicine. Avoid foods and beverages that are high in tyramine, including aged cheeses, dried/aged meats and sausages (such as salami, liverwurst), preserved fish (such as pickled herring), products that contain large amounts of yeast (such as bouillon cubes, powdered soup/gravy, homemade or sourdough bread), fermented foods (such as sauerkraut, kim chee), most soybean products (such as soy sauce, tofu), broad/fava beans, red wine, sherry, tap beers, and vermouth. Consult your doctor or dietician for more details and a complete list of other foods that contain tyramine which you should limit or avoid.

For the best effect, use this antibiotic at evenly spaced times. To help you remember, use this medication at the same time(s) every day.

Continue to use this medication until the full prescribed treatment period is finished, even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.

Tell your doctor if your condition lasts or gets worse.

Diarrhea, headache, nausea, vomiting, or dizziness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• deep/fast breathing
• unusual drowsiness
• nausea/vomiting that doesn't stop
• numbness/tingling of the hands/feet
• unusual tiredness
• easy bruising/bleeding
• muscle pain/tenderness/weakness

Get medical help right away if you have any very serious side effects, including:

• muscle stiffness
• increased sweating
• vision changes (such as blurred vision, change in color vision, loss of vision)
• mental/mood changes (such as agitation, confusion)
• seizure

This medication may rarely cause a severe intestinal condition due to a bacteria called C. difficile. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop:

• diarrhea that doesn't stop
• abdominal or stomach pain/cramping
• blood/mucus in your stool

If you have these symptoms, do not use anti-diarrhea or opioid products because they may make symptoms worse.

Use of this medication for prolonged or repeated periods may result in oral thrush or a new yeast infection. Contact your doctor if you notice white patches in your mouth, a change in vaginal discharge, or other new symptoms.

This medication may increase serotonin and rarely cause a very serious condition called serotonin syndrome/toxicity. The risk increases if you are also using other drugs that increase serotonin, so tell your doctor or pharmacist of all the drugs you use. Get medical help right away if you develop some of the following symptoms:

• fast heartbeat
• hallucinations
• loss of coordination
• severe dizziness
• severe nausea/vomiting/diarrhea
• twitching muscles
• unexplained fever
• unusual agitation/restlessness

This drug may rarely cause an attack of extremely high blood pressure (hypertensive crisis), which may be fatal. Many drug and food interactions can increase this risk (see How to Use and Drug Interactions sections). Get medical help right away if any of these serious side effects occur:

• severe headache
• fast/slow/irregular/pounding heartbeat
• chest pain
• neck stiffness/soreness
• severe nausea/vomiting
• sweating/clammy skin (sometimes with fever)
• widened pupils
• vision changes (such as double/blurred vision)
• sudden sensitivity to light (photophobia)

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using linezolid, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• high blood pressure
• blood/bone marrow problems (such as low red/white blood cells and platelets)
• kidney problems
• liver problems
• certain tumor conditions (such as pheochromocytoma, carcinoid syndrome)
• overactive thyroid
• seizures

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

If you have diabetes, linezolid may lower your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor. Tell your doctor right away if you have symptoms of low blood sugar such as sudden sweating, shaking, fast heartbeat, hunger, blurred vision, dizziness, or tingling hands/feet. Your doctor may need to adjust your diabetes medication, exercise program, or diet.

Linezolid may cause live bacterial vaccines (such as typhoid vaccine) to not work well. Tell your health care professional that you are using linezolid before having any immunizations/vaccinations.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This medication passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breastfeeding.

See also How to Use section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include:

• diet pills/appetite suppressants (such as diethylpropion)
• drugs for attention deficit disorder (such as atomoxetine, methylphenidate)
• apraclonidine
• bupropion
• buspirone
• carbamazepine
• cyclobenzaprine
• deutetrabenazine
• a certain combination product (dextromethorphan/quinidine)
• maprotiline
• methyldopa
• metoclopramide
• certain opioid pain relievers (such as fentanyl, meperidine, methadone, tapentadol)
• certain drugs for Parkinson's disease (such as entacapone, levodopa, tolcapone)
• certain supplements (such as tryptophan, tyramine)
• tetrabenazine
• tricyclic antidepressants (such as amitriptyline, doxepin)
• valbenazine

The risk of serotonin syndrome/toxicity increases if you are also using other drugs that increase serotonin. Examples include street drugs such as MDMA/"ecstasy," St. John's wort, certain antidepressants (including mirtazapine, SSRIs such as fluoxetine/paroxetine, SNRIs such as duloxetine/venlafaxine), tramadol, certain "triptans" used to treat migraine headaches (such as rizatriptan, sumatriptan, zolmitriptan), among others. The risk of serotonin syndrome/toxicity may be more likely when you start or increase the dose of these drugs.

Some products can interact with linezolid if you use them together, or even if you use them weeks before or after using linezolid. Tell your doctor or pharmacist if you use anything in the list of products that may interact with this drug, or any of the products that increase serotonin, within 2 weeks before or after using linezolid. Also tell them if you have taken fluoxetine within 5 weeks before starting linezolid. Ask your doctor how much time to wait between starting or stopping any of these drugs and starting linezolid.

Taking other MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Do not take any other MAO inhibitors (isocarboxazid, metaxalone, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before and after treatment with this medication. Ask your doctor when to start or stop using this medication.

Before using linezolid, report the use of drugs that may increase the risk of extremely high blood pressure (hypertensive crisis) when combined with linezolid, including herbal products (such as ephedra/ma huang), allergy and cold products (including decongestants such as phenylephrine/pseudoephedrine), and stimulants (such as amphetamines, ephedrine, epinephrine). Linezolid should not be used with any of these medications. Talk to your doctor or pharmacist for more details.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669.

Lab and/or medical tests (such as complete blood count, blood sodium levels) may be done while you are taking this medication. Eye tests should also be done if you take linezolid for 3 months or more, or if you have vision changes. Keep all medical and lab appointments.

It is important to get each dose of this medication as scheduled. If you miss a dose, ask your doctor or pharmacist right away for a new dosing schedule. Do not double the dose to catch up.

Store at room temperature. Protect from light and freezing. Keep the infusion bags in the foil outer wrap until ready to use. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.