Zyvox Side Effects

Generic Name: linezolid

Note: This page contains side effects data for the generic drug linezolid. It is possible that some of the dosage forms included below may not apply to the brand name Zyvox.

It is possible that some side effects of Zyvox may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

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


Linezolid (the active ingredient contained in Zyvox) 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.

Nervous system

Common (1% to 10%): Headache, dizziness
Frequency not reported: Drowsiness, seizure, Bell's palsy
Postmarketing reports: Serotonin syndrome (with concomitant serotonergic agents), convulsions, peripheral neuropathy

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 6 months of linezolid therapy for actinomycosis. The time from the onset of linezolid 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 linezolid discontinuation.

At least 15 instances of serotonin syndrome have been reported in patients using linezolid 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 linezolid therapy to the first sign of serotonin syndrome averaged 4 days (range: 1 to 20 days) and from the first sign to stopping linezolid 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 linezolid 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 linezolid 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 linezolid.

A 49-year-old male with multiple comorbidities developed symptoms on day 21 of linezolid 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). Linezolid 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. Linezolid 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.


Common (1% to 10%): Diarrhea, nausea, vomiting, elevated lipase, elevated amylase, taste alteration, tongue discoloration, oral moniliasis, localized abdominal pain, generalized abdominal pain
Frequency not reported: Constipation, dyspepsia, lingua villosa nigra, pseudomembranous colitis, Clostridium difficile colitis
Postmarketing reports: Superficial tooth discoloration, tongue discoloration

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 Clostridium difficile colitis after a long-term course of linezolid therapy.


Common (1% to 10%): Decreased hemoglobin, decreased platelet count, decreased white blood cells, decreased neutrophils, thrombocytopenia/low platelet count (some requiring platelet transfusions)
Frequency not reported: Red cell hypoplasia, decreased hematocrit, myelotoxicity
Postmarketing reports: Myelosuppression (including anemia, leukopenia, pancytopenia, thrombocytopenia)

Thrombocytopenia (platelets less than 100,000/mm3) has been reported in 32% of patients (n=19) receiving linezolid 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% receiving linezolid 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 linezolid therapy was held. Once hematologic levels returned to baseline, coadministration of linezolid with vitamin B6 resulted in stable hemoglobin levels for the remainder of linezolid therapy.

Another study compared linezolid plus 50 mg vitamin B6 per day (n=31) with linezolid 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.


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


Common (1% to 10%): Elevated alkaline phosphatase, elevated lactate dehydrogenase
Frequency not reported: Hyperlactatemia, metabolic acidosis, hyponatremia, hypokalemia
Postmarketing reports: Lactic acidosis, hypoglycemia (including symptomatic episodes)

At least 7 instances of lactic acidosis have been reported following linezolid therapy. The time from the onset of linezolid treatment to the first sign of lactic acidosis ranged from 1 to 16 weeks. Linezolid was stopped within 4 days of identifying lactic acidosis. Two of the 7 patients died despite stopping linezolid. The lactate levels normalized in the 5 surviving patients after stopping linezolid, but one of the patients had sequelae of blindness and disorientation.


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


Common (1% to 10%): Rash
Frequency not reported: Pruritus, mild alopecia
Postmarketing reports: Bullous skin disorders (such as those described as Stevens-Johnson syndrome)


Common (1% to 10%): Vaginal moniliasis


Common (1% to 10%): Fungal infection
Frequency not reported: Fever, generalized edema


Partially irreversible bilateral optic neuritis has been reported after 41 weeks of linezolid (the active ingredient contained in Zyvox) therapy.

Several cases of peripheral and/or optic neuropathy have been reported. The time from the onset of linezolid 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 linezolid due to optic neuropathy averaged 11 months (range: 1 to 56 months) after therapy initiation. Linezolid was stopped in 12 cases after the development of optic neuropathy; improvement or complete recovery was observed in all cases.

Frequency not reported: Partially irreversible bilateral optic neuritis
Postmarketing reports: Optic neuropathy (sometimes progressing to loss of vision)


Postmarketing reports: Anaphylaxis, angioedema


Frequency not reported: Interstitial pneumonia


Frequency not reported: Increased and decreased blood pressure, supraventricular tachycardia


Frequency not reported: Insomnia, confusion


Frequency not reported: Elevated creatine phosphokinase

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