fosfomycin

REMS

Uncomplicated urinary tract infections in women (acute cystitis).

Action ⬆ ⬇

Inactivates an enzyme crucial for bacterial cell wall synthesis.
Decreases adherence of bacteria to uroepithelial cells.

Therapeutic effects:

Bactericidal action against susceptible bacteria.

Spectrum:

Active against: Enterococcus faecalis and Escherichia coli.

Pharmacokinetics ⬆ ⬇

Absorption: Rapidly absorbed and converted to fosfomycin, its active component, resulting in 37% bioavailability.

Distribution: Distributes to kidneys and bladder wall; crosses the placenta.

Metabolism/Excretion: Excreted unchanged in urine (38%) and feces (18%).

Half-Life: 5.7 hr.

Time/Action Profile ⬆ ⬇

(bactericidal urine levels‡)

ROUTE	ONSET	PEAK	DURATION
PO	rapid	2–4 hr	unknown

‡Symptoms may take 24–48 hr to subside.

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Pyelonephritis;
Lactation: Lactation.

Use Cautiously in:

OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
Pedi: Children 12 yr (safety and effectiveness not established).

Adv. Reactions/Side Effects ⬆ ⬇

GI: dyspepsia, CLOSTRIDIOIDES DIFFICILE-ASSOCIATED DIARRHEA (CDAD), diarrhea, nausea

GU: vaginitis

Neuro: dizziness, headache, weakness

Interactions ⬆ ⬇

Drug-drug:

Urinary excretion and blood levels are ↓ by metoclopramide.

Route/Dosage ⬆ ⬇

PO (Adults ): 3-g single dose.

Availability ⬆ ⬇

(Generic available)

Granules for oral solution: 3 g/sachet

Assessment ⬆ ⬇

Assess patient for signs and symptoms of cystitis (frequency, urgency, painful urination).
Obtain urine specimen for culture and sensitivity before administration.
Monitor bowel function. Diarrhea, abdominal cramping, fever, and bloody stools should be reported to health care professional promptly as a sign of
Clostridioides difficile
-associated diarrhea (CDAD). May begin up to several wk following cessation of therapy.

Implementation ⬆ ⬇

PO: Do not take medication in dry form. Pour entire contents of single sachet into 3–4 oz (½ cup) water and stir to dissolve. Do not use hot water. Drink immediately after mixing. May be administered with or without food.

Patient/Family Teaching ⬆ ⬇

Instruct patient on correct preparation of sachet.
Instruct patient to notify health care professional immediately if diarrhea, abdominal cramping, fever, or bloody stools occur and not to treat with antidiarrheals without consulting health care professionals.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected and to avoid breastfeeding during therapy.
Advise patient to notify health care professional if symptoms have not improved or persist more than 2–3 days after treatment.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇