Metronidazole Tablets

What is Metronidazole?

Metronidazole is an antibiotic medication belonging to the nitroimidazole class of drugs. It is specifically designed to treat infections caused by anaerobic bacteria and certain parasites. The medication works by entering bacterial and parasitic cells and interfering with their genetic material, ultimately leading to cell death.

Mechanism of Action

Metronidazole acts as a prodrug that becomes activated inside anaerobic microorganisms. Once inside these cells, it is reduced to its active form which creates toxic compounds that damage bacterial DNA, preventing the bacteria from reproducing and surviving. Think of it like a specialized key that only fits certain bacterial locks - once inside, it disrupts the bacteria's internal machinery.

This targeted action makes metronidazole particularly effective against the types of bacteria that thrive in low-oxygen environments, such as those responsible for bacterial vaginosis, dental infections, and gastrointestinal infections.

What is Metronidazole Used For?

Metronidazole is prescribed for various bacterial and parasitic infections, with its primary use for Bacterial Vaginosis being one of the most common applications.

Approved Indications

• Bacterial Vaginosis (BV): Restores the natural balance of bacteria in the vagina by eliminating harmful anaerobic bacteria
• Infections of the blood, brain, lung, bones, and genital tract
• Pelvic, stomach, and intestinal infections
• Gum ulcers and other dental infections
• Infected leg ulcers and pressure sores
• Prevention of infections after surgery

Before Using Metronidazole

Before starting treatment with metronidazole, it's important to discuss your medical history with your doctor to ensure this medication is appropriate for you.

Medical History Assessment

Inform your doctor if you have or have ever had:

• Liver problems or liver disease
• Kidney disease or are undergoing kidney dialysis
• Diseases of the nervous system
• Cockayne syndrome (requires frequent liver function monitoring)
• Allergies to metronidazole, other nitroimidazoles (like tinidazole), or any other medications

Required Baseline Tests

Your doctor may recommend:

• Liver function tests, especially if you have pre-existing liver conditions
• Pregnancy test if you are of childbearing potential
• Tests to confirm bacterial infection when appropriate

Metronidazole Contraindications

Metronidazole should not be used in certain situations due to potential health risks.

Absolute Contraindications

• Known allergy or hypersensitivity to metronidazole
• Allergy to other nitroimidazole antibiotics (e.g., tinidazole)
• Allergy to any of the ingredients listed in Section 9

Signs of Allergic Reaction

Stop taking metronidazole and seek immediate medical attention if you experience:

• Skin rash or hives
• Swelling of lips, face, throat or tongue
• Difficulty swallowing or breathing

Risk Stratification

Special Population Considerations

Elderly Patients

Elderly patients may be more susceptible to side effects, particularly neurological effects. Dosage adjustment may be necessary based on kidney and liver function.

Renal Impairment

For patients with severe kidney impairment or those undergoing dialysis, dosage adjustments may be necessary. Metronidazole and its metabolites are removed by haemodialysis.

Hepatic Impairment

Patients with liver disease may experience slower metabolism of metronidazole, potentially leading to accumulation and increased risk of side effects. Lower doses and monitoring of liver function are recommended.

Pediatric Patients

Metronidazole can be used in children, with dosage based on weight. For babies under 8 weeks of age, special dosing considerations apply as their liver enzyme systems are not fully developed.

Metronidazole and Other Medicines

Metronidazole can interact with other medications, potentially affecting how they work or increasing the risk of side effects.

High-Risk Medication Combinations

• Warfarin and other anticoagulants: Metronidazole may enhance the blood-thinning effect, increasing bleeding risk. Your doctor may need to adjust your warfarin dosage.
• Lithium: Metronidazole may increase lithium levels in the blood, potentially leading to toxicity. Kidney function should be monitored.
• Antiepileptic drugs (phenytoin, phenobarbital): These may reduce metronidazole effectiveness, while metronidazole may increase phenytoin levels.
• 5-fluorouracil: Metronidazole may increase the toxicity of this cancer medication.
• Busulfan: Metronidazole may increase busulfan levels, increasing toxicity risk.
• Ciclosporin: Metronidazole may increase ciclosporin levels, requiring monitoring.
• Disulfiram: Should not be taken with metronidazole due to increased risk of psychotic reactions.

Timing Recommendations

Always inform your doctor about all medications you are taking, including prescription, over-the-counter, and herbal products. Your doctor can advise on appropriate timing between doses of interacting medications.

Pregnancy & Breastfeeding

Pregnancy

Metronidazole should not be taken during pregnancy unless considered absolutely necessary by your doctor. The potential risks and benefits must be carefully evaluated.

Breastfeeding

Small amounts of metronidazole pass into breast milk. It is generally better to avoid using metronidazole while breastfeeding. If treatment is essential, your doctor may recommend temporarily discontinuing breastfeeding during treatment and for 2-3 days after the last dose to allow the medication to clear from your system.

Contraception Requirements

No specific contraception requirements are associated with metronidazole use alone, but you should discuss your contraceptive needs with your doctor based on your individual circumstances.

Driving & Machine Operation

Metronidazole may cause side effects that can impair your ability to drive or operate machinery safely.

Potential Impairments

• Drowsiness or sleepiness
• Dizziness
• Confusion
• Hallucinations (seeing or hearing things that aren't there)
• Convulsions (fits)
• Temporary eyesight problems (blurred or double vision)

Warning Signs to Watch For

If you experience any of the above symptoms, do not drive, operate machinery, or engage in any potentially dangerous activities until you know how metronidazole affects you. These effects are more likely to occur with higher doses or prolonged treatment.

Metronidazole Ingredients

Active Ingredient

• Metronidazole

Excipients (Inactive Ingredients)

The specific inactive ingredients may vary by manufacturer but typically include:

• Povidone (binder)
• Starch (filler)
• Magnesium stearate (lubricant)
• Other tablet-forming agents

Allergen Warnings

If you have known allergies to any medications or excipients, check the patient information leaflet for the specific product you are prescribed or consult your pharmacist.

How to Use Metronidazole

Follow these steps for proper use of metronidazole tablets:

1. Wash your hands before handling the medication
2. Take the tablet during or just after a meal to reduce stomach upset
3. Swallow the tablet whole with a full glass of water
4. Do not crush, break, or chew the tablets
5. Take at evenly spaced intervals as directed by your doctor
6. Complete the full course of treatment, even if you start to feel better

Metronidazole Dosage Guidelines

Dosage depends on the condition being treated, its severity, and patient factors. Always follow your doctor's specific instructions.

For Bacterial Vaginosis in Adults

For Other Infections in Adults

Pediatric Dosage

For children, the dosage is based on body weight and is determined by the prescribing doctor.

Administration Instructions

Optimal Timing

Take metronidazole at the same times each day to maintain consistent drug levels in your body. If prescribed multiple times daily, space doses evenly (e.g., every 8 hours for three times daily dosing).

With Food

Take metronidazole during or just after meals to minimize potential gastrointestinal side effects such as nausea or stomach upset.

Hydration

Swallow tablets with a full glass of water to ensure they pass easily into your stomach.

Missed Dose Management

Time-Based Guidance

Important Notes

• Do not take a double dose to make up for a forgotten tablet
• If you frequently forget doses, consider setting an alarm or using a pill organizer
• If you're unsure what to do about a missed dose, contact your pharmacist for advice

Overdose Information

Symptoms of Overdose

If you take too much metronidazole, you may experience:

• Nausea and vomiting
• Loss of coordination
• Numbness or tingling in arms and legs
• Convulsions (fits)

Management Protocol

If you suspect an overdose:

1. Seek immediate medical attention
2. Contact your local poison control center
3. Go to the nearest emergency department
4. Take the medication packaging with you

There is no specific antidote for metronidazole overdose. Treatment is supportive and focuses on managing symptoms.

Metronidazole Side Effects

Like all medicines, metronidazole can cause side effects, although not everybody gets them.

Frequency-Based Categorization

Very Common (may affect more than 1 in 10 people)

• Nausea
• Metallic taste in mouth

Common (may affect up to 1 in 10 people)

• Vomiting
• Diarrhoea
• Abdominal discomfort or pain
• Loss of appetite
• Headache
• Darkening of urine

Uncommon (may affect up to 1 in 100 people)

• Dizziness
• Drowsiness
• Skin rash
• Itching
• Candida infections (thrush)

Rare (may affect up to 1 in 1,000 people)

• Numbness or tingling in arms and legs
• Convulsions (fits)
• Confusion
• Hallucinations
• Liver problems
• Visual disturbances

Serious Side Effects Requiring Immediate Action

Stop taking metronidazole and contact your doctor immediately if you experience:

• Severe skin reactions: Reddish target-like spots, circular patches with central blisters, mouth/throat/nose/genital ulcers, red and swollen eyes (possible Stevens-Johnson syndrome or toxic epidermal necrolysis)
• AGEP: Red, scaly widespread rash with bumps and blisters accompanied by fever
• Liver problems: Stomach pain, loss of appetite, nausea, vomiting, fever, malaise, fatigue, jaundice (yellowing of skin/eyes), dark urine, pale stools, itching
• Severe allergic reactions: Difficulty breathing, swelling of face/lips/tongue/throat

How to Store Metronidazole

Temperature Requirements

• Store below 25°C
• Keep in the original packaging to protect from light and moisture
• Do not freeze

Safety Protocols

• Keep out of sight and reach of children
• Do not use after the expiry date printed on the packaging
• Do not throw away medicines via wastewater or household waste

Disposal Protocol

Return any unused medication to your pharmacy for proper disposal. This helps protect the environment and prevents accidental ingestion by others.

Metronidazole Pack Information

Available Pack Sizes

• 21 tablets (200mg) - typical 7-day course for twice-daily dosing
• 14 tablets (400mg) - typical 7-day course for twice-daily dosing
• Other pack sizes may be available depending on the manufacturer and pharmacy

Pack Contents

Each pack contains:

• Metronidazole tablets in blister strips
• Patient Information Leaflet

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