Fosfomycin Side Effects

Medically reviewed by Drugs.com. Last updated on Jun 1, 2024.

Applies to fosfomycin: oral powder for solution.

Precautions

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 fosfomycin. 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.

Common side effects of fosfomycin

Some side effects of fosfomycin 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:

Serious side effects of fosfomycin

Along with its needed effects, fosfomycin 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 while taking fosfomycin:

For healthcare professionals

Applies to fosfomycin: oral granule for reconstitution, oral powder for reconstitution.

Gastrointestinal adverse events

• Very common (10% or more): Diarrhea (up to 10.4%)
• Common (1% to 10%): Nausea, abdominal pain, dyspepsia, retching, stomach ache
• Uncommon (0.1% to 1%): Abnormal stools, constipation, dry mouth, flatulence, vomiting
• Frequency not reported: Pseudomembranous colitis
• Postmarketing reports: Toxic megacolon, antibiotic-associated colitis, oral paresthesias (temporary tingling of mouth, tongue, cheek)^[Ref]

Nervous system

• Very common (10% or more): Headache (up to 10.3%)
• Common (1% to 10%): Dizziness
• Uncommon (0.1% to 1%): Dysgeusia, paresthesia, migraine, somnolence, vertigo
• Postmarketing reports: Hearing loss, temporary alterations of taste (dysgeusia, hypogeusia)^[Ref]

Genitourinary

• Common (1% to 10%): Vaginitis, dysmenorrhea, vulvovaginitis
• Uncommon (0.1% to 1%): Hematuria, dysuria, menstrual disorder^[Ref]

Other

• Common (1% to 10%): Pain, asthenia, injection site phlebitis
• Uncommon (0.1% to 1%): Fatigue, infection, ear disorder, fever, influenza syndrome
• Frequency not reported: Facial edema^[Ref]

Hypersensitivity

• Very rare (less than 0.01%): Anaphylactic shock
• Postmarketing reports: Anaphylaxis, anaphylactic reactions (including anaphylactic shock), hypersensitivity^[Ref]

Respiratory

• Common (1% to 10%): Rhinitis, pharyngitis
• Uncommon (0.1% to 1%): Dyspnea
• Frequency not reported: Asthmatic attack
• Postmarketing reports: Asthma, exacerbation of asthma^[Ref]

Dermatologic

• Common (1% to 10%): Rash
• Uncommon (0.1% to 1%): Pruritus, skin disorder, urticaria
• Frequency not reported: Angioedema^[Ref]

Angioedema has also been reported during postmarketing experience.^[Ref]

Musculoskeletal

• Common (1% to 10%): Back pain
• Uncommon (0.1% to 1%): Myalgia^[Ref]

Metabolic

• Uncommon (0.1% to 1%): Anorexia, decreased appetite, hypernatremia and/or hypokalemia, increased alkaline phosphatase^[Ref]

Increased alkaline phosphatase was generally transient and not clinically significant.^[Ref]

Hematologic

• Uncommon (0.1% to 1%): Lymphadenopathy
• Rare (0.01% to 0.1%): Aplastic anemia, eosinophilia
• Frequency not reported: Agranulocytosis, granulocytopenia, leukopenia, pancytopenia, thrombocytopenia, increased eosinophil count, increased or decreased white blood cell count, increased and decreased platelet count, decreased hematocrit, decreased hemoglobin^[Ref]

Increased eosinophil count, increased or decreased white blood cell count, increased and decreased platelet count, decreased hematocrit, and decreased hemoglobin were generally transient and not clinically significant.

Aplastic anemia has also been reported during postmarketing experience.^[Ref]

Hepatic

• Uncommon (0.1% to 1%): Increased ALT, increased AST
• Very rare (less than 0.01%): Fatty liver
• Frequency not reported: Increased bilirubin, hepatitis, cholestatic hepatitis, icterus
• Postmarketing reports: Cholestatic jaundice, hepatic necrosis^[Ref]

Fatty liver was completely reversible after IV fosfomycin was discontinued.

Increased bilirubin, increased ALT, and increased AST were generally transient and not clinically significant.^[Ref]

Cardiovascular

• Uncommon (0.1% to 1%): Tachycardia
• Postmarketing reports: Hypotension^[Ref]

Psychiatric

• Uncommon (0.1% to 1%): Insomnia, nervousness
• Frequency not reported: Confusion^[Ref]

Ocular

• Very rare (less than 0.01%): Visual impairment
• Frequency not reported: Unilateral optic neuritis^[Ref]

See also:

Frequently asked questions

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

Further information

Fosfomycin side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer