Metronidazole 375mg Capsules

Metronidazole is a prodrug that is activated by susceptible anaerobic bacteria and protozoa. The nitro group of metronidazole is reduced by electron transport proteins in anaerobic organisms to highly reactive nitro radicals. These radicals damage DNA and other macromolecules, leading to cell death. It also inhibits nucleic acid synthesis.

Urgent Side Effects: Seek Medical Help Immediately

Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:

Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Redness or white patches in the mouth or throat
Vaginal itching or discharge
Fast or abnormal heartbeat
Pain when passing urine or blood in urine
Frequent urination
Pelvic pain
Ringing in the ears, hearing loss, or other changes in hearing

Nervous System Problems

This medication can cause nervous system problems, which may be long-lasting. If you experience any of the following symptoms, contact your doctor right away:

Burning, numbness, or tingling sensations that are not normal
Changes in balance or eyesight
Dizziness or fainting
Headache
Insomnia
Seizures
Speech difficulties
Confusion, depression, irritability, fatigue, or weakness

Aseptic Meningitis

This medication may increase the risk of a severe brain problem called aseptic meningitis. If you experience any of the following symptoms, contact your doctor right away:

Headache
Fever
Chills
Severe nausea or vomiting
Stiff neck
Rash
Sensitivity to light
Drowsiness
Confusion

Low White Blood Cell Count

This medication can cause a low white blood cell count, which may increase the risk of infection. If you experience any of the following symptoms, contact your doctor right away:

Fever
Chills
Sore throat

Severe Skin Reactions

This medication can cause severe skin reactions, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious reactions. If you experience any of the following symptoms, seek medical help immediately:

Red, swollen, blistered, or peeling skin
Red or irritated eyes
Sores in the mouth, throat, nose, eyes, genitals, or skin
Fever
Chills
Body aches
Shortness of breath
Swollen glands

Other Side Effects

Most people do not experience serious side effects, but some may occur. If you experience any of the following side effects, contact your doctor if they bother you or do not go away:

Constipation
Diarrhea
Stomach pain
Upset stomach
Vomiting
Decreased appetite
Stomach cramps
Metallic taste
Headache
Joint pain
* Decreased libido

Reporting Side Effects

If you have questions about side effects or want to report a side effect, contact your doctor or the FDA at 1-800-332-1088. You can also report side effects online at https://www.fda.gov/medwatch.

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have Cockayne syndrome, as some individuals with this condition have developed liver problems while taking this medication. In some cases, these liver issues have been severe, persistent, or even fatal.
If you have taken disulfiram within the past 14 days.
If you are less than 12 weeks pregnant, as this medication is not intended for use in certain patients during this stage of pregnancy.

This list is not exhaustive, and it is crucial to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health issues with your doctor and pharmacist. They will help determine whether it is safe to take this medication in combination with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Regular blood tests will be necessary, as directed by your doctor, to monitor your condition. Be sure to discuss any concerns or questions with your doctor.

As this medication may interfere with certain laboratory tests, it is crucial to notify all healthcare providers and laboratory personnel that you are taking this drug. If you are undergoing dialysis, consult with your doctor to discuss any potential interactions.

To minimize potential side effects, you may need to avoid consuming alcohol or products containing alcohol or propylene glycol during treatment with this medication and for at least 72 hours after your last dose. Examples of products that may contain alcohol or propylene glycol include some cough syrups. Consuming these substances may cause stomach cramps, nausea, vomiting, headaches, and flushing. Consult with your doctor to determine if avoidance of these substances is necessary for your specific situation.

Do not exceed the recommended treatment duration, as this may increase the risk of a secondary infection. If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.

If you are pregnant, planning to become pregnant, or breastfeeding, inform your doctor. It is essential to discuss the potential benefits and risks of this medication to both you and your baby to make an informed decision.

• Alcohol (including alcohol-containing products like cough syrups, mouthwash) - disulfiram-like reaction (abdominal cramps, nausea, vomiting, headaches, flushing)
• Disulfiram - psychotic reactions (confusion, hallucinations)

• Warfarin and other oral anticoagulants - increased anticoagulant effect (monitor INR/PT)
• Lithium - increased lithium levels and potential for toxicity (monitor lithium levels)
• Busulfan - increased busulfan plasma concentrations and potential for toxicity
• Fluorouracil - increased fluorouracil toxicity

• Cimetidine - decreased metronidazole clearance, leading to increased metronidazole levels
• Phenobarbital, Phenytoin - increased metronidazole metabolism, leading to decreased metronidazole levels
• Cyclosporine - increased cyclosporine levels and potential for toxicity
• Tacrolimus - increased tacrolimus levels and potential for toxicity
• Oral contraceptives - may reduce efficacy of oral contraceptives (use alternative birth control)

• Cholestyramine - may reduce metronidazole absorption (separate administration)

• Nausea
• Vomiting
• Diarrhea
• Metallic taste in mouth
• Headache
• Dizziness
• Peripheral neuropathy (numbness, tingling, weakness)
• Seizures
• Encephalopathy
• Aseptic meningitis
• Rash
• Pruritus
• Vaginal candidiasis (in females)
• Oral candidiasis (thrush)
• Darkening of urine (harmless)

Metronidazole is classified as Pregnancy Category B. While animal studies have shown no evidence of harm, human studies are limited. It is generally considered safe for use during the second and third trimesters when clearly needed. Use during the first trimester should be avoided unless the benefits outweigh the potential risks.

Metronidazole is excreted into breast milk in concentrations similar to maternal plasma. The American Academy of Pediatrics considers it compatible with breastfeeding, but some sources recommend temporary interruption of breastfeeding (e.g., for 12-24 hours after a single 2g dose) or using an alternative drug if possible, due to potential for infant GI upset, metallic taste, or theoretical carcinogenicity.

Dosing is weight-based and varies by indication. Safety and efficacy have been established for certain indications. Close monitoring for adverse effects, especially neurological, is important. Avoid prolonged use.

No specific dose adjustment is typically required based on age alone. However, elderly patients may have reduced hepatic or renal function, which could affect metronidazole clearance. Monitor for adverse effects, particularly neurological symptoms, and adjust dose if severe hepatic or renal impairment is present.

• Metronidazole is highly effective against anaerobic bacteria and protozoa, but not aerobic bacteria.
• The most common side effects are GI upset (nausea, vomiting, diarrhea) and a metallic taste in the mouth.
• Patients must be strongly advised to avoid all alcohol during and for at least 3 days after treatment due to the disulfiram-like reaction.
• Darkening of urine is a common and harmless side effect.
• Neurological side effects (peripheral neuropathy, seizures) are rare but serious and warrant immediate discontinuation.
• For single-dose regimens (e.g., for trichomoniasis), ensure both the patient and their sexual partner(s) are treated simultaneously to prevent reinfection.

• Tinidazole (another nitroimidazole, often used for similar protozoal infections)
• Clindamycin (for anaerobic bacterial infections, bacterial vaginosis)
• Ornidazole (another nitroimidazole, not widely available in US)
• Secnidazole (single-dose nitroimidazole for bacterial vaginosis, trichomoniasis)

If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it's a good idea to check with your pharmacist for more information. If you have any questions or concerns about this medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the overdose, including the medication taken, the amount, and the time it occurred.