LINEZOLID IN SODIUM CHLORIDE 0.9% IN PLASTIC CONTAINER
Clinical safety rating
safeNo significant drug interactions Can cause hypernatremia and fluid overload.
Linezolid is an oxazolidinone antibiotic that inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, preventing formation of the 70S initiation complex.
| Metabolism | Linezolid is primarily metabolized by oxidation of the morpholine ring to form two inactive metabolites: aminoethoxyacetic acid and hydroxyethyl glycine. The exact enzyme system is not fully characterized, but it is believed to be non-enzymatic or via minor cytochrome P450 pathways. |
| Excretion | Renal excretion accounts for approximately 30% of the dose as unchanged drug; nonrenal clearance (likely hepatic metabolism) accounts for about 70%. Fecal excretion is minimal (<2%). |
| Half-life | Terminal elimination half-life is approximately 5.5 hours; in patients with severe renal impairment (CrCl <30 mL/min), half-life may be prolonged to 7-8 hours. |
| Protein binding | Approximately 31% bound to plasma proteins, primarily albumin (about 29%) and alpha-1-acid glycoprotein (about 10%). |
| Volume of Distribution | Steady-state volume of distribution is approximately 0.7 L/kg, indicating extensive distribution into well-perfused tissues (e.g., lungs, skin, muscle, and bone). |
| Bioavailability | Oral bioavailability is approximately 100%, with a 600 mg oral tablet yielding AUC equivalent to a 30-minute IV infusion of 600 mg. |
| Onset of Action | IV infusion: Onset of antibacterial effect is rapid, with peak plasma concentrations achieved at the end of a 30-120 minute infusion. Clinical response typically observed within 24-48 hours. |
| Duration of Action | Duration of action is approximately 12 hours, supporting twice-daily dosing. Linezolid exhibits time-dependent killing with postantibiotic effect of 1-2 hours against gram-positive bacteria. |
| Molecular Weight | 337.35 |
600 mg IV every 12 hours for 10-14 days.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for any degree of renal impairment. However, the two primary metabolites may accumulate in severe renal impairment, but clinical significance is unknown. |
| Liver impairment | No dose adjustment required for mild-to-moderate hepatic impairment (Child-Pugh A or B). Insufficient data for severe hepatic impairment (Child-Pugh C); use with caution. |
| Pediatric use | Neonates and children <12 years: 10 mg/kg IV every 8 hours for 10-14 days. Children ≥12 years: same as adult dosing. |
| Geriatric use | No specific dose adjustment based on age alone. Monitor renal function as clearance may decrease with age, but no dose change recommended. |
| 1st trimester | Linezolid has not been adequately studied in pregnant women during the first trimester. Animal studies have shown fetal toxicity at doses similar to human exposure. Use only if potential benefit justifies potential risk to the fetus. |
| 2nd trimester | Limited human data; animal studies indicate risks. Consider alternative antibiotics with more safety data. Use only if clearly needed. |
| 3rd trimester | As with other trimesters, safety not established. Avoid use near term due to possibility of neonatal adverse effects (e.g., serotonin syndrome if combined with serotonergic drugs). |
Clinical note
No significant drug interactions Can cause hypernatremia and fluid overload.
| FDA category | Animal |
| Placental transfer | Linezolid crosses the placenta in animal studies; human data are lacking. Based on molecular weight and pharmacokinetics, placental transfer is expected. |
| Breastfeeding | Linezolid is excreted into human breast milk. The manufacturer recommends caution; discontinue nursing or the drug, considering importance of drug to mother. Monitor infant for diarrhea, rash, and potential serotonin syndrome if mother is on serotonergic drugs. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Linezolid is classified as FDA Pregnancy Category C. Animal studies have shown embryotoxicity and fetal toxicity (reduced fetal weights, increased incidence of rib and vertebral anomalies) at doses approximately equivalent to the maximum human exposure. There are no adequate and well-controlled studies in pregnant women. In the first trimester, use only if potential benefit justifies potential risk to the fetus. In the second and third trimesters, limited data suggest no increased risk of major malformations, but potential for fetal effects due to maternal toxicity exists. |
| Fetal Monitoring | Monitor complete blood count (CBC) weekly due to risk of myelosuppression (thrombocytopenia, anemia, leukopenia). Monitor for signs of infection, bleeding, or bruising. Assess fetal growth and well-being with serial ultrasounds if used for prolonged periods. Monitor maternal blood pressure and heart rate. In neonates, monitor for lactic acidosis and peripheral neuropathy if maternal exposure near delivery. |
| Fertility Effects | No specific human studies on fertility. Animal studies: reversible reduced spermatogenesis and testicular degeneration in rats at doses equivalent to human exposure. Effect on female fertility unknown. Based on mechanism, no direct impact on ovulation or implantation anticipated, but may affect sperm quality. |
■ FDA Black Box Warning
Linezolid is not approved for the treatment of catheter-related bloodstream infections or catheter-site infections. An increased risk of mortality was seen in patients with catheter-related bloodstream infections in a clinical trial.
| Common Effects | fluid replacement |
| Serious Effects |
Known hypersensitivity to linezolid or any componentConcurrent use of serotonergic drugs (e.g., SSRIs, SNRIs, MAOIs, triptans, bupropion) unless patient can be monitored for serotonin syndromeUncontrolled hypertension, pheochromocytoma, carcinoid syndrome, thyrotoxicosis (due to MAO inhibition potential)Patients with untreated metabolic acidosis
| Precautions | Myelosuppression including anemia, leukopenia, thrombocytopenia, and pancytopenia, Peripheral and optic neuropathy, Lactic acidosis, Serotonin syndrome when coadministered with serotonergic agents, Convulsions, Clostridium difficile-associated diarrhea, Hypoglycemia in diabetic patients, Development of drug-resistant bacteria, Use in patients with uncontrolled hypertension, pheochromocytoma, carcinoid syndrome, or hyperthyroidism due to tyramine interactions |
| Food/Dietary | Avoid tyramine-containing foods and beverages to reduce risk of hypertensive crisis. Examples: aged cheeses (cheddar, blue cheese), cured/smoked meats (pepperoni, salami), fermented foods (sauerkraut, kimchi), soy products (tofu, miso), tap beers, red wines (Chianti), and overripe fruits (avocado, bananas). Patients should adhere to a low-tyramine diet during therapy and for 2 weeks after discontinuation. |
| Clinical Pearls | Linezolid is a reversible nonselective monoamine oxidase inhibitor (MAOI). Avoid concomitant use with serotonergic agents (e.g., SSRIs, SNRIs, triptans) due to risk of serotonin syndrome. Monitor for myelosuppression (especially thrombocytopenia) with prolonged therapy; complete blood counts should be checked weekly. Use with caution in uncontrolled hypertension, pheochromocytoma, or carcinoid syndrome due to potential for pressor response. Linezolid exhibits 100% oral bioavailability; intravenous form is used when oral route is not feasible. |
| Patient Advice | Avoid tyramine-rich foods and beverages (e.g., aged cheeses, cured meats, fermented products, tap beers, red wine) to prevent hypertensive crisis. · Report any signs of serotonin syndrome (e.g., agitation, hallucinations, rapid heart rate, fever, muscle twitching) or bleeding (easy bruising, petechiae). · Take exactly as prescribed; do not stop without consulting your doctor even if you feel better. · Inform all healthcare providers that you are taking linezolid, especially before surgery or receiving any new medications. |
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