Fosfomycin
Also known as: Monurol
> **Important:** This medication is typically reserved for highly resistant infections where other antibiotics have failed. Follow your veterinarian's instructions exactly. - **Administration:** If provided as human granules (packets), dissolve the entire contents of a single-dose sachet in 1/2 cup (90-120 mL) of cool or room-temperature water immediately before giving it to your pet. **Do not use hot water.** - **Food:** Can be given with or without food. If it causes stomach upset, giving it with a small treat or meal may help. - **Side Effects:** The most common side effect is diarrhea. Contact your veterinarian if your pet develops severe or bloody diarrhea, vomiting, or loss of appetite. - **Toxicity Warning:** This drug can be highly toxic to the kidneys in **cats**. If your cat was prescribed this medication under special circumstances, monitor them extremely closely for changes in thirst, urination, or lethargy, and attend all scheduled blood test appointments.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Susceptible infections (Investigational)
- Urinary Tract Infection (MDR E. coli)
How it is given
Possible side effects
- Diarrhea (most common in humans)
- Gastrointestinal upset
- Renal tubular damage / Nephrotoxicity (observed in cats)
Cautions & contraindications
- Young cats (Contraindicated due to nephrotoxicity)
- Adult cats (Relative contraindication; use with extreme caution if at all)
- > **Warning:** Appears to be highly nephrotoxic in cats, causing tubular necrosis and significant increases in serum creatinine. Use is generally contraindicated in felines. - **Renal Impairment:** In humans, renal dysfunction can substantially increase the drug's half-life and reduce urine levels. - **Dosing Strategy:** In humans, this drug is used as a one-time dose; multiple doses do not enhance efficacy and increase the incidence of adverse events. Veterinary protocols are still investigational.
Drug interactions
- Metoclopramide: Can decrease serum concentrations and reduce urine levels of fosfomycin.
- Prokinetic agents (bethanechol, cisapride, domperidone, ranitidine, laxatives): Theoretical risk of decreasing serum and urine concentrations by increasing GI motility, similar to metoclopramide.
Frequently asked questions
What is Fosfomycin used for in pets?
> **Important:** This medication is typically reserved for highly resistant infections where other antibiotics have failed. Follow your veterinarian's instructions exactly. - **Administration:** If provided as human granules (packets), dissolve the entire contents of a single-dose sachet in 1/2 cup (90-120 mL) of cool or room-temperature water immediately before giving it to your pet. **Do not use hot water.** - **Food:** Can be given with or without food. If it causes stomach upset, giving it with a small treat or meal may help. - **Side Effects:** The most common side effect is diarrhea. Contact your veterinarian if your pet develops severe or bloody diarrhea, vomiting, or loss of appetite. - **Toxicity Warning:** This drug can be highly toxic to the kidneys in **cats**. If your cat was prescribed this medication under special circumstances, monitor them extremely closely for changes in thirst, urination, or lethargy, and attend all scheduled blood test appointments.
Is Fosfomycin safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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