Rx required in the US, UK, and Canada

Nitrofurantoin

Also called Macrobid, Macrodantin, Furadantin. Urinary antibacterial.

Uncomplicated bladder infection in the right adult. It does not reliably treat a kidney infection.

Last reviewed 2 November 2026. RxNorm 7454. SNOMED CT substance 373543005.

What nitrofurantoin treats

Primary uses clinicians actually reach for this drug for. Local resistance and your own history can take a use off the list.

Uncomplicated cystitis in non-pregnant women, when the story is burning, urgency, or frequency without fever, flank pain, or vomiting.
The usual Macrobid-type course clinicians write for that picture is 100 mg every 12 hours for 5 days.

Long-term suppression is a specialist plan because months of nitrofurantoin can injure the lungs, liver, and nerves. A 5-day course is a different exposure. New cough, shortness of breath, numbness, or yellow skin still deserves a call.

What it does not treat

Kidney infection
Fever, back pain, or vomiting with urinary symptoms
Urinary symptoms in men, in pregnancy, or with a catheter, as a casual telehealth default
Sinusitis, bronchitis, skin infections, and colds
Sexually transmitted infections. Burning can be an STI.

Forms, dosing examples, and how to take it

Forms

Macrobid and generics: nitrofurantoin monohydrate/macrocrystals, typically 100 mg, taken twice daily
Macrodantin and generics: macrocrystals, often taken four times daily
Furadantin suspension, a different product
These are not interchangeable by splitting tablets or changing the clock.

Adult examples

The 5-day twice-daily plan is the common published regimen for uncomplicated cystitis with the monohydrate/macrocrystal product. It is the regimen a prescriber writes after deciding you have that infection. It is not a kidney-infection plan and not a plan for every person with burning.

Educational examples only. Not a dosing instruction for a named patient.
Situation	Example adults may see on a label or guideline	Limit
Uncomplicated cystitis, monohydrate/macrocrystals (Macrobid type)	100 mg every 12 hours for 5 days	Take it with food. This is the pattern to expect if this product is chosen.
Macrocrystal product (Macrodantin type)	Often 50 to 100 mg four times daily for a short course	Do not stretch a twice-daily Macrobid prescription into this schedule or the reverse.
Kidney infection or any systemic symptoms	Not nitrofurantoin	Go to in-person care. This drug does not reach kidney tissue reliably.

Food, minerals, and administration

Take it with food to improve absorption and cut nausea.
Urine often turns dark yellow or brown. That color is expected.
Magnesium antacids can reduce absorption. Separate them if the label says so.
The prescriber checks kidney function. Significantly reduced function is a reason to choose a different drug, because the medicine may never reach the urine and side effects rise.

Can an online doctor prescribe nitrofurantoin?

Yes only inside the narrow band below. The same visit is supposed to refuse the drug outside that band.

When a prescription is plausible

Yes for many non-pregnant adult women with typical bladder symptoms and none of the red flags. This is one of the infections telehealth most often treats.
The clinician can still decline, ask for a urine test, or send you to urgent care.

What the visit should cover

Fever, flank or back pain, vomiting, and ability to keep fluids down.
Pregnancy, sex, catheter use, kidney disease, and transplant history.
Discharge, pelvic pain, or a new partner, because an STI can look like a UTI.
Prior nitrofurantoin lung or liver problems, and G6PD deficiency.

When the clinician should refuse

Fever, one-sided back pain, shaking chills, or vomiting.
Pregnancy, especially near term. Male patients and catheter users usually need a different evaluation.
Symptoms that sound like an STI rather than cystitis.
A request to mail a bottle while symptoms have already become systemic.

How same-day e-prescriptions and local pickup work. If the drug is prescribed, use a pharmacy you can reach today. Mail order is the wrong speed for an acute infection.

Side effects, allergies, pregnancy, and alcohol

Often mild

Nausea
Headache
Gas
Brown or dark yellow urine
Decreased appetite

Get care

New cough or shortness of breath
Numbness
Yellow skin or dark urine beyond the expected brown color, with illness
Severe diarrhea
Wheezing, rash, or swelling
Fever that starts after the urinary symptoms

Allergies and cross-reaction

A nitrofurantoin allergy means this drug and usually the whole family of nitrofuran urinary drugs. It does not say anything about penicillin. Do not replace it with ciprofloxacin on your own.

Pregnancy

Nitrofurantoin is avoided at the very end of pregnancy because of hemolytic anemia in the newborn. Earlier in pregnancy it is sometimes used for UTI when a clinician chooses it. Obstetric care should make that call, not a message visit built for non-pregnant patients.

Alcohol

No disulfiram-style warning. Alcohol worsens nausea and dehydration, which is already the main tolerability problem with this drug. Skip it during a short UTI course.

Severe watery diarrhea during or after any antibiotic can be C. difficile. Mouth or throat swelling is an emergency: call 911 or 999.

Generic, coupon, and telehealth pickup

These are budgeting bands for a common U.S. generic fill, not a national average and not a GoodRx quote. Discount-card prices change by pharmacy and ZIP code, and a card usually cannot be combined with insurance on the same fill. A telehealth visit is a separate bill, often advertised around $29 to $129 in late October 2026. The medicine is extra. Ask the pharmacy for today’s cash price and today’s coupon price before you travel.

Average-style planning bands for budgeting. Confirm the live cash price and the live coupon.
Product	U.S. cash planning band	Discount-card band, GoodRx-type	Telehealth plus local pickup
Generic nitrofurantoin monohydrate/macrocrystals 100 mg, 10 capsules	Often about $20–$70	Often about $15–$40	Visit fee plus local pickup. Ten capsules is a common 5-day twice-daily count.
Brand Macrobid	Often well above the generic	Ask for generic unless the prescription forbids it	Macrodantin is not a cheaper way to fill a Macrobid prescription.

Questions about nitrofurantoin

Can I get Macrobid online for a UTI?

Often, if you are a non-pregnant adult woman with typical bladder symptoms and no fever, back pain, or vomiting. The clinician must be licensed where you are. Pickup should be local the same day if the drug is in stock. Men, pregnant patients, and anyone with fever need in-person care.

Why won’t nitrofurantoin treat a kidney infection?

It concentrates in the urine and does not reliably reach kidney tissue. Fever, flank pain, or vomiting can be a kidney infection. Using Macrobid there delays an effective drug.

What is the difference between Macrobid and Macrodantin?

Both are nitrofurantoin. Macrobid is the twice-daily monohydrate/macrocrystal product commonly used for a 5-day cystitis course. Macrodantin is usually taken four times a day. The pharmacy cannot freely swap them to match a coupon.

Why is my urine brown?

Nitrofurantoin commonly turns urine dark yellow or brown. That alone is expected. Pain, fever, or yellow skin is not. Call for those.

What should I do if I miss a dose?

Take a missed dose when you remember unless it is close to the next dose. Skip it then. Do not take two doses at once. If you vomit soon after a dose, ask the pharmacist before you repeat it. The label and the pharmacist outrank this sentence.

Labels: DailyMed. Stewardship: CDC. Pharmacy checks: FDA BeSafeRx. Codes were read from RxNav on 2 November 2026 for ingredient RxCUI 7454.