Macrobid
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Macrobid is a brand name for the generic drug nitrofurantoin. It is an antibiotic that is used to treat urinary tract infections (UTIs). Macrobid works by killing the bacteria that cause UTIs.
Mechanism of Action
Macrobid (nitrofurantoin) is a synthetic antimicrobial agent that belongs to the nitrofuran class of antibiotics. Nitrofurans exert their antibacterial activity by inhibiting several key enzymatic reactions within the bacterial cell.
Nitrofurantoin is rapidly bactericidal against most strains of Escherichia coli, Enterobacter spp., Klebsiella spp., Enterococcus faecalis, and Staphylococcus aureus. It is also active against some strains of Pseudomonas aeruginosa, Proteus mirabilis, and Citrobacter spp.
Nitrofurantoin is bactericidal because it damages the bacterial cell wall, disrupts DNA synthesis, and inhibits protein synthesis. It also produces reactive oxygen species (ROS) that can damage bacterial DNA and proteins.
Nitrofurantoin is primarily used to treat uncomplicated urinary tract infections (UTIs) caused by susceptible bacteria. It is also used to prevent UTIs in patients who are at high risk for developing recurrent infections.
Macrobid is available in both oral and intravenous formulations. The oral formulation is typically taken twice a day for 5 to 7 days. The intravenous formulation is typically given every 6 to 8 hours for 7 to 10 days.
Pharmacokinetics
Macrobid (nitrofurantoin) is rapidly absorbed from the gastrointestinal tract after oral administration. Peak plasma concentrations are reached within 1 to 2 hours.
Absorption
Macrobid (nitrofurantoin) is rapidly and almost completely absorbed from the gastrointestinal tract after oral administration. Peak plasma concentrations are reached within 1 to 2 hours.
The absorption of Macrobid is not affected by food. However, the absorption of Macrobid may be decreased by antacids or dairy products.
The bioavailability of Macrobid is approximately 50%. This means that only about half of the dose of Macrobid that is taken orally is absorbed into the bloodstream.
Macrobid is distributed throughout the body, including the kidneys, liver, lungs, and urine. It is also distributed into breast milk.
The protein binding of Macrobid is approximately 60%. This means that about 60% of Macrobid in the bloodstream is bound to plasma proteins.
Macrobid is metabolized in the liver. The metabolites of Macrobid are excreted in the urine.
The elimination half-life of Macrobid is approximately 20 hours.
Distribution
Macrobid (nitrofurantoin) is distributed throughout the body, including the kidneys, liver, lungs, and urine. It is also distributed into breast milk.
The apparent volume of distribution of Macrobid is approximately 0.3 to 0.7 liters per kilogram (L/kg). This means that Macrobid is distributed into a volume of fluid that is about 30% to 70% of the body weight.
Macrobid is approximately 60% bound to plasma proteins. This means that about 60% of Macrobid in the bloodstream is bound to plasma proteins.
Macrobid crosses the placenta and is distributed into fetal tissues. The concentration of Macrobid in fetal tissues is approximately 50% of the maternal plasma concentration.
Macrobid is also distributed into breast milk. The concentration of Macrobid in breast milk is approximately 25% of the maternal plasma concentration.
Metabolism
Macrobid (nitrofurantoin) is metabolized in the liver. The metabolites of Macrobid are excreted in the urine.
The major metabolite of Macrobid is 4-amino-3-nitrophenylglyoxylic acid (AGN). AGN is approximately 10% as active as Macrobid against Escherichia coli.
Other metabolites of Macrobid include 3-amino-2-oxazolidinone (AOZ) and 1-aminohydantoin (AHD). AOZ and AHD are not active against E. coli.
The metabolism of Macrobid is decreased in patients with renal impairment. This can lead to increased plasma concentrations of Macrobid and its metabolites.
The metabolism of Macrobid is also decreased in patients who are taking Probenecid. Probenecid inhibits the renal tubular secretion of Macrobid, which can lead to increased plasma concentrations of Macrobid and its metabolites.
Excretion
Macrobid (nitrofurantoin) is excreted in the urine. Approximately 40% of the dose of Macrobid that is taken orally is excreted in the urine as unchanged drug.
The elimination half-life of Macrobid is approximately 20 hours. This means that it takes about 20 hours for the plasma concentration of Macrobid to decrease by half.
The elimination of Macrobid is decreased in patients with renal impairment. This can lead to increased plasma concentrations of Macrobid and its metabolites.
Macrobid is also excreted in breast milk. The concentration of Macrobid in breast milk is approximately 25% of the maternal plasma concentration.
Pharmacodynamics
Macrobid (nitrofurantoin) is a synthetic antimicrobial agent that belongs to the nitrofuran class of antibiotics. Nitrofurans exert their antibacterial activity by inhibiting several key enzymatic reactions within the bacterial cell.
Nitrofurantoin is bactericidal because it damages the bacterial cell wall, disrupts DNA synthesis, and inhibits protein synthesis. It also produces reactive oxygen species (ROS) that can damage bacterial DNA and proteins.
Nitrofurantoin is primarily used to treat uncomplicated urinary tract infections (UTIs) caused by susceptible bacteria. It is also used to prevent UTIs in patients who are at high risk for developing recurrent infections.
The bactericidal activity of Macrobid is concentration-dependent. This means that the higher the concentration of Macrobid in the urine, the greater the bactericidal activity.
Macrobid is most active against Escherichia coli, which is the most common cause of UTIs. It is also active against Enterobacter spp., Klebsiella spp., Enterococcus faecalis, and Staphylococcus aureus.
Clinical Efficacy
Macrobid (nitrofurantoin) is a well-established and effective antibiotic for the treatment and prevention of uncomplicated urinary tract infections (UTIs). It has been shown to be effective in both adults and children.
In adults, Macrobid has been shown to be effective in treating acute uncomplicated cystitis and pyelonephritis. It is also effective in preventing recurrent UTIs in patients who have a history of recurrent infections.
In children, Macrobid has been shown to be effective in treating acute uncomplicated cystitis. It is also effective in preventing recurrent UTIs in children who have a history of recurrent infections.
Macrobid is generally well-tolerated. The most common side effects are gastrointestinal symptoms, such as nausea, vomiting, and diarrhea. These side effects are usually mild and transient.
Macrobid is contraindicated in patients with a history of hypersensitivity to nitrofurantoin or other nitrofurans. It is also contraindicated in patients with severe renal impairment or hepatic impairment.
Dosage and Administration
Macrobid (nitrofurantoin) is available in both oral and intravenous formulations.
Adults
The usual adult dosage of Macrobid (nitrofurantoin) for the treatment of acute uncomplicated urinary tract infections (UTIs) is 100 mg orally every 6 hours for 7 to 10 days.
For the prevention of recurrent UTIs, the usual adult dosage of Macrobid is 100 mg orally at bedtime.
The dosage of Macrobid may be adjusted in patients with renal impairment. The dosage should be reduced in patients with a creatinine clearance of less than 60 mL/min.
Macrobid should be taken with food to reduce the risk of gastrointestinal side effects.
Macrobid should not be taken for more than 14 days without the supervision of a physician.
Children
The usual pediatric dosage of Macrobid (nitrofurantoin) for the treatment of acute uncomplicated urinary tract infections (UTIs) is 5 to 7 mg/kg orally every 6 hours for 7 to 10 days.
For the prevention of recurrent UTIs, the usual pediatric dosage of Macrobid is 1 to 2 mg/kg orally at bedtime.
The dosage of Macrobid may be adjusted in children with renal impairment. The dosage should be reduced in children with a creatinine clearance of less than 60 mL/min.
Macrobid should be taken with food to reduce the risk of gastrointestinal side effects.
Macrobid should not be taken for more than 14 days without the supervision of a physician.
Contraindications
Macrobid (nitrofurantoin) is contraindicated in patients with⁚
- A history of hypersensitivity to nitrofurantoin or other nitrofurans
- Severe renal impairment (creatinine clearance less than 30 mL/min)
- Hepatic impairment
- G6PD deficiency
- Infants less than 1 month old
Macrobid should be used with caution in patients with⁚
- Mild to moderate renal impairment (creatinine clearance 30 to 60 mL/min)
- Glucose-6-phosphate dehydrogenase (G6PD) deficiency
- Diabetes mellitus
- Electrolyte imbalance
- Vitamin B12 deficiency
Precautions
Macrobid (nitrofurantoin) should be used with caution in patients with⁚
- Mild to moderate renal impairment (creatinine clearance 30 to 60 mL/min)
- Glucose-6-phosphate dehydrogenase (G6PD) deficiency
- Diabetes mellitus
- Electrolyte imbalance
- Vitamin B12 deficiency
Macrobid can cause hemolytic anemia in patients with G6PD deficiency. The risk of hemolytic anemia is increased in patients who are also taking other medications that can cause hemolysis, such as antimalarials, sulfonamides, and quinolones.
Macrobid can cause peripheral neuropathy, especially in patients who are taking the drug for long periods of time or who have a history of peripheral neuropathy.
Macrobid can cause pulmonary fibrosis, especially in patients who are taking the drug for long periods of time or who have a history of pulmonary fibrosis.
Warnings
Macrobid (nitrofurantoin) can cause serious side effects, including⁚
- Hemolytic anemia in patients with G6PD deficiency
- Peripheral neuropathy
- Pulmonary fibrosis
- Hepatitis
- Liver failure
- Death
The risk of these side effects is increased in patients who are taking Macrobid for long periods of time or who have a history of these conditions.
Macrobid should be used only when other antibiotics are not effective or are not tolerated.
Patients taking Macrobid should be closely monitored for side effects, especially if they have a history of G6PD deficiency, peripheral neuropathy, pulmonary fibrosis, hepatitis, or liver failure.
Drug Interactions
Macrobid (nitrofurantoin) can interact with other medications, including⁚- Anticoagulants⁚ Macrobid can increase the effects of anticoagulants, such as warfarin.
- Antiplatelet agents⁚ Macrobid can increase the effects of antiplatelet agents, such as aspirin and clopidogrel.
- Probenecid⁚ Probenecid can decrease the excretion of Macrobid, which can lead to increased plasma concentrations of Macrobid.
- Magnesium trisilicate⁚ Magnesium trisilicate can decrease the absorption of Macrobid.
- Sodium bicarbonate⁚ Sodium bicarbonate can increase the excretion of Macrobid, which can lead to decreased plasma concentrations of Macrobid.
It is important to tell your doctor about all of the medications you are taking, including prescription and over-the-counter medications, vitamins, and herbal supplements.
Adverse Effects
Macrobid (nitrofurantoin) can cause side effects, including⁚
Common
The most common side effects of Macrobid (nitrofurantoin) include⁚
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain
- Headache
- Dizziness
- Fatigue
- Rash
- Itching
These side effects are usually mild and transient. They typically occur within the first few days of treatment and resolve within a few days after stopping the drug.
Less Common
Less common side effects of Macrobid (nitrofurantoin) include⁚
- Peripheral neuropathy
- Pulmonary fibrosis
- Hepatitis
- Liver failure
- Hemolytic anemia
- Aplastic anemia
- Agranulocytosis
- Thrombocytopenia
- Leukopenia
- Eosinophilia
These side effects are more likely to occur in patients who are taking Macrobid for long periods of time or who have a history of these conditions.
Rare
Rare side effects of Macrobid (nitrofurantoin) include⁚
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
- Acute renal failure
- Chronic renal failure
- Interstitial nephritis
- Tubulointerstitial nephritis
- Nephrotic syndrome
- Death
These side effects are very rare, but they can be serious. If you experience any of these side effects, stop taking Macrobid and seek medical attention immediately.
Overdose
Overdosage of Macrobid (nitrofurantoin) can cause serious side effects, including⁚
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain
- Headache
- Dizziness
- Fatigue
- Rash
- Itching
- Peripheral neuropathy
- Pulmonary fibrosis
- Hepatitis
- Liver failure
- Hemolytic anemia
- Aplastic anemia
- Agranulocytosis
- Thrombocytopenia
- Leukopenia
- Eosinophilia
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
- Acute renal failure
- Chronic renal failure
- Interstitial nephritis
- Tubulointerstitial nephritis
- Nephrotic syndrome
- Death
If you suspect that someone has overdosed on Macrobid, call your local poison control center or seek medical attention immediately.
Storage and Handling
Macrobid (nitrofurantoin) should be stored at room temperature (20 to 25°C) in a dry place. Protect from light.
Macrobid should not be stored in a bathroom or other areas where it could be exposed to moisture or heat.
Keep Macrobid out of reach of children and pets.
Do not use Macrobid after the expiration date on the package.
If you have any questions about the storage and handling of Macrobid, talk to your pharmacist.
Patient Information
Macrobid (nitrofurantoin) is an antibiotic that is used to treat urinary tract infections (UTIs).
Macrobid is available in both oral and intravenous formulations. The oral formulation is typically taken twice a day for 5 to 7 days. The intravenous formulation is typically given every 6 to 8 hours for 7 to 10 days.
Macrobid should be taken with food to reduce the risk of gastrointestinal side effects.
Macrobid should not be taken for more than 14 days without the supervision of a physician.
Common side effects of Macrobid include nausea, vomiting, diarrhea, abdominal pain, headache, dizziness, fatigue, rash, and itching.
Rare but serious side effects of Macrobid include peripheral neuropathy, pulmonary fibrosis, hepatitis, liver failure, hemolytic anemia, aplastic anemia, agranulocytosis, thrombocytopenia, leukopenia, eosinophilia, Stevens-Johnson syndrome, toxic epidermal necrolysis, acute renal failure, chronic renal failure, interstitial nephritis, tubulointerstitial nephritis, nephrotic syndrome, and death.
If you experience any side effects from Macrobid, talk to your doctor.
Availability
Macrobid (nitrofurantoin) is available as a generic medication and as a brand-name medication.
The generic medication is available in both oral and intravenous formulations.
The brand-name medication is available only in an oral formulation.
Macrobid is available in the following strengths⁚
- 50 mg capsules
- 100 mg capsules
- 150 mg capsules
- 300 mg capsules
- 100 mg/5 mL oral suspension
- 100 mg/10 mL intravenous injection
Macrobid is available in most pharmacies.
Cost
The cost of Macrobid (nitrofurantoin) varies depending on the dosage and formulation.
The average cost of a 100 mg capsule is $4.
The average cost of a 100 mg/5 mL oral suspension is $10.
The average cost of a 100 mg/10 mL intravenous injection is $15.
Macrobid is available as a generic medication, which is typically less expensive than the brand-name medication.
There are also a number of patient assistance programs available to help reduce the cost of Macrobid for low-income patients.
If you are uninsured or underinsured, you may be able to get Macrobid for free or at a reduced cost through a patient assistance program.
Macrobid (nitrofurantoin) is a safe and effective antibiotic for the treatment and prevention of uncomplicated urinary tract infections (UTIs). It is available in both oral and intravenous formulations and is generally well-tolerated.
The most common side effects of Macrobid are gastrointestinal symptoms, such as nausea, vomiting, and diarrhea. These side effects are usually mild and transient.
Macrobid is contraindicated in patients with a history of hypersensitivity to nitrofurantoin or other nitrofurans, severe renal impairment, hepatic impairment, G6PD deficiency, and infants less than 1 month old.
Macrobid should be used with caution in patients with mild to moderate renal impairment, G6PD deficiency, diabetes mellitus, electrolyte imbalance, and vitamin B12 deficiency.
Serious side effects of Macrobid are rare, but they can include peripheral neuropathy, pulmonary fibrosis, hepatitis, liver failure, hemolytic anemia, aplastic anemia, agranulocytosis, thrombocytopenia, leukopenia, eosinophilia, Stevens-Johnson syndrome, toxic epidermal necrolysis, acute renal failure, chronic renal failure, interstitial nephritis, tubulointerstitial nephritis, nephrotic syndrome, and death.
If you experience any side effects from Macrobid, talk to your doctor.