Uses for fosfomycin

Fosfomycin is used to treat urinary tract infection and cystitis (bladder infection) in women. This medicine is an antibiotic. It works by killing bacteria or preventing their growth. However, this medicine will not work for colds, flu, or other virus infections.

This medicine is available only with your doctor's prescription.

Before using fosfomycin

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies have not been performed on the relationship of age to the effects of fosfomycin in children 12 years of age and below. Safety and efficacy have not been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of fosfomycin in the elderly. However, elderly patients are more likely to have age-related kidney, liver, or heart problems, which may require caution and an adjustment in the dose for patients receiving fosfomycin.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Cholera Vaccine, Live
• Methotrexate

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Diarrhea—Use with caution. May make this condition worse.

• Kidney disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

Proper use of fosfomycin

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so, may increase chance for side effects.

Only one dose of this medicine is needed to treat your UTI. The medicine will continue to fight the infection.

You may take this medicine with or without food.

The medicine is an orange-flavored powder that must be mixed with water before using. Never swallow the medicine in its dry form.

To use:

• Open the packet and pour all of the powder into 3 or 4 ounces (1/2 cup) of water. Do not use hot water.
• Stir until the powder is dissolved, and drink the mixture right away.

Drink extra fluids so you will pass more urine while you are using this medicine. This will keep your bladder working well and help prevent bladder problems.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage form (powder for solution):
  • For treatment of bladder infection:
    • Adults—3 grams (one packet) dissolved in water taken one time.
    • Teenagers 13 to 17 years of age—Dose must be determined by your doctor.
    • Children 12 years of age and below—Use and dose must be determined by your doctor.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions while using fosfomycin

If your symptoms do not improve within 2 or 3 days or if they become worse, check with your doctor.

This medicine may cause diarrhea, and in some cases it can be severe. It may occur 2 months or more after you stop taking this medicine. Do not take any medicine to treat diarrhea without first checking with your doctor. If you have any questions or if mild diarrhea continues or gets worse, check with your doctor.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects of fosfomycin

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Rare

• Blood in the urine
• burning while urinating
• cough or hoarseness
• difficult or painful urination
• fever or chills
• lower back or side pain
• painful or difficult urination

Incidence not known

• Abdominal or stomach pain or tenderness
• black, tarry stools
• bloating
• chest pain
• clay-colored stools
• constipation
• dark urine
• diarrhea
• difficulty with swallowing
• dizziness
• fast heartbeat
• headache
• hives
• itching
• large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
• light-colored stools
• loss of appetite
• nausea or vomiting
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• rash
• severe abdominal or stomach cramps and pain
• shortness of breath
• sores, ulcers, or white spots on the lips or in the mouth
• swollen or painful glands
• tightness in the chest
• unpleasant breath odor
• unusual bleeding or bruising
• unusual tiredness or weakness
• vomiting of blood
• watery and severe diarrhea, which may also be bloody
• wheezing
• worsening of asthma
• yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

• Itching of the vagina or genital area
• pain during sexual intercourse
• thick, white vaginal discharge with no odor or with a mild odor

Less common

• Acid or sour stomach
• back pain
• belching
• body aches or pain
• congestion
• dryness or soreness of the throat
• heartburn
• heavy bleeding
• indigestion
• lack or loss of strength
• pain
• painful menstruation
• runny or stuffy nose
• skin rash
• sneezing
• sore throat
• stomach discomfort or upset
• tender, swollen glands in the neck
• trouble with swallowing
• voice changes
• weakness

Rare

• Abnormal stools
• absent missed or irregular menstrual periods
• blindness
• blue-yellow color blindness
• blurred vision
• burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
• decreased vision
• difficulty with moving
• dry mouth
• excess air or gas in the stomach or intestines
• eye pain
• full feeling
• headache, severe and throbbing
• joint pain
• loss of appetite
• muscle aching or cramping
• muscle pains or stiffness
• nervousness
• passing gas
• sleepiness or unusual drowsiness
• sleeplessness
• stopping of menstrual bleeding
• swollen joints
• swollen, painful, or tender lymph glands in the neck, armpit, or groin
• trouble sleeping
• unable to sleep
• weight loss

Incidence not known

• Hearing loss

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Frequently asked questions

• What antibiotics are used to treat UTI?
• How long do antibiotics take to work?