Fosfomycin

Uses

What is Fosfomycin used for?

Fosfomycin is commonly used to treat bladder infections (such as acute cystitis or lower urinary tract infections) in women. It works by stopping the growth of bacteria. This antibiotic treats only bacterial infections. It will not work for viral infections (such as common cold, flu). Using any antibiotic when it is not needed can cause it to not work for future infections.

Fosfomycin should not be used to treat infections outside the bladder (such as kidney infections).

How should I take Fosfomycin?

Take this medication by mouth as directed by your doctor, usually 1 packet (sachet) as a single dose. Mix this drug with water before taking it. Pour the contents of 1 packet (sachet) into a half glass (4 ounces or 120 milliliters) of cold water and stir to dissolve. Do not use warm or hot water. Drink all of the mixture right away.

Your symptoms should get better within 2 to 3 days. Tell your doctor if you do not get better after 3 days or if you get worse.

How do I store Fosfomycin?

Fosfomycin is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Fosfomycin in the bathroom or the freezer. There may be different brands of Fosfomycin that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Fosfomycin down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Fosfomycin?

Before taking fosfomycin, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease.

If you develop symptoms of a kidney infection (such as pain in your side or lower back area, fever, chills), contact your doctor right away. Your doctor may change your treatment.

This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.

This product may contain sugar and/or aspartame. Caution is advised if you have diabetes, phenylketonuria (PKU), or any other condition that requires you to limit/avoid these substances in your diet. Ask your doctor or pharmacist about using this product safely.

Fosfomycin may cause live bacterial vaccines (such as typhoid vaccine) to not work as well. Do not have any immunizations/vaccinations while using this medication unless your doctor tells you to.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

This drug passes into breast milk in small amounts, but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.

Is it safe during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this Fosfomycin during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking Fosfomycin. Fosfomycin is pregnancy risk category B according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

• A=No risk,
• B=No risk in some studies,
• C=There may be some risk,
• D=Positive evidence of risk,
• X=Contraindicated,
• N=Unknown

Side effects

What side effects can occur from Fosfomycin?

Diarrhea, nausea, headache, vaginal discomfort, or dizziness may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: vision changes, unusual weakness.

This medication may rarely cause a severe intestinal condition (Clostridium difficile-associated diarrhea) due to a type of resistant bacteria. This condition may occur during treatment or weeks to months after treatment has stopped. Tell your doctor right away if you develop: diarrhea that doesn’t stop, abdominal or stomach pain/cramping, blood/mucus in your stool.

Do not use anti-diarrhea products or narcotic pain medications if you have any of these symptoms because these products may make them worse.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Interactions

What drugs may interact with Fosfomycin?

Some products that may interact with this drug include: metoclopramide, probenecid.

Although most antibiotics are unlikely to affect hormonal birth control such as pills, patch, or ring, a few antibiotics (such as rifampin, rifabutin) can decrease their effectiveness. This could result in pregnancy. If you use hormonal birth control, ask your doctor or pharmacist for more details.

Fosfomycin may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with Fosfomycin?

Fosfomycin may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Fosfomycin?

Fosfomycin may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.

Dosage

The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Fosfomycin.

What is the dose of Fosfomycin for an adult?

Usual Adult Dose for Cystitis

3 g (1 sachet) orally once as a single dose

Comments:

-This drug should not be used for the treatment of pyelonephritis or perinephric abscess.

Use: For the treatment of uncomplicated urinary tract infections (acute cystitis) in women due to susceptible strains of Escherichia coli and Enterococcus faecalis

Usual Adult Dose for Transurethral Prostatectomy

3 g (1 sachet) orally on the evening before the procedure and then 3 g orally on the evening after the procedure

Comments:

-Not approved by US FDA.

Other Comments

Administration advice:

-May take with or without food

-Do not take this drug in its dry form; always mix with water prior to ingestion; take immediately after dissolving in water.

Reconstitution/preparation techniques:

-The contents of 1 sachet should be dissolved in 3 to 4 ounces of water (1/2 cup) immediately prior to administration; hot water should not be used.

General:

-Urine specimens for culture and susceptibility testing should be obtained before and after oral therapy.

-If bacteriuria persists or reappears after use of this drug, alternative therapeutic regimens should be selected based on microbiological studies.

Patient advice:

-If symptoms do not improve in 2 to 3 days after taking the single oral dose, contact healthcare provider promptly.

What is the dose of Fosfomycin for a child?

Precautions

Safety and efficacy have not been established in patients younger than 12 years; only approved for use in women 18 years or older.

How is Fosfomycin available?

Fosfomycin is available in the following dosage forms and strengths:

• Oral powder for reconstitution

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Fosfomycin, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.