Urifast (nitrofurantoin macrocrystals) is effective at treating or preventing bladder or urinary tract infections (UTIs) in both adults and children. Though an effective antibiotic, the medication's tendency to accumulate in the bladder makes it largely ineffective at treating or preventing infections elsewhere in the body.

Urifast will do nothing against viral or fungal infections. Though less common than bacteria, these infections do happen in the urinary tract and patients are advised to have the condition checked out by a doctor prior to starting treatment.

Likewise, some areas have developed bacterial resistance to Urifast, though this is not as broad a concern as with some other antibiotics. A doctor can also determine if the infection is resistant to Urifast, and recommend an alternative treatment if so.

Product Overview

Urifast comes in capsules, typically taken four times per day for infection and once per day for prevention.

Food or milk should be taken with each dose to improve absorption and reduce gastrointestinal side effects.

The medication is useful against a range of bacteria commonly associated with bladder infections or UTIs, including E. coli and several Staphylococcus and Streptococcus species. It is not effective against all types of bacteria, however; another good reason to have a doctor identify the specific bacteria.

Eradicating Infections

In treating infection, dosage depends on the severity of the infection and, to some extent, on patient weight.

Some improvement is usually noticed within a day or two of starting treatment, with significant alleviation of pain, discomfort, and other UTI symptoms. Treatment usually lasts around one week.

In otherwise healthy adults treatment is typically:

• 50 to 100 mg should be taken four times per day, spaced apart as evenly as possible.
• Food or milk should be consumed with each dose to aid with absorption.
• Treatment should continue for at least one week.
• Treatment should continue for three days after the infection has cleared up.

In pediatric patients dosage depends on weight; as a general rule, 5 mg of Urifast per kg of weight per day. The total dose should be divided into four smaller doses, taken at evenly-spaced intervals throughout the day.

If there is little or no improvement after a week of taking Urifast a doctor should be consulted; it may not be a bacterial infection, or the bacteria may have developed resistance.

Preventing Infection

Individuals who are at risk of acquiring a UTI, or who are simply prone to recurring infections, use Urifast to prevent an infection from taking hold.

As a preventive measure treatment is simpler:

• Adults should take 50 to 100 mg once per day, typically at bedtime.
• Children should be given 1 mg per kg of weight per day, at bedtime.
• Treatment may continue for as long as necessary, but there are risks associated with long-term use.

Again each dose should be taken with food or milk. A doctor can help determine duration.

Adverse Effects

In most cases side effects are similar to those experienced with any antibiotic, including:

• Abdominal discomfort
• Nausea
• Vomiting
• Appetite loss
• Headache
• Diarrhea

The above symptoms are not cause for concern unless severe, and will stop when treatment ends.

Urifast sometimes causes the urine to be brown. This is normal and not cause for concern.

As a preventive treatment, duration can last considerably longer than the usual week. There is a slight risk---1 in 5000 patients---that serious pulmonary (lung) complications may develop with long-term use. The risk is a little higher for women and elderly patients. Pulmonary complications can sometimes be resolved if caught early, but sometimes are permanent.

All patients taking Urifast for more than a couple of weeks should be alert for any change in lung function, including:

• Frequent coughing
• Chest pain
• Difficulty breathing
• Any other change in breathing/lung function

Regular doctor checkups will also help monitor for developing complications.

Other medications can interact with Urifast; of particular concern are:

• Probenecid
• Sulfinpyrazone
• Antacids containing magnesium trisilicate

It's best to always double-check with a doctor or pharmacist before mixing other treatments with Urifast, including seemingly-innocuous over-the-counter medications, supplements, and vitamins.