macrobid
Macrobid is a combination medicine containing Nitrofurantoin, Nitrofurantoin, and Macrocrystalline.
Nitrofurantoin and Nitrofurantoin, Macrocrystalline · by Almatica
Key facts
- Active ingredient
- Nitrofurantoin and Nitrofurantoin, Macrocrystalline
- Form
- Capsule
- Strength
- Nitrofurantoin 75MG; NITROFURANTOIN, Macrocrystalline 25MG
- Type
- Prescription (Rx)
- Brand or generic
- Brand-name
- Manufacturer
- Almatica
- Half-life
- about 20 minutes (roughly 0.3 hours) for the parent drug in adults with normal kidney function (how long it stays in your system)
- What the pharmacy pays
- ~$2.14 per ml — not your price
- FDA application
- NDA020064
What is Macrobid?
From the FDA label:Nitrofurantoin is an antibacterial agent specific for urinary tract infections. Nitrofurantoin capsules, USP (monohydrate/macrocrystals) is a hard gelatin capsule. Each capsule contains 100 mg of nitrofurantoin in the form of 25 mg of nitrofurantoin macrocrystals and 75 mg of nitrofurantoin monohydrate. The chemical name of nitrofurantoin macrocrystals is 1-[[[5-nitro-2-furanyl]methylene] amino]-2,4-imidazolidinedione. The chemical structure is the following: Molecular Weight: 238.16 The chemical name of nitrofurantoin monohydrate is 1-[[[5-nitro-2-furanyl]methylene] amino]-2,4- imidazolidinedione monohydrate. The chemical structure is the following: Molecular Weight: 256.17 Inactive Ingredients: Each capsule contains carbomer 934P, corn starch, compressible sugar, D&C Yellow No. 10, edible gray ink, FD&C Blue No. 1, FD&C Red No. 40, gelatin, lactose, magnesium stearate, povidone, talc, and titanium dioxide. Meets USP Dissolution Test 8.
How to use
Nitrofurantoin capsules (monohydrate/macrocrystals) should be taken with food. Adults and Pediatric Patients Over 12 Years : One 100 mg capsule every 12 hours for seven days.
Side effects
In clinical trials of nitrofurantoin capsules (monohydrate/macrocrystals), the most frequent clinical adverse events that were reported as possibly or probably drug-related were nausea (8%), headache (6%), and flatulence (1.5%). Additional clinical adverse events reported as possibly or probably drug-related occurred in less than 1% of patients studied and are listed below within each body system in order of decreasing frequency: Gastrointestinal : Diarrhea, dyspepsia, abdominal pain, constipation, emesis Neurologic : Dizziness, drowsiness, amblyopia Respiratory: Acute pulmonary hypersensitivity reaction (see WARNINGS ) Allergic: Pruritus, urticaria Dermatologic : Alopecia Miscellaneous : Fever, chills, malaise The following additional clinical adverse events have been reported with the use of nitrofurantoin: Gastrointestinal: Sialadenitis, pancreatitis. There have been sporadic reports of pseudomembranous colitis with the use of nitrofurantoin. The onset of pseudomembranous colitis symptoms may occur during or after antimicrobial treatment. (See WARNINGS .) Neurologic: Peripheral neuropathy, which may become severe or irreversible, has occurred. Fatalities have been reported. Conditions such as renal impairment (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine), anemia, diabetes mellitus, electrolyte imbalance, vitamin B…
Warnings
Important safety information
Pulmonary reactions: ACUTE, SUBACUTE, OR CHRONIC PULMONARY REACTIONS HAVE BEEN OBSERVED IN PATIENTS TREATED WITH NITROFURANTOIN. IF THESE REACTIONS OCCUR, NITROFURANTOIN CAPSULES (MONOHYDRATE/MACROCRYSTALS) SHOULD BE DISCONTINUED AND APPROPRIATE MEASURES TAKEN. REPORTS HAVE CITED PULMONARY REACTIONS AS A CONTRIBUTING CAUSE OF DEATH. CHRONIC PULMONARY REACTIONS (DIFFUSE INTERSTITIAL PNEUMONITIS OR PULMONARY FIBROSIS, OR BOTH) CAN DEVELOP INSIDIOUSLY. THESE REACTIONS OCCUR RARELY AND GENERALLY IN PATIENTS RECEIVING THERAPY FOR SIX MONTHS OR LONGER. CLOSE MONITORING OF THE PULMONARY CONDITION OF PATIENTS RECEIVING LONG-TERM THERAPY IS WARRANTED AND REQUIRES THAT THE BENEFITS OF THERAPY BE WEIGHED AGAINST POTENTIAL RISKS. ( SEE RESPIRATORY REACTIONS.) Hepatotoxicity: Hepatic reactions, including hepatitis, cholestatic jaundice, chronic active hepatitis, and hepatic necrosis, occur rarely. Fatalities have been reported. The onset of chronic active hepatitis may be insidious, and patients should be monitored periodically for changes in biochemical tests that would indicate liver injury. If hepatitis occurs, the drug should be withdrawn immediately and appropriate measures should be taken. Neuropathy: Peripheral neuropathy, which may become severe or irreversible, has occurred. Fatalities have been reported. Conditions such as renal impairment (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine), anemia, diabetes mellitus, electrolyte imbalance, vitamin B deficiency, and debilitating disease may enhance the occurrence of peripheral neuropathy. Patients receiving long-term therapy should be monitored periodically for changes in renal function. Optic neuritis has been reported rarely in postmarketing experience with nitrofurantoin formulations. Hemolytic anemia: Cases of hemolytic anemia of the primaquine-sensitivity type have been induced by nitrofurantoin. Hemolysis appears to be linked to a glucose-6-phosphate dehydrogenase deficiency in the red blood cells of the affected patients. This deficiency is found in 10 percent of Blacks and a small percentage of ethnic groups of Mediterranean and Near-Eastern origin. Hemolysis is an indication for discontinuing nitrofurantoin capsules (monohydrate/macrocrystals); hemolysis ceases when the drug is withdrawn. Clostridium difficile -associated diarrhea: Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including nitrofurantoin, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile . C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents. If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile , and surgical evaluation should be instituted as clinically indicated.
Who should not take Macrobid
Anuria, oliguria, or significant impairment of renal function (creatinine clearance under 60 mL per minute or clinically significant elevated serum creatinine) are contraindications. Treatment of this type of patient carries an increased risk of toxicity because of impaired excretion of the drug. Because of the possibility of hemolytic anemia due to immature erythrocyte enzyme systems (glutathione instability), the drug is contraindicated in pregnant patients at term (38 to 42 weeks gestation), during labor and delivery, or when the onset of labor is imminent. For the same reason, the drug is contraindicated in neonates under one month of age. Nitrofurantoin capsules (monohydrate/macrocrystals) are contraindicated in patients with a previous history of cholestatic jaundice/hepatic dysfunction associated with nitrofurantoin. Nitrofurantoin capsules (monohydrate/macrocrystals) are also contraindicated in those patients with known hypersensitivity to nitrofurantoin.
Overdose — what happens if you take too much
Occasional incidents of acute overdosage of nitrofurantoin have not resulted in any specific symptoms other than vomiting. Induction of emesis is recommended. There is no specific antidote, but a high fluid intake should be maintained to promote urinary excretion of the drug. Nitrofurantoin is dialyzable.
U.S. Poison Control: call or text 1-800-222-1222 (free, 24/7). In an emergency call 911. From the FDA label; not medical advice.
Interactions
Antacids containing magnesium trisilicate, when administered concomitantly with nitrofurantoin, reduce both the rate and extent of absorption. The mechanism for this interaction probably is adsorption of nitrofurantoin onto the surface of magnesium trisilicate. Uricosuric drugs, such as probenecid and sulfinpyrazone, can inhibit renal tubular secretion of nitrofurantoin. The resulting increase in nitrofurantoin serum levels may increase toxicity, and the decreased urinary levels could lessen its efficacy as a urinary tract antibacterial.
How long does Nitrofurantoin and Nitrofurantoin, Macrocrystalline stay in your body?
The elimination half-life of nitrofurantoin and nitrofurantoin, macrocrystalline is about 20 minutes (roughly 0.3 hours) for the parent drug in adults with normal kidney function — the time it takes the body to clear about half of it. As a rule of thumb, a medicine is mostly gone after roughly 4 to 5 half-lives, though this varies from person to person with age and kidney or liver function. The FDA/DailyMed nitrofurantoin labels (Macrobid, Macrodantin, Furadantin) do not print an explicit numeric elimination half-life; the Macrodantin label states the drug is "readily absorbed and rapidly excreted in urine," with about 35-38% of a 100 mg dose recovered unchanged in urine over 24 hours and low blood levels at therapeutic doses. Published pharmacology puts the serum (plasma) half-life at about 20 minutes, so the parent drug clears from the blood within a few hours. Nitrofurantoin is not a prodrug and has no active metabolite that outlasts it. Because it is eliminated mainly by the kidneys, blood levels run higher and it clears more slowly when kidney function is reduced — it is contraindicated when creatinine clearance is under 60 mL/min, and older adults (who more often have reduced kidney function) need extra caution. It is dosed several times a day precisely because it leaves the bloodstream so quickly; this short blood half-life is not a drug-test detection window.
This is general information, not medical advice. It doesn’t tell you when a drug test would read negative (tests detect substances for different, often longer, windows) or when it’s safe to take another dose — ask your pharmacist or prescriber. Source: Macrodantin (nitrofurantoin macrocrystals) Capsules — FDA label, Clinical Pharmacology / Pharmacokinetics.
Dosage forms
Capsule
The forms currently marketed in the U.S., per the FDA National Drug Code Directory.
Ways to save
Ask for the generic
Same active ingredient, far cheaper. Is there a generic? →
Request a 90-day supply
Bulk fills usually lower the per-dose price vs monthly refills.
Use copay cards
Manufacturer copay cards & patient-assistance programs — especially for brand drugs.
Compare alternatives
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Frequently asked questions
- How much does Macrobid cost?
- Nobody can tell you what you will pay — your price is set by your insurer's formulary, your deductible and the pharmacy's markup, and none of those are published. What IS published is what the pharmacy paid to acquire it: about $2.14 per ml, per the CMS NADAC survey. Treat that as the floor, not the quote — ask the pharmacist for the cash price as well as your copay, because for cheap generics the cash price often wins.
- Is there a coupon or discount for Macrobid?
- pharmaranks is an independent ratings site, not a pharmacy — we don't issue coupons or sell Macrobid. To pay less, ask your prescriber or pharmacist whether a generic equivalent exists, check the manufacturer's copay/savings card and patient-assistance program, and compare a pharmacy discount card against your insurance copay. Prices vary by pharmacy, insurance, and location, so always confirm at the counter. This is general reference, not medical or financial advice.
- Who makes Macrobid?
- Macrobid is marketed by Almatica. You can see Almatica's full profile, rating, and other products on pharmaranks.
- Is Macrobid a brand-name or generic drug?
- Macrobid is a brand-name product with the active ingredient Nitrofurantoin and Nitrofurantoin, Macrocrystalline.
- Is Macrobid available over the counter?
- No. Macrobid is a prescription (Rx) medication in the US — you need a prescription from a licensed clinician (in person or via telehealth); it isn't sold over the counter. For some conditions there are OTC alternatives — ask your pharmacist.
- What forms does Macrobid come in?
- Macrobid is currently marketed as capsule, per the FDA's National Drug Code Directory.
- Is Macrobid FDA-registered?
- Macrobid is on record with the U.S. FDA under application number NDA020064. You can verify this on its official FDA label.
- Is Macrobid safe?
- There's no single safe-or-not verdict, and we don't yet have a composite recall-safety score for Macrobid. Review its FDA-label side effects and warnings below, and always consult a licensed professional.
- What are the side effects of Macrobid?
- Macrobid's side effects are taken directly from its FDA label. From the label: In clinical trials of nitrofurantoin capsules (monohydrate/macrocrystals), the most frequent clinical adverse events that were reported as possibly or probably drug-related were nausea (8%), headache (6%), and flatulence (1.5%).… Both common and serious reactions are documented in full on this page. This is general reference from the FDA, not medical advice — always consult a professional.
Clinical content sourced from the FDA label via openFDA (U.S. FDA). View the FDA label on DailyMed → Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.
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