0.5% W/V METRONIDAZOLE INJECTION USP Infusion/Solution for

What is 0.5% W/V METRONIDAZOLE INJECTION USP

0.5% w/v Metronidazole Injection USP is a sterile, ready-to-use intravenous solution containing Metronidazole, an antiprotozoal and antibacterial agent. It is primarily used for the treatment and prophylaxis of anaerobic bacterial infections, particularly in surgical settings. This formulation is delivered in a 100ml plastic bag and is intended for infusion under professional supervision.

• Active Ingredient: Metronidazole 0.5% w/v (5 mg/ml)
• Pharmaceutical Form: Intravenous infusion solution
• Container: 100 ml plastic bag (single-use)
• Drug Class: Nitroimidazole antibiotic

This medication is commonly used for:

• Treatment of infections caused by anaerobic bacteria such as Bacteroides fragilis
• Gynecological and intra-abdominal infections
• Prophylaxis before colorectal and gynecological surgeries
• Treatment of Clostridium difficile-associated diarrhea (off-label in some countries)

Its spectrum is largely directed against obligate anaerobes and certain protozoal organisms. The intravenous form is particularly beneficial in patients who cannot take oral medication due to severe illness, vomiting, or gastrointestinal surgery.

How to use 0.5% W/V METRONIDAZOLE INJECTION USP

0.5% w/v Metronidazole Injection USP should be administered by a healthcare professional under aseptic conditions, typically in a hospital or clinical setting. It is intended for intravenous infusion only and should never be injected as a bolus or intramuscularly.

• Route of Administration: Intravenous (IV) infusion
• Infusion Time: Usually over 30 to 60 minutes, depending on dose and clinical condition
• Dilution: The solution is pre-diluted and ready for use; no further dilution is typically required

General guidelines for administration include:

• Inspect the bag for particulate matter or discoloration before use
• Use only if the solution is clear and the container is intact
• Connect to IV set using aseptic technique
• Discard any unused portion after administration (single-use only)

Monitoring is essential during infusion, especially for long-term use or in patients with liver dysfunction, as Metronidazole is primarily metabolized by the liver. Liver function tests and complete blood counts may be conducted during prolonged therapy.

Mode of Action 0.5% W/V METRONIDAZOLE INJECTION USP

Metronidazole exerts its antimicrobial effect through a unique mechanism that specifically targets anaerobic organisms. Its mode of action is based on disrupting the DNA synthesis of susceptible organisms, ultimately leading to cell death.

• Intracellular Activation: Metronidazole is a prodrug that requires activation inside anaerobic organisms
• Reduction Process: In anaerobic environments, it is reduced by ferredoxin-linked processes into reactive nitro radicals
• DNA Disruption: These reactive intermediates bind to DNA and inhibit nucleic acid synthesis
• Bactericidal Effect: Leads to cell death and resolution of infection

The drug is especially effective against:

• Bacteroides species
• Clostridium species
• Trichomonas vaginalis (protozoal infection)
• Entamoeba histolytica and Giardia lamblia (protozoa)

Metronidazole has excellent tissue penetration, including abscess cavities and body fluids, making it a preferred agent in anaerobic systemic infections. It is also used as part of combination regimens in complex infections such as pelvic inflammatory disease or post-surgical infections.

0.5% W/V METRONIDAZOLE INJECTION USP Interactions 0.5% W/V METRONIDAZOLE INJECTION USP

Metronidazole has several significant drug interactions that must be considered before initiating therapy. These interactions can potentiate toxicity or reduce the effectiveness of either drug.

• Alcohol: Concurrent use may cause a disulfiram-like reaction (nausea, vomiting, flushing, tachycardia)
• Warfarin and other anticoagulants: Metronidazole can potentiate the anticoagulant effect, increasing INR
• Disulfiram: Should not be used within 2 weeks of disulfiram therapy due to risk of psychotic reactions
• Phenytoin and phenobarbital: May accelerate metabolism of metronidazole, decreasing its efficacy
• Cyclosporine: Concomitant use may increase serum cyclosporine levels

Other interactions to monitor include:

• Lithium: Metronidazole may raise lithium plasma concentrations, increasing the risk of nephrotoxicity
• 5-Fluorouracil: Increased toxicity of 5-FU may occur
• Busulfan: Risk of elevated busulfan levels leading to toxicity

Patients should inform their physician of all current medications, including over-the-counter drugs and supplements, to avoid adverse interactions.

Dosage of 0.5% W/V METRONIDAZOLE INJECTION USP

Dosage of Metronidazole Injection varies depending on the type and severity of infection, age, weight, and renal or hepatic function. Below are general dosing guidelines:

• Adults: 500 mg (100 ml) every 8 hours by IV infusion over 30–60 minutes
• Severe infections: Dose may be increased up to 4 grams per day in divided doses
• Prophylaxis for surgery: 500 mg pre-operatively, followed by additional doses post-surgery if necessary

In pediatric patients:

• Neonates and children: Dosage is weight-based, typically 7.5 mg/kg every 8 hours

Special considerations:

• Renal Impairment: Dose adjustment usually not required unless on dialysis
• Hepatic Impairment: Use with caution; consider dose reduction
• Duration of therapy: Typically 7 to 10 days, depending on the infection

Always follow physician’s instructions or institutional protocols for dose titration and treatment duration.

Possible side effects of 0.5% W/V METRONIDAZOLE INJECTION USP

While generally well-tolerated, Metronidazole Injection may cause adverse effects, particularly with prolonged use or high doses. Most side effects are mild and reversible, but some may require medical attention.

• Common Side Effects:
  • Nausea, vomiting
  • Metallic taste in the mouth
  • Headache
  • Loss of appetite
  • Abdominal cramps
• Less Common but Serious Effects:
  • Seizures or peripheral neuropathy (especially in prolonged use)
  • Darkening of urine
  • Allergic reactions (rash, pruritus, angioedema)
  • Hepatotoxicity
  • Blood dyscrasias (e.g., leukopenia)

Patients should immediately report:

• Numbness or tingling in limbs
• Severe dizziness or unsteady gait
• Yellowing of the skin or eyes
• Signs of allergic reactions

Routine monitoring is advised during extended treatment to detect early signs of toxicity.

0.5% W/V METRONIDAZOLE INJECTION USP Contraindications 0.5% W/V METRONIDAZOLE INJECTION USP

The use of Metronidazole Injection is contraindicated in certain patients due to the risk of adverse reactions or exacerbation of existing conditions.

• Hypersensitivity: Known allergy to Metronidazole or other nitroimidazole derivatives
• First trimester of pregnancy: Use only if absolutely necessary, as it may cross the placenta
• Alcohol consumption: Avoid during and for at least 48 hours after treatment due to disulfiram-like reaction
• Neurological disorders: Use cautiously in patients with epilepsy or other CNS disorders
• Hepatic impairment: Dose adjustment and careful monitoring required

Relative contraindications include:

• History of blood dyscrasias
• Concurrent use with disulfiram or alcohol

Always review patient history thoroughly before initiating treatment.

Storage of 0.5% W/V METRONIDAZOLE INJECTION USP

p>Proper storage conditions are essential to maintain the efficacy and sterility of Metronidazole Injection. Here are the recommended guidelines:

• Temperature: Store between 15°C to 25°C (59°F to 77°F)
• Light Protection: Protect from direct sunlight and UV exposure
• Freezing: Do not freeze; freezing may compromise solution stability
• Container Integrity: Use only if the solution is clear and the bag is intact
• Shelf-life: Refer to the manufacturer’s label; do not use after expiration

After opening or partial use:

• Single-use only – discard any unused portion immediately after infusion
• Do not reconnect partially used containers to other infusion systems

Always follow local hospital or pharmacy protocols for the safe storage and disposal of parenteral medications.