Can Macrobid Capsules Be Opened

In our latest question and answer, the pharmacist discusses why Macrobid capsules should not be opened.

Question

I was diagnosed with a UTI and prescribed Macrobid (nitrofurantoin). Can I open the capsules?

Asked by Ashley On Jul 21, 2018

Answered by
Medical Content Reviewed By PharmacistAnswers Staff

On Jul 21, 2018

Although Macrobid (nitrofurantoin monohydrate; nitrofurantoin macrocrystals) capsules contain a dry powder and is not technically an extended release product (more on this below), they are not recommended to be opened. They should be swallowed whole. This is for a few reasons:

  • Nitrofurantoin has been reported to cause esophageal irritation when applied directly to mucus membranes in the mouth and throat. The capsule protects the powder from coming into contact with these areas, and improves tolerability.

  • Macrobid capsules actually contain two forms of nitrofurantoin, "monohydrate" and "macrocrystals". The macrocrystalline form is more slowly absorbed due to a slower rate of dissolution. This form can produce fewer adverse gastrointestinal effects. However, if it comes into contact with saliva/gastic juices early, it may dissolve faster, causing more side effects.

  • Macrobid, in a technical sense, is not an extended release product as the capsule itself does not have extended release properties. However, when exposed to gastric and intestinal fluids, the nitrofurantoin monohydrate component of Macrobid forms a gel matrix and releases nitrofurantoin over time. This is why it is able to be dosed only twice a day, when compared to other nitrofurantoin products (e.g. Macrodantin), which need to be dosed four times a day. Opening Macrobid capsules and taking the powder can cause the gel matrix to form to early, creating a choking hazard and potentially altering the extended release properties.


If you are unable to take the capsule form, it is available in a liquid suspension dosage form in a strength of 25mg/mL. Ask your doctor if they are able to prescribe that for you instead. It is specifically formulated not cause the mouth/throat irritation the powder form can cause.

About the Pharmacist

Dr. Brian Staiger Pharm.D

Dr. Brian Staiger is a licensed pharmacist in New York State and the founder of PharmacistAnswers.com. He graduated from the University At Buffalo with a Doctor of Pharmacy degree in 2010. He has been featured in numerous publications including the Huffington Post as well as a variety of health and pharmacy-related blogs. Please feel free to reach out to him directly if you have any inquiries or want to connect! He's answered thousands of medication and pharmacy-related questions and he's ready to answer yours! Brian.Staiger@PharmacistAnswers.com Office: 716-389-3076

About Nitrofurantoin

Nitrofurantoin is an antibacterial agent and is specifically used to treat urinary tract infections caused by both gram-negative and gram-positive bacteria. It is available in two forms, Macrobid (nitrofurantoin monohydrate plus nitrofurantoin macrocrystals) and Macrodantin (nitrofurantoin macrocrystals). The key difference is that Macrobid is dosed twice daily while Macrodantin is dosed four times daily. Both may be given with or without food, but administration with food, water, or milk may enhance tolerance. A key side effect to be aware about is that nitrofurantoin cause discolor urine. This effect will go away however after the medication has been discontinued.

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