Nitrofurantoin mono-MCR 100 mg is a commonly used antibiotic to treat and prevent simple urinary tract infections (UTIs). This first-line antibiotic has been used effectively by millions to treat bacterial bladder and lower urinary tract infections (UTIs). Knowing how it works, how to take it, possible side effects and precautions will help ensure its safe and effective use.
What is Nitrofurantoin mono-MCR 100 mg?
Nitrofurantoin mono-MCR 100 mg is a member of the nitrofuran antibiotics. The “mono-MCR” stands for monohydrate/macrocrystalline, which is a blend of two crystalline forms of nitrofurantoin. This combination allows the drug to be released more slowly and be better tolerated in the gut than older products. Available in 100 mg capsules, the drug can be taken once or twice a day, depending on the individual patient’s needs.
Nitrofurantoin is one of the few antibiotics that is highly concentrated in the urine. This allows it to reach the site of infection (the bladder and urine) and kill bacteria while limiting the antibiotic’s presence in the rest of the body and the spread of antibiotic resistance.
How this Antibiotic Works
The drug nitrofurantoin has several modes of action, making resistance by bacteria harder to achieve. It is activated by bacterial enzymes once inside the bacterial cell. The activated drug then interferes with bacterial DNA, RNA, cell wall formation and other essential bacterial processes. By targeting several different processes, nitrofurantoin is effective against many of the common pathogens that cause UTIs, such as Escherichia coli, Enterococcus faecalis, Staphylococcus saprophyticus and Klebsiella species.
However, nitrofurantoin does not work on most Proteus, Pseudomonas or Serratia species, so it’s important to consult a health care professional before treating a suspected infection.
Indications and Dosage
Doctors prescribe nitrofurantoin mono-MCR 100 mg for:
- Acute cystitis (uncomplicated UTIs) in women and children 12 years and older
- Prophylaxis (prevention) against recurrent UTIs in patients with a high risk
- Prophylaxis following urologic surgery in some indications
Acute UTI dosing regimen:
- Typical: One 100 mg capsule twice a day for 5 days
- Alternative: One 100 mg capsule every 6 hours for 7 days (used less frequently)
For UTI prevention:
- One 100 mg capsule every night at bedtime, typically for 3-6 months
The full course should be taken, even if you feel better. This could result in the bacteria not being fully killed and a relapse.
Warnings and Precautions
Nitrofurantoin mono-MCR 100 mg isn’t for everyone. Avoid using this drug if you:
- Are severely renal diseased (creatinine clearance of less than 30 mL/min)
- Are in the third trimester of pregnancy (less than 2-4 weeks to term) (risk of hemolytic anemia in the fetus)
- Are allergic to nitrofurantoin (or other nitrofurans)
- Have acute porphyria
- Are severely diseased or have cholestatic jaundice after nitrofurantoin
Use cautiously in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency, as they may develop hemolytic anemia.
Common Side Effects
Nitrofurantoin is generally well tolerated, but can cause:
Gastrointestinal (most common):
- Nausea and vomiting (can be avoided by taking with food)
- Loss of appetite
- Diarrhea or abdominal pain
Neurological:
- Headache
- Dizziness or drowsiness
Other:
- Brown-coloured urine (harmless and temporary)
Serious (but rare) side effects that need immediate medical care include:
- Peripheral neuropathy (numbness/tingling of hands or feet)
- Allergic reactions (rash, itching, short of breath)
- Liver disease (jaundice, tea coloured urine, fatigue)
- Lung injury (fever, chills, cough, chest pain)
Drug Interactions to Remember
Nitrofurantoin mono-MCR 100 mg has several drug interactions:
- Antacids containing magnesium trisilicate – decrease absorption
- Probenecid or sulfinpyrazone – reduced excretion, risk of toxicity
- Quinolone antibiotics – may be antagonised
- Typhoid vaccine – decrease vaccine effectiveness
Always tell your doctor about all the medications, supplements and herbs you are taking.
Safety During Pregnancy and Breastfeeding
Nitrofurantoin can be used safely in the first and second trimesters of pregnancy, but should be avoided late in pregnancy (38-42 weeks of gestation) because of the risk of infant hemolysis. It can be safely used while breastfeeding healthy full-term babies. Only take medications during pregnancy and while breastfeeding after consulting with your obstetrician.
When to See a Doctor
If you have any of the following symptoms, see your doctor right away:
- Fever or chills that won’t go away
- New or worsened flank or back pain
- Blood in your urine
- Severe diarrhoea (especially bloody) – possible Clostridioides difficile
- Signs of an allergic reaction
- Bruising or bleeding for no reason
Final Thoughts
Nitrofurantoin mono-MCR 100 mg continues to play a vital role in treating UTIs because it is specific, has low resistance and is generally safe if used correctly. Adhere to your doctor’s guidelines and understand the possible side effects to get the most benefit from this potent antibiotic. Store at room temperature, keep away from moisture and heat and out of the reach of children.
You may also read nowitstrend.
