Metronidazole 500 mg/100mL Injection, Solution
🆔 Identity & classification
Where does this data come from?
🏷️ RxNorm drug class
This medicine belongs to the Nitroimidazole Antimicrobial class.
Where does this data come from?
🏭 Manufacturer & labeler
Where does this data come from?
🩺 Clinical
Metronidazole injection is used to treat certain infections caused by bacteria. Metronidazole injection is also to prevent infection when used before, during, and after colorectal surgery. Metronidazole injection is in a class of medications called nitroimidazole antibacterials. It works by killing bacteria and protozoa that cause infection. Antibiotics such as metronidazole injection will not work for colds, flu, or other viral infections. Taking antibiotics when they are not needed increases your risk of getting an infection later that resists antibiotic treatment.
Read the full MedlinePlus article ↗- This is one of the most important things to know about metronidazole. If you drink alcohol — or consume products containing propylene glycol — while taking it, you can have a prett...
- Why do I have to avoid alcohol while taking this?
- Yes, completely normal and actually really important. Trichomoniasis is a sexually transmitted infection, so even if your partner has no symptoms, they can still carry the parasite...
- My partner and I both have to take this for trichomoniasis — is that normal?
Patient education
Supplement & herbal interactions
Some supplements/herbs that may interact with Metronidazole — tap one for details:
Metronidazole may be associated with lower levels of 7 nutrients — worth a chat with your pharmacist, not a cause for alarm.
Where does this data come from?
Ask a licensed pharmacist directly — free, answered by our team.
🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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22.9 mg / 100 mL
UNII XF417D3PSL
Anhydrous citric acid is a sour, crystalline powder derived from citric acid with water removed. In medicines, it acts as a buffer to control pH, adds tartness to improve taste, and helps tablets disintegrate.
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790 mg / 100 mL
UNII 451W47IQ8X
Sodium chloride is common table salt. It's used in medicines as a buffer to maintain proper pH, as a filler to add bulk, or to adjust the osmotic balance in liquid formulations.
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47.6 mg / 100 mL
UNII GR686LBA74
Sodium phosphate, dibasic is a salt derived from phosphoric acid. It acts as a buffer to help maintain the medicine's pH balance and may serve as a binder or filler in tablets and capsules.
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UNII 059QF0KO0R
Water is a liquid solvent that dissolves and mixes ingredients together in liquid medicines, syrups, and injections. It helps distribute the active drug evenly throughout the product.
4 inactive ingredients listed in the exact product block matched to this NDC.
Where does this data come from?
ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per mL | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | Not in the retail survey — common for institutional, discontinued, or low-volume packs. | |
| Medicaid paysCMS SDUD · 12 mo | $0.3609 | $866.16 / 2400 ml |
| Medicare drug plans payPart D · Q2 2026 | $0.0255 | $61.20 / 2400 ml |
| Medicare Part B allowsASP · J1836 | $0.033 / J1836 unit | — |
Where does this data come from?
🧾 Billing & reimbursement
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🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Metronidazole 500 mg/100mL 00264-5535-32 | B. | 100 ml | — | — | FDA listed | — |
| Metronidazole 500 mg/100mLthis 00338-1055-48 | Baxter | 100 ml | — | AP | FDA listed | — |
| Metronidazole 500 mg/100mL 00338-9541-24 | Baxter | 100 ml | — | AP | FDA listed | — |
| Metronidazole 500 mg/100mL 00404-9991-00 | Henry | 100 ml | — | AP | FDA listed | — |
| Metronidazole 5 mg/mL 00409-0152-24 | Hospira, | 24 pouches | — | AP | FDA listed | — |
| Metronidazole 500 mg/100mL 25021-0131-82 | Sagent | 24 pouches | — | AP | FDA listed | — |
| Metronidazole 500 mg/100mL 44567-0750-24 | WG | 24 pouches | — | AP | FDA listed | — |
| Metronidazole 500 mg/100mL 47335-0993-01 | Sun | 1 pouch | — | AP | FDA listed | — |
| Metronidazole 500 mg/100mL 68083-0373-04 | Gland | 4 pouches | — | AP | FDA listed | — |
| Metronidazole 500 mg/100mL 72572-0540-24 | Civica, | 100 ml | — | AP | FDA listed | — |
| Metronidazole 500 mg/100mL 80830-2465-09 | Amneal | 24 pouches | — | AP | FDA listed | — |
Where does this data come from?
⏳ Availability & generic status
The FDA lists approved generic versions of this medicine, but that does not always mean a pharmacy can get one today. Patent rules, launch agreements, supply and pricing can affect when generics actually arrive.
Where does this data come from?
🗺️ Medicaid utilization & spend
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
🔬 Reported adverse events (FAERS)
Top reported reactions
Age at onset
Reporter sex
Serious outcomes
Where does this data come from?
📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 00338-1055-48 You're viewing this | 24 BAG in 1 CARTON (0338-1055-48) / 100 mL in 1 BAG | 1981-12-24 | Active |
🧭 About this NDC listing & data coverage
What data is (and isn’t) available for this NDC — tap to expand
| NDC identity (package / product / labeler codes) | ✓ Available |
| Labeler | ✓ Available |
| Product & package description | ✓ Available |
| Marketing category & status | ✓ Available |
| Active ingredient / dosage form / route | ✓ Available |
| FDA label (SPL via DailyMed) | ✓ Available |
| Package photos | ✓ Available |
| Inactive ingredients (structured) | ✓ Available |
| NADAC pharmacy acquisition price (CMS) | — Not published for this NDC CMS publishes NADAC only for NDCs reported in its retail-pharmacy survey. |
| Orange Book / therapeutic-equivalence data | ✓ Available |
| HCPCS J-code billing crosswalk | ✓ Available |
| Medicaid utilization (CMS SDUD) | ✓ Available |
Questions about this listing
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📄 Full prescribing information FDA SPL
🚨 Boxed Warning ▾
WARNING Metronidazole has been shown to be carcinogenic in mice and rats (see PRECAUTIONS ). Unnecessary use of the drug should be avoided. Its use should be reserved for the conditions described in the INDICATIONS AND USAGE section below.
🎯 Indications and Usage ▾
INDICATIONS AND USAGE Treatment of Anaerobic Bacterial Infections Metronidazole Injection is indicated in the treatment of serious infections caused by susceptible anaerobic bacteria. Indicated surgical procedures should be performed in conjunction with Metronidazole Injection therapy. In a mixed aerobic and anaerobic infection, antibacterial drugs appropriate for the treatment of the aerobic infection should be used in addition to Metronidazole Injection.
Metronidazole Injection is effective in Bacteroides fragilis infections resistant to clindamycin, chloramphenicol and penicillin. • Intra-Abdominal Infections, including peritonitis, intra-abdominal abscess and liver abscess, caused by Bacteroides species including the B. fragilis group ( B. fragilis , B. distasonis , B. ovatus , B. thetaiotaomicron , B. vulgatus ), Clostridium species, Eubacterium species, Peptococcus species and Peptostreptococcus species in adults and pediatric patients less than 4 months of age. • Skin and Skin Structure Infections caused by Bacteroides species including the B. fragilis group, Clostridium species, Peptococcus species, Peptostreptococcus species and Fusobacterium species in adults. • Gynecologic Infections , including endometritis, endomyometritis, tubo-ovarian abscess and postsurgical vaginal cuff infection, caused by Bacteroides species including the B. fragilis group, Clostridium species, Peptococcus species, Peptostreptococcus species and Fusobacterium species in adults. • Bacterial Septicemia caused by Bacteroides species including the B. fragilis group and Clostridium species in adults. • Bone and Joint Infections , as adjunctive therapy, caused by Bacteroides species including the B. fragilis group in adults. • Central Nervous System (CNS) Infections , including meningitis and brain abscess, caused by Bacteroides species including the B. fragilis group in adults. • Lower Respiratory Tract Infections , including pneumonia, empyema and lung abscess, caused by Bacteroides species including the B. fragilis group in adults. • Endocarditis caused by Bacteroides species including the B. fragilis group in adults.
Prophylaxis Indication The prophylactic administration of Metronidazole Injection preoperatively, intraoperatively and postoperatively may reduce the incidence of postoperative infection in adult patients undergoing elective colorectal surgery which is classified as contaminated or potentially contaminated. Prophylactic use of Metronidazole Injection should be discontinued within 12 hours after surgery. If there are signs of infection, specimens for cultures should be obtained for the identification of the causative organism(s) so that appropriate therapy may be given (see DOSAGE AND ADMINISTRATION ).
Usage To reduce the development of drug-resistant bacteria and maintain the effectiveness of Metronidazole Injection and other antibacterial drugs, Metronidazole Injection should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
⏱️ Dosage and Administration ▾
DOSAGE AND ADMINISTRATION Dosage, rate of administration, and duration of treatment are to be individualized and depend upon the indication for use, the patient’s age, weight, clinical condition and concomitant treatment, and on the patient’s clinical and laboratory response to the treatment. Recommended Dosage for the Treatment of Anaerobic Bacterial Infections The recommended dosage schedule for adults for the treatment of anaerobic infections is presented in the Table 1 : Table 1. Recommended Dosage Schedule for the Treatment of Anaerobic Bacterial Infections in Adults Loading Dose 15 mg/kg infused intravenously over one hour (approximately 1 gram for a 70-kg adult).
Maintenance Dosage 7.5 mg/kg infused intravenously over one hour every six hours (approximately 500 mg for a 70-kg adult). The first maintenance dose should be instituted six hours following the initiation of the loading dose. Parenteral therapy may be changed to oral metronidazole therapy when conditions warrant, based upon the severity of the disease and the response of the patient to treatment with Metronidazole Injection.
The usual adult oral dosage is 7.5 mg/kg every six hours (approximately 500 mg for a 70-kg adult). A maximum of 4 grams should not be exceeded during a 24-hour period. The usual duration of therapy is 7 to 10 days; however, infections of the bone and joint, lower respiratory tract and endocardium may require longer treatment.
Recommended Dosage for the Treatment of Intra-Abdominal Infections in Pediatric Patients Less than 4 Months of Age: The recommended dosage schedule for pediatric patients less than 4 months of age for the treatment of intra-abdominal infections is described in Table 2 below. These dosage schedules achieve drug exposures in pediatric patients similar to adults treated with Metronidazole Injection for this indication. Table 2.
Recommended Dosage Schedule for the Treatment of Intra-Abdominal Infections in Pediatric Patients Less than 4 months of Age Post-menstrual age (Completed weeks) Loading Dose (mg/kg) Maintenance Dose The first maintenance dose is given 24 hours after the start of the loading dose. (mg/kg) Dosing interval (hours) 23 to <34 15 7.5 12 34 to 40 15 7.5 8 >40 to 48 15 7.5 6 Recommended Dosage in Patients with Severe Hepatic Impairment For patients with severe hepatic impairment (Child-Pugh C), the metronidazole dose should be reduced by 50% (see CLINICAL PHARMACOLOGY and PRECAUTIONS ).
Recommended Dosage in Patients Undergoing Hemodialysis Hemodialysis removes significant amounts of metronidazole and its metabolites from systemic circulation. The clearance of metronidazole will depend on the type of dialysis membrane used, the duration of the dialysis session, and other factors. If the administration of metronidazole cannot be separated from a hemodialysis session, supplementation of metronidazole dosage following a hemodialysis session should be considered, depending on the patient’s clinical situation (see CLINICAL PHARMACOLOGY ).
Dosage Considerations in Geriatric Patients In elderly patients the pharmacokinetics of metronidazole may be altered and, therefore, monitoring of serum levels may be necessary to adjust the metronidazole dosage accordingly. Recommended Prophylaxis Dosage For surgical prophylactic use, to prevent postoperative infection in contaminated or potentially contaminated colorectal surgery, the recommended dosage schedule for adults is: a. 15 mg/kg infused over 30 to 60 minutes and completed approximately one hour before surgery; followed by b.
7.5mg/kg infused over 30 to 60 minutes at 6 and 12 hours after the initial dose. It is important that (1) administration of the initial preoperative dose be completed approximately one hour before surgery so that adequate drug levels are present in the serum and tissues at the time of initial incision, and (2) Metronidazole Injection be administered, if necessary, at 6-hour intervals to maintain effective drug levels. Prophylactic use of Metr…
⛔ Contraindications ▾
CONTRAINDICATIONS • Hypersensitivity Metronidazole Injection is contraindicated in patients with a prior history of hypersensitivity to metronidazole or other nitroimidazole derivatives. • Psychotic Reaction with Disulfiram Use of oral metronidazole is associated with psychotic reactions in alcoholic patients who were using disulfiram concurrently. Do not administer metronidazole to patients who have taken disulfiram within the last two weeks (see PRECAUTIONS-Drug Interactions ). • Interaction with Alcohol Use of oral metronidazole is associated with a disulfiram-like reaction to alcohol, including abdominal cramps, nausea, vomiting, headaches, and flushing.
Discontinue consumption of alcohol or products containing propylene glycol during and for at least three days after therapy with metronidazole (see PRECAUTIONS-Drug Interactions ). • Cockayne Syndrome Metronidazole Injection is contraindicated in patients with Cockayne syndrome. Severe irreversible hepatotoxicity/acute liver failure with fatal outcomes have been reported after initiation of metronidazole in patients with Cockayne syndrome (see ADVERSE REACTIONS ).
⚠️ Warnings ▾
WARNINGS Severe Cutaneous Adverse Reactions Severe cutaneous adverse reactions (SCARs) including toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP) have been reported with the use of metronidazole. Symptoms can be serious and potentially life threatening. If symptoms or signs of SCARs develop, discontinue Metronidazole injection immediately and institute appropriate therapy.
Central and Peripheral Nervous System Effects Severe neurological disturbances, including encephalopathy, cerebellar symptoms, convulsive seizures, peripheral neuropathy, optic neuropathy, and aseptic meningitis, have been reported in patients treated with metronidazole. Encephalopathy associated with metronidazole may manifest as confusion or decreased level of consciousness, and is associated with widespread lesions on magnetic resonance imaging (MRI) of the brain. Cerebellar toxicity associated with metronidazole may manifest as ataxia, dizziness, dysarthria, nystagmus and saccadic pursuit and is accompanied by T2 flair lesions within the dentate nuclei seen on MRI.
Cerebellar toxicity may concurrently occur with encephalopathy, peripheral neuropathy or seizures. CNS symptoms and CNS lesions are generally reversible within days to weeks upon discontinuation of Metronidazole Injection. Peripheral neuropathy, usually symmetric and mainly of sensory type is characterized by numbness or paresthesia of an extremity.
Symptoms may be prolonged after drug discontinuation. Aseptic meningitis may occur within hours of dose administration and generally resolve after metronidazole therapy is discontinued (see ADVERSE REACTIONS ). Advise patients to report neurologic symptoms that occur during metronidazole administration.
Discontinue metronidazole treatment if any abnormal neurologic symptoms occur such as ataxia, dizziness, confusion or any other CNS adverse reaction (see ADVERSE REACTIONS ).
🤒 Adverse Reactions ▾
ADVERSE REACTIONS The following reactions have been reported during treatment with metronidazole formulations: INFECTIONS AND INFESTATIONS: Vaginal candidiasis BLOOD AND LYMPHATIC SYSTEM DISORDERS: Agranulocytosis, Leukopenia, Neutropenia, Thrombocytopenia, Eosinophilia IMMUNE SYSTEM DISORDERS: Anaphylactic reaction, Hypersensitivity METABOLISM AND NUTRITION DISORDERS: Decreased appetite PSYCHIATRIC DISORDERS: Confusional state, Depression, Insomnia, Decreased libido NERVOUS SYSTEM DISORDERS: Encephalopathy, Seizure, Neuropathy peripheral, Ataxia, Dizziness, Hypoesthesia, Paresthesia, Dysgeusia, Headache, Nystagmus, Aseptic meningitis, Somnolence, Dysarthria, Numbness, Syncope EYE DISORDERS: Optic neuropathy, Saccadic eye movement EAR AND LABYRINTH DISORDERS: Vertigo, tinnitus, hearing impairment, hearing loss CARDIAC DISORDERS: QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval.
Flattening of the T-wave may be seen in electrocardiographic tracings, Tachycardia, Palpitation RESPIRATORY, THORACIC AND MEDIASTINAL DISORDERS: Dyspnea GASTROINTESTINAL DISORDERS: Pancreatitis, Abdominal pain, Diarrhea, Nausea, Vomiting, Asthenia, Proctitis HEPATOBILIARY DISORDERS: Hepatotoxicity/Liver Failure in patients with Cockayne syndrome (see CONTRAINDICATIONS ), Jaundice SKIN AND SUBCUTANEOUS DISORDERS: Toxic epidermal necrolysis, Swelling face, Pruritus, Urticaria, Hyperhidrosis, Erythema, Rash; Stevens-Johnson syndrome, Fixed drug eruption, Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), acute generalized exanthematous pustulosis (AGEP) (see WARNINGS ) MUSCULOSKELETAL AND CONNECTIVE TISSUE DISORDERS: Muscle spasms, Arthralgia, Myalgia RENAL AND URINARY DISORDERS: Chromaturia, Dysuria Hepatic: Cases of severe irreversible hepatotoxicity/acute liver failure, including cases with fatal outcomes with very rapid onset after initiation of systemic use of metronidazole, have been reported in patients with Cockayne Syndrome (latency from drug start to signs of liver failure as short as 2 days) (see CONTRAINDICATIONS ) REPRODUCTIVE: Dyspareunia GENERAL DISORDERS AND ADMINISTRATION SITE CONDITIONS: Injection site reaction, Malaise, Face edema, Edema peripheral, Chest pain, Chills, INVESTIGATIONS: Hepatic enzyme increased.
Patients with Crohn's disease are known to have an increased incidence of gastrointestinal and certain extraintestinal cancers. There have been some reports in the medical literature of breast and colon cancer in Crohn's disease patients who have been treated with metronidazole at high doses for extended periods of time. A cause and effect relationship has not been established.
Crohn's disease is not an approved indication for Metronidazole Injection.
🔄 Drug Interactions ▾
Drug Interactions • Disulfiram Psychotic reactions and confusion have been reported in alcoholic patients who are using metronidazole and disulfiram concurrently. Do not administer Metronidazole Injection to patients who have taken disulfiram within the last two weeks (see CONTRAINDICATIONS ). • Alcoholic Beverages Abdominal cramps, nausea, vomiting, headaches, tachycardia and flushing may occur if alcoholic beverages or products containing propylene glycol are consumed during or following metronidazole therapy. Discontinue consumption of alcohol or products containing propylene glycol before, during and up to 72 hours after therapy with Metronidazole Injection (see CONTRAINDICATIONS ). • Warfarin and other Oral Anticoagulants Metronidazole has been reported to potentiate the anticoagulant effect of warfarin and other oral coumarin anticoagulants, resulting in a prolongation of prothrombin time and increased risk of hemorrhages.
When Metronidazole Injection is prescribed for patients on this type of anticoagulant therapy, prothrombin time and international normalized ratio (INR) should be carefully monitored and their anticoagulant dose adjusted accordingly. Monitor patients for signs and symptoms of bleeding. • Lithium In patients stabilized on relatively high doses of lithium, short-term metronidazole therapy has been associated with elevation of serum lithium and, in a few cases, signs of lithium toxicity. Lithium toxicity may lead to renal damage.
Frequent monitoring of serum lithium and serum creatinine levels is necessary. • Busulfan Metronidazole has been reported to increase plasma concentrations of busulfan, which can result in an increased risk for serious busulfan toxicity such as sinusoidal obstruction syndrome, gastrointestinal mucositis, and hepatic veno-occlusive disease. Metronidazole Injection should not be administered concomitantly with busulfan unless the benefit outweighs the risk. If no therapeutic alternatives to metronidazole are available, and concomitant administration with busulfan is medically needed, frequent monitoring of busulfan plasma concentration should be performed and the busulfan dose should be adjusted accordingly. • Drugs that Inhibit CYP450 Enzymes The simultaneous administration of drugs that decrease microsomal liver enzyme activity, such as cimetidine, may decrease metabolism and reduce plasma clearance of metronidazole which may result in metronidazole toxicity. • Drugs that Induce CYP450 Enzymes The simultaneous administration of drugs that induce microsomal liver enzyme activity, such as phenytoin or phenobarbital, may accelerate the elimination of metronidazole and therefore decrease its efficacy. • Cytochrome P450 3A4 (CYP3A4) substrates Concomitant use of Metronidazole Injection and CYP3A4 substrates (e.g., amiodarone, tacrolimus, cyclosporine, carbamazepine, phenytoin, and quinidine) may increase respective CYP3A4-substrate plasma levels.
Monitoring of plasma concentrations of CYP3A4 substrates may be necessary. • 5-Fluorouracil Metronidazole Injection decreases the clearance of 5-fluorouracil and may therefore cause 5-fluorouracil toxicity. • Vecuronium Metronidazole Injection may potentiate the effects of vecuronium. • Drugs that Prolong the QT interval QT prolongation has been reported, particularly when metronidazole was administered with drugs with the potential for prolonging the QT interval. • Drug/Laboratory Test Interactions Metronidazole may interfere with certain types of determinations of serum chemistry values, such as aspartate aminotransferase (AST, SGOT), alanine aminotransferase (ALT, SGPT), lactate dehydrogenase (LDH), triglycerides and glucose hexokinase.
Metronidazole causes an increase in ultraviolet absorbance at 340 nm resulting in falsely decreased values.
🤰 Pregnancy ▾
Pregnancy Teratogenic Effects There are no adequate and well-controlled studies of Metronidazole Injection in pregnant women. There are published data from case-control studies, cohort studies, and 2 meta-analyses that include more than 5000 pregnant women who used metronidazole during pregnancy. Many studies included first trimester exposures.
One study showed an increased risk of cleft lip, with or without cleft palate, in infants exposed to metronidazole in utero ; however, these findings were not confirmed. In addition, more than ten randomized, placebo-controlled clinical trials enrolled more than 5000 pregnant women to assess the use of antibiotic treatment (including metronidazole) for bacterial vaginosis on the incidence of preterm delivery. Most studies did not show an increased risk for congenital anomalies or other adverse fetal outcomes following metronidazole exposure during pregnancy.
Three studies conducted to assess the risk of infant cancer following metronidazole exposure during pregnancy did not show an increased risk; however, the ability of these studies to detect such a signal was limited. Metronidazole crosses the placental barrier and its effects on the human fetal organogenesis are not known. Reproduction studies have been performed in rats, rabbits and mice at doses similar to the maximum recommended daily dose based on body surface area comparisons.
There was no evidence of harm to the fetus due to metronidazole. Healthcare provider should carefully consider the potential risks and benefits for each specific patient before prescribing Metronidazole Injection.
🧒 Pediatric Use ▾
Pediatric Use Pediatric Patients Less than 4 Months of Age The safety and effectiveness of Metronidazole Injection have been established for the treatment of intraabdominal infections in pediatric patients from birth to less than 4 months. Use of Metronidazole Injection in this age group is supported by evidence from data in adults with additional pharmacokinetic and safety data in pediatric patients from birth to less than 4 months of age. A partially randomized, open-label, phase 2/3 study of intravenous Metronidazole Injection in combination with other intravenous antibacterial drugs was conducted in 62 preterm infants (≤ 33 weeks gestational age at birth, and postnatal age <121 days) and 55 late pre-term and term infants (≥ 34 weeks gestational age at birth, and postnatal age <121 days), with complicated intra-abdominal infections.
The primary objective of this study was to evaluate the safety of metronidazole-containing regimens, which were administered for up to 10 days. The adverse reactions reported in patients receiving metronidazole-containing regimens were comparable to patients receiving other antibacterial regimens in the study and generally similar to adverse reactions described in adults. The safety and effectiveness of Metronidazole Injection in pediatric patients less than 4 months of age have not been established for (1) the treatment of anaerobic infections other than intra-abdominal infections or for (2) prophylaxis for postoperative infections (see INDICATIONS AND USAGE , CLINICAL PHARMACOLOGY , Pediatric Patients and DOSAGE AND ADMINISTRATION ).
Pediatric Patients 4 Months of Age and Older The safety and effectiveness of Metronidazole Injection in pediatric patients 4 months of age and older have not been established.
🧓 Geriatric Use ▾
Geriatric Use In general, dose selection for an elderly patient should be cautious, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. In geriatric patients, monitoring for metronidazole associated adverse events is recommended (see CLINICAL PHARMACOLOGY , PRECAUTIONS ). Decreased liver function in geriatric patients can result in increased concentrations of metronidazole that may necessitate adjustment of metronidazole dosage (see DOSAGE AND ADMINISTRATION ).
🆘 Overdosage ▾
OVERDOSAGE Signs and symptoms of an overdose may include: nausea, vomiting, and neurotoxic effects, including ataxia, confusion, disorientation, seizures, and peripheral neuropathy. Treatment of Overdosage Symptomatic treatment is recommended. There is no specific antidote for an overdose of metronidazole.
Discontinue metronidazole administration in the event of an overdose. Hemodialysis removes significant amounts of metronidazole and its metabolites from systemic circulation.
🧬 Clinical Pharmacology ▾
CLINICAL PHARMACOLOGY In patients treated with intravenous metronidazole, using a dosage regimen of 15 mg/kg loading dose followed 6 hours later by 7.5 mg/kg every 6 hours, the average peak steady-state plasma concentrations (C max ) and trough concentrations (C min ) were 25 mcg/mL and 18 mcg/mL, respectively. Plasma concentrations of metronidazole are proportional to the administered dose. An eight-hour intravenous infusion of 100 mg to 4,000 mg of metronidazole in normal subjects showed a linear relationship between dose and peak plasma concentration.
The average elimination half-life of metronidazole in healthy subjects is eight hours. Distribution Metronidazole is the major component appearing in the plasma, with lesser quantities of metabolites also being present. Less than 20% of the circulating metronidazole is bound to plasma proteins.
Metronidazole appears in cerebrospinal fluid, saliva and breast milk in concentrations similar to those found in plasma. Bactericidal concentrations of metronidazole have also been detected in pus from hepatic abscesses. Following a single intravenous dose of metronidazole 500 mg, 4 healthy subjects who underwent gastrointestinal endoscopy had peak gastric juice metronidazole concentrations of 5 to 6 mcg/mL at one hour post-dose.
In patients receiving intravenous metronidazole in whom gastric secretions are continuously removed by nasogastric aspiration, sufficient metronidazole may be removed in the aspirate to cause a reduction in serum levels. Metabolism The metabolites of metronidazole result primarily from side-chain oxidation [1-(ß-hydroxyethyl)-2-hydroxymethyl-5-nitroimidazole and 2-methyl-5-nitroimidazole-1-yl-acetic acid] and glucuronide conjugation. Both the parent compound and the hydroxyl metabolite possess in vitro antimicrobial activity.
Excretion The major route of elimination of metronidazole and its metabolites is via the urine (60-80% of the dose), with approximately 20% of the amount excreted appearing as unchanged metronidazole. Renal clearance of metronidazole is approximately 10 mL/min/1.73 m 2 . Fecal excretion accounts for 6-15% of the dose.
Renal Impairment Decreased renal function does not alter the single-dose pharmacokinetics of metronidazole. Subjects with end-stage renal disease (ESRD; CL CR = 8.1±9.1 mL/min) and who received a single intravenous infusion of metronidazole 500 mg had no significant change in metronidazole pharmacokinetics but had 2-fold higher Cmax of hydroxy-metronidazole and 5-fold higher Cmax of metronidazole acetate, compared to healthy subjects with normal renal function (CL CR = 126 ± 16 mL/min). Thus, on account of the potential accumulation of metronidazole metabolites in ESRD patients, monitoring for metronidazole associated adverse events is recommended (see PRECAUTIONS ).
Effect of Dialysis Following a single intravenous infusion or oral dose of metronidazole 500 mg, the clearance of metronidazole was investigated in ESRD subjects undergoing hemodialysis or continuous ambulatory peritoneal dialysis (CAPD). A hemodialysis session lasting for 4 to 8 hours removed 40% to 65% of the administered metronidazole dose, depending on the type of the dialyzer membrane used and the duration of the dialysis session. If the administration of metronidazole cannot be separated from the dialysis session, supplementation of metronidazole dose following hemodialysis should be considered (see DOSAGE AND ADMINISTRATION ).
A peritoneal dialysis session lasting for 7.5 hours removed approximately 10% of the administered metronidazole dose. No adjustment in metronidazole dose is needed in ESRD patients undergoing CAPD. Hepatic Impairment Following a single intravenous infusion of 500 mg metronidazole, the mean AUC 24 of metronidazole was higher by 114% in patients with severe (Child-Pugh C) hepatic impairment, and by 54% and 53% in patients with a mild (Child-Pugh A) and moderate (Child-Pugh B) hepatic impairment, respectively, compared to healthy contro…
🧬 Mechanism of Action ▾
Mechanism of Action Metronidazole, a nitroimidazole, exerts antibacterial effects in an anaerobic environment against most obligate anaerobes. Once metronidazole enters the organism by passive diffusion and is activated in the cytoplasm of susceptible anaerobic bacteria, it is reduced; this process includes intra-cellular electron transport proteins such as ferredoxin, transfer of an electron to the nitro group of the metronidazole, and formation of a short-lived nitroso free radical. Because of this alteration of the metronidazole molecule, a concentration gradient is created and maintained which promotes the drug’s intracellular transport.
The reduced form of metronidazole and free radicals can interact with DNA leading to inhibition of DNA synthesis and DNA degradation leading to death of bacteria. The precise mechanism of action of metronidazole is unclear.
📦 How Supplied / Storage and Handling ▾
HOW SUPPLIED Metronidazole Injection, USP is supplied in 100 mL single dose plastic containers, each containing an iso-osmotic, buffered solution of 500 mg metronidazole as follows: 2B3421 NDC 0338-1055-48 500 mg/100 mL Store at controlled room temperature (77°F or 25°C) and protect from light during storage. Do not remove unit from overwrap until ready for use. The overwrap is a moisture barrier.
The inner bag maintains the sterility of the product. After removing overwrap, check for minute leaks by squeezing inner bag firmly. If leaks are found, discard solution as sterility may be impaired.
📋 Description ▾
DESCRIPTION Metronidazole Injection, USP, is a parenteral formulation of the synthetic nitroimidazole antibacterial agent 2-methyl-5-nitro-1 H -imidazole-1-ethanol. Metronidazole Injection, USP, in 100 mL VIAFLEX Plus single dose plastic container, is a sterile, nonpyrogenic, iso-osmotic, buffered solution of 500 mg Metronidazole, USP, 790 mg Sodium Chloride, USP, 47.6 mg Dibasic Sodium Phosphate Dried, USP and 22.9 mg Citric Acid Anhydrous, USP. Metronidazole Injection, USP has an osmolarity of 310 mOsmol/L (calc) and a pH of 5.5 (4.5 to 7.0).
Each container contains 14 mEq of sodium. The plastic container is fabricated from a specially formulated polyvinyl chloride plastic. Water can permeate from inside the container into the overwrap in amounts insufficient to affect the solution significantly.
Solutions in contact with the plastic container can leach out certain of its chemical components in very small amounts within the expiration period, e.g. , di-2-ethylhexyl phthalate (DEHP), up to 5 parts per million. However, the safety of the plastic has been confirmed in tests in animals according to USP biological tests for plastic containers as well as by tissue culture toxicity studies. Metronidazole, USP Structural Formula
💬 Information for Patients ▾
Information for Patients • Interaction with Alcohol Discontinue consumption of alcoholic beverages or products containing propylene glycol while taking Metronidazole Injection and for at least three days afterward because abdominal cramps, nausea, vomiting, headaches, and flushing may occur (see CONTRAINDICATIONS , PRECAUTIONS-Drug Interactions ). • Treatment of Bacterial Infections Patients should be counseled that antibacterial drugs including Metronidazole Injection should only be used to treat bacterial infections.
They do not treat viral infections ( e.g., the common cold). When Metronidazole Injection is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by Metronidazole Injection or other antibacterial drugs in the future. • Severe Cutaneous Adverse Reactions Advise patients that Metronidazole Injection may increase the risk of serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN), Stevens-Johnson syndrome (SJS), and drug reaction with eosinophilia and systemic symptoms (DRESS).
Instruct the patient to be alert for skin rash, blisters, fever or other signs and symptoms of these hypersensitivity reactions. Advise patients to stop Metronidazole Injection immediately if they develop any type of rash and seek medical attention.