Linezolid Side Effects

Medically reviewed by Drugs.com. Last updated on Mar 29, 2025.

Applies to linezolid: oral powder for suspension, oral tablet.

Other dosage forms:

• intravenous solution

Precautions

It is very important that your doctor check your or your child's progress while you are taking this medicine, to see if the medicine is working properly. Blood and urine tests may be needed to check for any unwanted effects.

If your or your child's symptoms do not improve within 28 days or if they become worse, check with your doctor.

You should not use this medicine if you or your child have used an MAO inhibitor (MAOI), including isocarboxazid, phenelzine, Eldepryl®, Marplan®, Nardil®, or Parnate® within the past 14 days. Also, do not use this medicine if you or your child are also using the following medicines: buspirone (Buspar®), dobutamine (Dobutrex®), dopamine (Intropin®), epinephrine (Adrenalin®), norepinephrine (Levophed®), cold medicines or decongestants (eg, phenylpropanolamine, pseudoephedrine, or Sudafed®), medicine to treat depression (eg, amitriptyline, bupropion, doxepin, fluoxetine, nortriptyline, paroxetine, Celexa®, Effexor®, Elavil®, Lexapro®, Paxil®, or Zoloft®), medicine to treat migraine headaches (eg, sumatriptan, zolmitriptan, Axert®, Imitrex®, or Zomig®), or narcotic pain medicines (eg, meperidine, Demerol®).

Linezolid can lower the number of white blood cells in your blood temporarily, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions your doctor may ask you to take, especially when your blood count is low, to reduce the risk of infection or bleeding:

• If you can, avoid people with infections. Check with your doctor immediately if you think you or your child are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
• Check with your doctor immediately if you notice any unusual bleeding or bruising, black, tarry stools, blood in the urine or stools, or pinpoint red spots on your skin.

This medicine may cause infertility to men. Talk with your doctor before using this medicine if you plan to have children.

This medicine may cause diarrhea, and in some cases it can be severe. It may occur 2 months or more after you Stop taking linezolid. Do not take any medicine to treat diarrhea without first checking with your doctor. If you have any questions or if mild diarrhea continues or gets worse, check with your doctor.

You may develop low blood sugar while you or your child are taking this medicine. You may feel weak, drowsy, confused, anxious, or very hungry. You may have trouble seeing or have a headache that won't go away. Ask your doctor what you should do if this happens. Some things that can lead to low blood sugar are exercising more than normal or waiting too long to eat.

This medicine may cause a serious reaction called lactic acidosis (build-up of acid in the blood). Call your doctor right away if you or your child feel very tired, weak, or nauseated, if you vomit or have trouble breathing, or if you feel lightheaded or fainting.

This medicine may cause serious condition called serotonin syndrome when taken with certain medicines, including medicines to treat depression (SSRIs) or narcotic pain medicines. Check with your doctor first before taking any other medicines. Contact your doctor right away if you or your child experience agitation, confusion, diarrhea, fever, overactive reflexes, poor coordination, restlessness, shivering, sweating, or trembling or shaking.

Check with your doctor right away if blurred vision, difficulty in reading, or any other change in vision occurs during treatment with this medicine. Your eyes may need to be checked by an ophthalmologist (eye doctor).

When taken with certain foods or drinks, linezolid can cause an increase in blood pressure. To avoid this, do not eat large amounts of foods or drink beverages that have a high tyramine content (most common in foods that are aged, fermented, pickled, or smoked to increase their flavor, including aged cheeses, air-dried, fermented, or smoked fish, meat, or poultry, sauerkraut, soy sauce, red wine, or tap beer). If a list of these foods and beverages is not given to you, ask your doctor to provide one.

Check with your doctor right away if you have agitation, coma, confusion, decreased urine output, depression, dizziness, headache, hostility, increased thirst, irritability, lethargy, muscle pain or cramps, muscle twitching, nausea or vomiting, rapid weight gain, seizures, stupor, swelling of the face, ankles, or hands, or unusual tiredness or weakness. These may be symptoms of hyponatremia (low sodium levels in the blood) or syndrome of inappropriate antidiuretic hormone (SIADH).

Do not take other medicines unless thy have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Serious side effects of linezolid

Along with its needed effects, linezolid 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 while taking linezolid:

Other side effects of linezolid

Some side effects of linezolid 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:

For healthcare professionals

Applies to linezolid: intravenous solution, oral powder for reconstitution, oral tablet.

General adverse events

This drug was discontinued due to side effects in up to 3.5% of patients. The most common side effects leading to discontinuation were diarrhea, headache, nausea, and vomiting.^[Ref]

Nervous system

• Common (1% to 10%): Headache, dizziness, taste alteration/perversion (metallic taste)
• Uncommon (0.1% to 1%): Convulsions, hypoesthesia, paresthesia, tinnitus
• Frequency not reported: Drowsiness, seizure, Bell's palsy, sensory loss
• Postmarketing reports: Serotonin syndrome (with concomitant serotonergic agents), peripheral neuropathy^[Ref]

Several cases of peripheral and/or optic neuropathy have been reported, mainly when the duration of therapy was longer than 28 days. For example, irreversible sensory loss and peripheral neuropathy were reported in a patient after using this drug for 6 months for actinomycosis. The time from the onset of therapy to the first sign of peripheral neuropathy averaged 4 months (range: 10 days to 6 months) in 10 patients with only peripheral neuropathy. In all patients with peripheral neuropathy (n=16), complete recovery was not observed after this drug was stopped.

At least 15 instances of serotonin syndrome have been reported in patients using this drug with citalopram, sertraline, venlafaxine, fluoxetine, or paroxetine; other concurrent drugs and/or comorbidities may have contributed to the development of serotonin syndrome. The time from the onset of therapy to the first sign of serotonin syndrome averaged 4 days (range: 1 to 20 days) and from the first sign to stopping this drug ranged from 1 to 16 days. Symptoms resolved within 1 to 9 days in 14 patients while 1 patient died suddenly. Three patients died. The first patient developed symptoms 3 weeks after concurrent use of this drug and citalopram. Severe lactic acidosis developed followed by myocardial infarction, and after 3 further episodes of cardiac arrest, the patient died. The second patient stopped sertraline on day 1 and developed symptoms on day 9 of linezolid therapy. The patient had cardiopulmonary arrest, then anoxic brain injury, hypertension, tachycardia, and diarrhea, and died in 2 weeks; a similar incident occurred 6 weeks earlier when this drug and sertraline were used. The third patient, who was using citalopram, developed symptoms on day 2 of linezolid therapy and died with cerebral hemorrhage 1 month after the start of serotonin syndrome despite stopping this drug.

A 49-year-old male with multiple comorbidities developed symptoms on day 21 of therapy and was diagnosed with Bell's palsy; symptoms included strange sensation in mouth (no pain, sores, blisters), excessive tearing of left eye, inability to drink properly, left facial frowning, and left-sided facial weakness (involving upper and lower facial muscles). This drug was discontinued and the Bell's palsy completely resolved by day 90. The patient restarted linezolid 5 months later and again showed symptoms on day 21 of therapy. This drug was discontinued and by day 35, the Bell's palsy had practically resolved. The patient had no remaining symptoms 4 months after his second episode.

Convulsions have also been reported during postmarketing experience.^[Ref]

Gastrointestinal

• Common (1% to 10%): Diarrhea, nausea, vomiting, elevated lipase, elevated amylase, tongue discoloration, oral candidiasis, localized abdominal pain, generalized abdominal pain, constipation, dyspepsia
• Uncommon (0.1% to 1%): Pancreatitis, gastritis, abdominal distention, dry mouth, glossitis, loose stools, stomatitis, tongue disorder
• Rare (0.01% to 0.1%): Antibiotic-associated colitis (including pseudomembranous colitis), superficial tooth discoloration
• Frequency not reported: Clostridium difficile-associated diarrhea, lingua villosa nigra, C difficile colitis^[Ref]

In cases with known outcome, tooth discoloration was removable with professional dental cleaning (manual descaling).

A 60-year-old man with spondylodiscitis developed a fatal case of C difficile colitis after a long-term course of this drug.

Superficial tooth discoloration and tongue discoloration have also been reported during postmarketing experience.^[Ref]

Hematologic

• Common (1% to 10%): Decreased hemoglobin, decreased platelet count, decreased WBC count, anemia, decreased neutrophils, thrombocytopenia/low platelet count (some requiring platelet transfusions), decreased leukocytes, increased neutrophils, increased eosinophils, decreased hematocrit, decreased RBC count, increased platelet count, increased WBC count
• Uncommon (0.1% to 1%): Leukopenia, neutropenia, eosinophilia, increased reticulocyte count
• Rare (0.01% to 0.1%): Pancytopenia
• Frequency not reported: Red cell hypoplasia, myelotoxicity, bleeding events
• Postmarketing reports: Myelosuppression (including anemia, leukopenia, pancytopenia, thrombocytopenia), sideroblastic anemia^[Ref]

Thrombocytopenia (platelets less than 100,000/mm3) has been reported in 32% of patients (n=19) using this drug for more than 10 days. In another study (n=295), thrombocytopenia (platelets less than 150 x 10[9]/L) occurred in 6.4% of patients and severe thrombocytopenia (platelets less than 50 x 10[9]/L) occurred in 0.3% using this drug for more than 5 days. It has been suggested that the mechanism of linezolid-associated thrombocytopenia was immune-mediated.

In a study of patients with linezolid-associated thrombocytopenia, the use of vitamin B6 helped reverse the incidence of thrombocytopenia. Vitamin B6 was most effective when used after this drug was held. Once hematologic levels returned to baseline, coadministration of this drug with vitamin B6 resulted in stable hemoglobin levels for the remainder of therapy.

Another study compared this drug plus 50 mg vitamin B6 per day (n=31) with this drug alone (n=62) administered to patients with cancer. This study concluded vitamin B6 was not beneficial in the prevention of leukopenia or thrombocytopenia, but found a possible trend towards the prevention of anemia.^[Ref]

Hepatic

• Common (1% to 10%): Elevated ALT, elevated AST, abnormal liver function tests
• Uncommon (0.1% to 1%): Elevated total bilirubin^[Ref]

Metabolic

• Common (1% to 10%): Elevated alkaline phosphatase, elevated LDH, elevated nonfasting glucose
• Uncommon (0.1% to 1%): Hyponatremia, decreased nonfasting glucose
• Frequency not reported: Hyperlactatemia, metabolic acidosis, hypokalemia
• Postmarketing reports: Lactic acidosis, hypoglycemia (including symptomatic episodes)^[Ref]

At least 7 instances of lactic acidosis have been reported after use of this drug. The time from the onset of therapy to the first sign of lactic acidosis ranged from 1 to 16 weeks. This drug was stopped within 4 days of identifying lactic acidosis. Two of the 7 patients died despite stopping therapy. The lactate levels normalized in the 5 surviving patients after stopping this drug, but 1 of the patients had sequelae of blindness and disorientation.^[Ref]

Renal

• Common (1% to 10%): Elevated BUN
• Uncommon (0.1% to 1%): Elevated creatinine, renal failure
• Frequency not reported: Exacerbation of renal failure, abnormal renal function, acute interstitial nephritis^[Ref]

Dermatologic

• Common (1% to 10%): Rash, pruritus
• Uncommon (0.1% to 1%): Urticaria, dermatitis, diaphoresis
• Postmarketing reports: Bullous skin disorders (including severe cutaneous adverse reactions [SCAR] such as Stevens-Johnson syndrome and toxic epidermal necrolysis), angioedema, alopecia^[Ref]

Genitourinary

• Common (1% to 10%): Vaginal candidiasis
• Uncommon (0.1% to 1%): Vaginitis, polyuria, vulvovaginal disorder^[Ref]

Other

• Common (1% to 10%): Fungal infection, candidiasis, fever, localized pain, decreased total protein, decreased albumin, decreased sodium, decreased calcium, increased/decreased potassium, increased/decreased bicarbonate
• Uncommon (0.1% to 1%): Chills, fatigue, increased thirst, increased sodium, increased calcium, increased/decreased chloride
• Frequency not reported: Generalized edema^[Ref]

Ocular

• Uncommon (0.1% to 1%): Blurred vision
• Rare (0.01% to 0.1%): Changes in visual field defect
• Frequency not reported: Partially irreversible bilateral optic neuritis
• Postmarketing reports: Optic neuropathy (sometimes progressing to loss of vision), optic neuritis, loss of vision, changes in visual acuity, changes in color vision^[Ref]

Partially irreversible bilateral optic neuritis has been reported after 41 weeks of therapy.

Several cases of peripheral and/or optic neuropathy have been reported. The time from the onset of therapy to the first sign of optic neuropathy averaged 10 months (range: 1 to 48 months) in 6 patients with only optic neuropathy. The time to discontinuation of this drug due to optic neuropathy averaged 11 months (range: 1 to 56 months) after therapy initiation. This drug was stopped in 12 cases after the development of optic neuropathy; improvement or complete recovery was observed in all cases.^[Ref]

Cardiovascular

• Common (1% to 10%): Hypertension
• Uncommon (0.1% to 1%): Arrhythmia (tachycardia), transient ischemic attacks, phlebitis, thrombophlebitis
• Frequency not reported: Increased and decreased blood pressure, supraventricular tachycardia^[Ref]

Psychiatric

• Common (1% to 10%): Insomnia
• Frequency not reported: Confusion

Musculoskeletal

• Common (1% to 10%): Elevated creatine phosphokinase

Local

• Uncommon (0.1% to 1%): Injection site pain

Hypersensitivity

• Postmarketing reports: Anaphylaxis

Respiratory

• Frequency not reported: Interstitial pneumonia^[Ref]

See also:

Further information

Linezolid side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

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