Macrodantin 25mg Capsules
It is used to treat or prevent a urinary tract infection (UTI).
Drug Class
Urinary Anti-infective
Pharmacologic Class
Nitrofuran derivative, Antibacterial
Pregnancy Category
Category B (Contraindicated at term)
FDA Approved
Jan 1967
DEA Schedule
Not Controlled
Overview
What is this medicine?
Nitrofurantoin is an antibiotic used to treat and prevent urinary tract infections (UTIs). It works by stopping the growth of bacteria in the urine. It is important to take this medication exactly as prescribed, usually with food, to help it work best and reduce stomach upset.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Take your medication with food to help your body absorb it properly. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
It's also important to stay hydrated by drinking plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake. However, do not take antacids that contain magnesium trisilicate while taking this medication, as they may interact with it.
Storing and Disposing of Your Medication
To keep your medication effective and safe, store it at room temperature in a dry place, away from the bathroom. Keep all medications out of the reach of children and pets to avoid accidents. When you're finished with your medication or it expires, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your doctor or pharmacist. If you're unsure about how to dispose of your medication, ask your pharmacist for guidance. You may also want to check if there are any drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for a missed one.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Take your medication with food to help your body absorb it properly. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.
It's also important to stay hydrated by drinking plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake. However, do not take antacids that contain magnesium trisilicate while taking this medication, as they may interact with it.
Storing and Disposing of Your Medication
To keep your medication effective and safe, store it at room temperature in a dry place, away from the bathroom. Keep all medications out of the reach of children and pets to avoid accidents. When you're finished with your medication or it expires, dispose of it properly. Do not flush it down the toilet or pour it down the drain unless instructed to do so by your doctor or pharmacist. If you're unsure about how to dispose of your medication, ask your pharmacist for guidance. You may also want to check if there are any drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for a missed one.
Lifestyle & Tips
- Take with food or milk to improve absorption and reduce stomach upset.
- Drink plenty of fluids unless otherwise directed by your doctor.
- Complete the full course of medication, even if symptoms improve, to prevent the infection from returning and to reduce the risk of antibiotic resistance.
- Urine may turn brown or orange while taking this medication; this is a harmless side effect.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
25 mg to 100 mg four times a day for 7 days (for acute uncomplicated UTI). For long-term suppression, 50-100 mg once daily at bedtime.
Dose Range:
25 - 100 mg
Condition-Specific Dosing:
acute_uncomplicated_uti:
50-100 mg four times a day for 7 days
long_term_suppression:
50-100 mg once daily at bedtime
Pediatric Dosing
Neonatal:
Contraindicated in infants less than one month of age.
Infant:
Contraindicated in infants less than one month of age. For infants >1 month and children: 5-7 mg/kg/day in four divided doses.
Child:
5-7 mg/kg/day in four divided doses (maximum 400 mg/day).
Adolescent:
5-7 mg/kg/day in four divided doses (maximum 400 mg/day) or adult dose of 50-100 mg four times a day.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment needed if CrCl > 60 mL/min.
Moderate:
Contraindicated if CrCl < 60 mL/min due to lack of efficacy and increased risk of toxicity (e.g., peripheral neuropathy).
Severe:
Contraindicated if CrCl < 60 mL/min.
Dialysis:
Contraindicated. Not effectively removed by dialysis.
Hepatic Impairment:
Mild:
No specific adjustment, but use with caution.
Moderate:
No specific adjustment, but use with caution and monitor liver function.
Severe:
No specific adjustment, but use with caution and monitor liver function. Increased risk of hepatotoxicity.
Pharmacology
Mechanism of Action
Nitrofurantoin is reduced by bacterial flavoproteins to reactive intermediates that inactivate or damage bacterial ribosomal proteins, DNA, RNA, and other macromolecules. This leads to inhibition of bacterial growth and cell death. It is bactericidal in urine at therapeutic concentrations.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 40-50% (increased with food)
Tmax:
Approximately 0.5-1 hour
FoodEffect:
Food significantly increases the absorption and bioavailability of nitrofurantoin, and prolongs its therapeutic concentration in urine. It also helps minimize gastrointestinal upset.
Distribution:
Vd:
Approximately 0.8 L/kg
ProteinBinding:
Approximately 60%
CnssPenetration:
Limited
Elimination:
HalfLife:
Approximately 0.3-1 hour
Clearance:
Rapid renal clearance
ExcretionRoute:
Primarily renal (glomerular filtration and tubular secretion)
Unchanged:
20-40% excreted unchanged in urine
Pharmacodynamics
OnsetOfAction:
Rapid, within hours of first dose
PeakEffect:
Urinary concentrations peak within 1-3 hours
DurationOfAction:
Approximately 6-8 hours (requires frequent dosing)
Safety & Warnings
Side Effects
Serious Side Effects: Seek Medical Help Immediately
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. 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
Note: In rare cases, allergic reactions can be fatal.
Signs of pancreatitis (pancreas problem), such as:
+ Severe stomach pain
+ Severe back pain
+ Severe upset stomach or vomiting
Signs of lupus, such as:
+ Rash on the cheeks or other body parts
+ Easy sunburn
+ Muscle or joint pain
+ Chest pain or shortness of breath
+ Swelling in the arms or legs
Inability to control eye movements
Diarrhea, especially if it is severe, bloody, or watery (may be a sign of C. diff-associated diarrhea, a potentially life-threatening condition)
Liver problems, such as:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Note: Liver problems can be fatal.
Nerve problems, such as:
+ Burning sensation
+ Numbness
+ Tingling
Note: Nerve problems can be severe, permanent, or fatal, especially in people with kidney problems, anemia, diabetes, electrolyte problems, or low vitamin B levels.
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 or seek medical attention if they bother you or do not go away:
Headache
Upset stomach or vomiting
Decreased appetite
Stomach pain or diarrhea
Dizziness, drowsiness, tiredness, or weakness
Hair loss (usually reversible after stopping the medication)
Brown-colored urine (harmless and temporary)
Reporting Side Effects
If you have questions about side effects or experience any side effects not listed here, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. 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
Note: In rare cases, allergic reactions can be fatal.
Signs of pancreatitis (pancreas problem), such as:
+ Severe stomach pain
+ Severe back pain
+ Severe upset stomach or vomiting
Signs of lupus, such as:
+ Rash on the cheeks or other body parts
+ Easy sunburn
+ Muscle or joint pain
+ Chest pain or shortness of breath
+ Swelling in the arms or legs
Inability to control eye movements
Diarrhea, especially if it is severe, bloody, or watery (may be a sign of C. diff-associated diarrhea, a potentially life-threatening condition)
Liver problems, such as:
+ Dark urine
+ Tiredness
+ Decreased appetite
+ Upset stomach or stomach pain
+ Light-colored stools
+ Vomiting
+ Yellow skin or eyes
Note: Liver problems can be fatal.
Nerve problems, such as:
+ Burning sensation
+ Numbness
+ Tingling
Note: Nerve problems can be severe, permanent, or fatal, especially in people with kidney problems, anemia, diabetes, electrolyte problems, or low vitamin B levels.
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 or seek medical attention if they bother you or do not go away:
Headache
Upset stomach or vomiting
Decreased appetite
Stomach pain or diarrhea
Dizziness, drowsiness, tiredness, or weakness
Hair loss (usually reversible after stopping the medication)
Brown-colored urine (harmless and temporary)
Reporting Side Effects
If you have questions about side effects or experience any side effects not listed here, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- New or worsening cough, shortness of breath, or chest pain (signs of lung problems)
- Unusual fatigue, nausea, vomiting, dark urine, yellowing of skin or eyes (jaundice), or abdominal pain (signs of liver problems)
- Tingling, numbness, or weakness in the hands or feet (signs of nerve damage)
- Severe diarrhea (especially if watery or bloody)
- Fever, chills, body aches (signs of a new infection or severe reaction)
- Rash, itching, swelling of the face/tongue/throat, severe dizziness, trouble breathing (signs of an allergic reaction)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following conditions before starting this medication:
Any allergies you have, including allergies to this drug, its components, or other substances, such as foods or medications. Be sure to describe the symptoms you experienced.
Kidney disease, as this may affect how your body processes the medication.
Difficulty urinating, as this could be a sign of an underlying condition that may interact with the medication.
Previous liver problems caused by this medication, as this may increase your risk of further liver damage.
Pregnancy, especially if you are 38 weeks or more pregnant, as this medication may affect the fetus.
Special Considerations for Children:
If the patient is a child under 1 month of age, do not administer this medication, as it is not approved for use in this age group.
Additional Important Information:
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. This will help ensure that it is safe to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without consulting your doctor first.
It is essential to inform your doctor about the following conditions before starting this medication:
Any allergies you have, including allergies to this drug, its components, or other substances, such as foods or medications. Be sure to describe the symptoms you experienced.
Kidney disease, as this may affect how your body processes the medication.
Difficulty urinating, as this could be a sign of an underlying condition that may interact with the medication.
Previous liver problems caused by this medication, as this may increase your risk of further liver damage.
Pregnancy, especially if you are 38 weeks or more pregnant, as this medication may affect the fetus.
Special Considerations for Children:
If the patient is a child under 1 month of age, do not administer this medication, as it is not approved for use in this age group.
Additional Important Information:
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. This will help ensure that it is safe to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without consulting your doctor first.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
If you have a deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD), you may be at a higher risk of developing anemia. Individuals of African, South Asian, Middle Eastern, and Mediterranean descent are more likely to have low G6PD levels.
If you have diabetes and regularly test your urine for glucose, consult with your doctor to determine the most suitable testing methods for you.
Do not take this medication for longer than prescribed, as this may increase the risk of a second infection.
Although rare, this medication can cause severe and potentially life-threatening lung problems, particularly in individuals taking it for 6 months or longer. These lung problems can occur without warning signs. If you are taking this medication long-term, your doctor will monitor your lung function. Immediately contact your doctor if you experience symptoms such as fever, chills, chest pain, an abnormal cough, difficulty breathing, or other respiratory problems.
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, discuss the potential benefits and risks of this medication with your doctor to ensure the best outcome for you and your baby.
If you have a deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD), you may be at a higher risk of developing anemia. Individuals of African, South Asian, Middle Eastern, and Mediterranean descent are more likely to have low G6PD levels.
If you have diabetes and regularly test your urine for glucose, consult with your doctor to determine the most suitable testing methods for you.
Do not take this medication for longer than prescribed, as this may increase the risk of a second infection.
Although rare, this medication can cause severe and potentially life-threatening lung problems, particularly in individuals taking it for 6 months or longer. These lung problems can occur without warning signs. If you are taking this medication long-term, your doctor will monitor your lung function. Immediately contact your doctor if you experience symptoms such as fever, chills, chest pain, an abnormal cough, difficulty breathing, or other respiratory problems.
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, discuss the potential benefits and risks of this medication with your doctor to ensure the best outcome for you and your baby.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain
- Headache
- Dizziness
- Peripheral neuropathy (tingling, numbness)
- Hemolytic anemia (in susceptible individuals)
What to Do:
In case of overdose, seek immediate medical attention or call a Poison Control Center at 1-800-222-1222. Treatment is generally supportive, including gastric lavage if recent ingestion, and monitoring of vital signs and symptoms.
Drug Interactions
Major Interactions
- Probenecid
- Sulfinpyrazone
Moderate Interactions
- Antacids (containing magnesium trisilicate)
- Quinolone antibiotics (e.g., ciprofloxacin, levofloxacin)
- Oral typhoid vaccine (Ty21a)
Minor Interactions
- Oral contraceptives (theoretical, not well-established)
Monitoring
Baseline Monitoring
Renal function (CrCl)
Rationale: To ensure adequate renal clearance and avoid toxicity, as nitrofurantoin is contraindicated in significant renal impairment.
Timing: Prior to initiation of therapy.
Liver function tests (ALT, AST, bilirubin)
Rationale: Baseline assessment, especially if prolonged therapy is anticipated or patient has pre-existing liver disease, due to risk of hepatotoxicity.
Timing: Prior to initiation of therapy.
Routine Monitoring
Signs and symptoms of pulmonary toxicity (cough, dyspnea, chest pain)
Frequency: Daily, throughout therapy and up to several weeks after discontinuation.
Target: Absence of symptoms
Action Threshold: Immediate discontinuation if symptoms occur; consider chest X-ray and pulmonary function tests.
Signs and symptoms of hepatotoxicity (fatigue, nausea, dark urine, jaundice)
Frequency: Periodically, especially with long-term therapy.
Target: Absence of symptoms; normal LFTs
Action Threshold: Immediate discontinuation if symptoms or significant LFT elevations occur.
Signs and symptoms of peripheral neuropathy (tingling, numbness, weakness)
Frequency: Daily, throughout therapy.
Target: Absence of symptoms
Action Threshold: Immediate discontinuation if symptoms occur, as it may be irreversible.
Complete Blood Count (CBC) with differential
Frequency: Periodically, especially with long-term therapy or in patients with G6PD deficiency.
Target: Normal cell counts
Action Threshold: Discontinue if hemolytic anemia or other blood dyscrasias develop.
Symptom Monitoring
- Cough
- Dyspnea
- Chest pain
- Fever
- Chills
- Fatigue
- Nausea
- Anorexia
- Dark urine
- Jaundice
- Tingling
- Numbness
- Weakness in extremities
- Severe diarrhea
- Abdominal pain
- Rash
- Itching
Special Patient Groups
Pregnancy
Generally considered Category B for most of pregnancy. However, it is contraindicated at term (38-42 weeks gestation) and during labor and delivery due to the risk of hemolytic anemia in the neonate, especially in infants with immature enzyme systems (e.g., G6PD deficiency).
Trimester-Specific Risks:
First Trimester:
Generally considered low risk, Category B.
Second Trimester:
Generally considered low risk, Category B.
Third Trimester:
Contraindicated at term (38-42 weeks) and during labor/delivery due to risk of neonatal hemolytic anemia.
Lactation
Excreted into breast milk in very small amounts. Generally considered compatible with breastfeeding, but caution is advised. Avoid use in infants less than one month of age, or in infants with known or suspected G6PD deficiency, due to the theoretical risk of hemolytic anemia.
Infant Risk:
Low risk for most healthy, full-term infants older than 1 month. Moderate concern (L3) for infants <1 month or G6PD deficient infants.
Pediatric Use
Contraindicated in infants less than one month of age due to the risk of hemolytic anemia secondary to immature enzyme systems. Use with caution in older pediatric patients, monitoring for adverse effects.
Geriatric Use
Increased risk of adverse effects, particularly pulmonary toxicity, hepatotoxicity, and peripheral neuropathy. Renal function should be carefully assessed, as nitrofurantoin is contraindicated in patients with CrCl < 60 mL/min, which is more common in the elderly. Use the lowest effective dose for the shortest duration necessary.
Clinical Information
Clinical Pearls
- Nitrofurantoin is a first-line agent for uncomplicated lower urinary tract infections (UTIs) due to its excellent activity against common uropathogens like E. coli and low rates of resistance.
- It is not effective for pyelonephritis or systemic infections because it achieves very low systemic concentrations and does not penetrate renal tissue well.
- Always take with food to enhance absorption and reduce gastrointestinal side effects.
- Counsel patients about potential urine discoloration (brown/orange) which is harmless.
- Emphasize the importance of reporting any signs of lung, liver, or nerve problems immediately, as these can be serious and potentially irreversible.
- Avoid in patients with significant renal impairment (CrCl < 60 mL/min) due to reduced efficacy and increased risk of toxicity.
Alternative Therapies
- Trimethoprim/sulfamethoxazole (Bactrim)
- Fosfomycin
- Pivmecillinam (not available in US)
- Fluoroquinolones (e.g., ciprofloxacin, levofloxacin) - generally reserved for complicated UTIs or when other options are not suitable due to resistance concerns.
- Beta-lactam antibiotics (e.g., amoxicillin/clavulanate, cephalexin) - often less effective for uncomplicated UTIs due to higher resistance rates.
Cost & Coverage
Average Cost:
$20 - $60 per 30 capsules (25mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 or Tier 2 (Generic)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure your safety, 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. If you have any questions or concerns about this medication, don't hesitate to discuss them with 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 information about the medication taken, the amount, and the time it happened.