What is Nitrofurantoin Mono/Macro: Uses, Warnings & Interactions

Medically reviewed by Gerardo SisonPharm.D.
Licensed Pharmacist
Updated May 14, 2025  •  Published Dec 30, 2020
Datos Verificados

Nitrofurantoin monohydrate/macrocrystals, often sold under the brand names Macrobid and Macrodantin, is a type of antibiotic of the nitrofuran drug class. It works by killing the bacteria or slowing down their growth in the urinary tract. Nitrofurantoin mono/macro is effective because it stops bacteria from making important proteins they need to multiply and spread. It’s particularly useful for treating the specific bacteria that cause urinary tract infections (UTIs).

Nitrofurantoin Mono/Macro overview

BRAND NAMES:

  • Macrobid, Macrodantin, Furadantin, Aratoin

Generic Names:

  • Nitrofurantoin monohydrate/macrocrystals

Uses:

  • Acute, uncomplicated bacterial UTIs

Therapeutic Classes:

  • Antibiotic

  • Nitrofuran

Forms:

  • Capsule

How it’s taken:

  • By mouth

What is Nitrofurantoin Mono/Macro used for?

Nitrofurantoin mono/macro is used to treat UTIs, which are commonly caused by bacteria entering the urethra and multiplying in the bladder. The medication comes into play by killing the bacteria or obstructing their ability to multiply and spread, ultimately helping to clear the infection. Nitrofurantoin mono/macro is not appropriate for treating all types of bladder infections, especially if they are caused by bacteria that do not respond to this particular antibiotic. It should not be used for infections caused by viruses, fungi, or parasites.

Key takeaways

  • Take this medication with food or milk to avoid stomach upset and improve absorption. If you experience persistent nausea or vomiting, contact your doctor or healthcare provider for medical advice.

  • Complete the full course of treatment, even if you feel better, to prevent the infection from returning. Stopping the medication too early may lead to antibiotic resistance.

  • Stay well-hydrated by drinking plenty of water during treatment to help prevent kidney or bladder problems. Aim for at least six to eight glasses of water per day unless instructed otherwise by your healthcare provider.

  • If you experience symptoms like fever, chills, or back pain, contact your healthcare provider, as these may indicate a more serious infection. Seek immediate medical attention if you have difficulty breathing or swelling of the face, lips, or tongue.

  • Avoid taking antacids containing magnesium trisilicate within two hours of taking Nitrofurantoin mono/macro as they can reduce its effectiveness. If you need to take an antacid, choose one without magnesium trisilicate or consult your pharmacist for advice.

What form(s) does Nitrofurantoin Mono/Macro come in

  • Oral capsule

    • 100 mg

What are common Nitrofurantoin Mono/Macro doses?

  • Oral capsule

    • 100 mg

Common Nitrofurantoin Mono/Macro prescriptions

  • Nitrofurantoin Monohyd Macro
    100mg capsule

How to take Nitrofurantoin Mono/Macro

  • Take all of the medicine in your prescription to clear up your infection, even if you feel better after the first few doses.

  • It is best to take this medicine with food or milk.

  • Your healthcare provider will provide directions on how much to take at a given time. Do not use more than directed.

What to do if you miss a dose of Nitrofurantoin Mono/Macro

  • If you realize you’ve missed a dose, you should take it immediately upon remembering.

  • If the time for the next dose is near, skip the missed dose. It's crucial not to take two doses close together.

  • Doubling doses can increase the risk of side effects. If a dose is missed, don’t try to compensate by taking extra medication.

  • Keeping to a regular dosing schedule helps avoid missed doses. Try taking the medication at the same times each day.

  • If you frequently miss doses, talking to a healthcare provider can help. They may offer strategies to remember or adjust the dosing schedule.

Nitrofurantoin Mono/Macro contraindications

You should not take this medication if any of the following apply to you:

  • A history of hypersensitivity or an allergic reaction to Nitrofurantoin mono/macro or any ingredients of the medication

  • Pregnant in the last weeks of gestation (week 38 or later), labor, and delivery

  • Severe kidney problems, such as kidney disease or kidney failure

  • An inability to urinate or a decreased amount of urine

  • A history of liver disease or other liver problems with nitrofurantoin

  • Neonates under one month of age

Nitrofurantoin Mono/Macro warnings

  • Nitrofurantoin mono/macro can cause serious lung problems that may happen suddenly or develop slowly over time. In rare cases, these problems have been fatal. If you experience a cough, shortness of breath, chest pain, or fever, stop taking the medication and immediately contact your doctor. 

  • Although rare, Nitrofurantoin mono/macro may cause liver damage, including hepatitis or liver failure, which can be serious or even fatal. Symptoms may include yellowing of the skin or eyes, dark urine, or unusual tiredness. Your doctor may check your liver function during treatment, especially if you’re on the medication for a long time.

  • This medicine can cause nerve damage, especially if you have kidney problems, diabetes, anemia, or vitamin B deficiency. Nerve damage can feel like tingling, numbness, or burning in your hands or feet. In some cases, the nerve issues may not go away. Let your doctor know if you notice these symptoms.

  • Nitrofurantoin mono/macro may cause a type of anemia that happens when red blood cells break down too quickly, especially in people with a condition called G6PD deficiency. This is more common in certain ethnic groups. If this occurs, the medicine should be stopped immediately.

  • As with many antibiotics, Nitrofurantoin mono/macro can sometimes cause a serious gut infection called Clostridium difficile (C. diff), which may lead to watery or bloody diarrhea. This can happen even weeks after finishing the medication. Let your doctor know if this happens.

  • Nitrofurantoin mono/macro may interfere with certain urine tests for sugar, so let your doctor know you’re taking it if you're being tested. 

Nitrofurantoin Mono/Macro interactions

  • Make sure your doctor knows if you are also using probenecid or sulfinpyrazone. These medications can raise nitrofurantoin levels in the blood and increase the risk of side effects.

  • You may need to avoid taking certain antacids containing magnesium trisilicate while using nitrofurantoin, as they can affect the absorption of nitrofurantoin and make the medicine less effective.

Nitrofurantoin Mono/Macro side effects

Nitrofurantoin monohydrate/macrocrystals may cause various side effects. The severity and frequency of side effects can vary. While some people experience side effects, others may not notice any at all.

Serious side effects

  • Serious nausea, vomiting, loss of appetite, or pain in your upper stomach

  • Yellowing of your skin or the whites of your eyes

  • Numbness, tingling, or burning pain in your hands, arms, legs, or feet

  • Blisters, peeling, or red skin rash

  • Blurred vision

  • Cough, fever, chills, weakness, shortness of breath, or chest pain

  • Persistent diarrhea or loose, watery stools that may contain blood

  • Allergic reactions, with symptoms such as itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, and trouble breathing

Less serious side effects

  • Headache

  • Dizziness

  • Hair loss

  • Dark-colored urine

  • Mild nausea, vomiting, constipation, stomach upset, or pain

Pay attention to how your body reacts to the medication. Some side effects might get better as your body gets used to it. However, if you notice serious side effects, you should get medical help right away. Look out for symptoms like chest pain, trouble breathing, or severe allergic reactions, such as hives, rash, or swelling in your throat.

Sources:

Medically reviewed by Gerardo SisonPharm.D.
Licensed Pharmacist

Gerardo Sison, Pharm.D., graduated from the University of Florida. He has worked in both community and hospital settings, providing drug information and medication therapy management services. As a medical writer, he hopes to educate and empower patients to better manage their health and navigate their treatment plans.

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