Fosfomycin

Listed in Dosage.

Adult : PO Acute uncomplicated UTI As fosfomycin tromethamine: 3 g as a single dose. IV Severe infections As fosfomycin disodium: Up to 20 g/day.

Intravenous
Severe infections

Oral
Acute uncomplicated urinary tract infections

Acute uncomplicated urinary tract infections: No dosage adjustment needed.
Severe infections: Dosage adjustment needed.

Should be taken on an empty stomach. Take 1 hr before or 2 hr after meals.

Oral powd: Dissolve the contents of a single-dose sachet containing 3 g of the drug in 90-120 mL of water. Do not use hot water. Powd for infusion: Dissolve 2 g and 8 g in 50 mL and 200 mL, respectively, using water for inj or glucose 5% or 10%.

Hypersensitivity to fosfomycin.

Patient w/ cardiac insufficiency, HTN, hyperaldosteronism, hypernatraemia or pulmonary oedema. Renal impairment (IV). Pregnancy and lactation.

GI disturbances (e.g. nausea, diarrhoea), transient increase in aminotransferase levels, headache, visual disturbances, skin rashes, eosinophilia, angioedema, aplastic anaemia, exacerbation of asthma, cholestatic jaundice, hepatic necrosis, toxic megacolon.
Potentially Fatal: Anaphylactic shock, antibiotic-associated colitis and pseudomembranous colitis.

PO: B

Certain adverse effects may occur which may impair ability to drive or operate machinery.

Monitor serum electrolyte levels and water balance; signs and symptoms of UTI.

Symptoms: Vestibular loss, impaired hearing, metallic taste, and general decline in taste perception. Management: Symptomatic and supportive treatment.

Additive or synergistic effect w/ β-lactam antibiotics (e.g. penicillin, ampicillin, cefazolin, carbapenems) and anti-staphylococcal agents (e.g. linezolid, quinupristin/dalfopristin, moxifloxacin). Reduced serum levels w/ drugs which increase GI motility (e.g. metoclopramide).

Description: Fosfomycin exerts bactericidal effect on proliferating pathogens by preventing the enzymatic synthesis of the bacterial cell wall. It inhibits the 1st stage of intracellular bacterial cell wall synthesis by blocking peptidoglycan synthesis.
Pharmacokinetics:
Absorption: Rapidly absorbed from the GI tract (fosfomycin tromethamine). Time to peak plasma concentration: 4 hr. Bioavailability: Approx 30-40%.
Distribution: Widely distributed in body fluids including CSF and bile. Crosses the placenta and enters breast milk (small amounts). Volume of distribution: 0.3 L/kg.
Metabolism: Not metabolised by the liver.
Excretion: Via urine, as unchanged drug. Plasma half-life: Approx 2 hr.

Source: National Center for Biotechnology Information. PubChem Database. Fosfomycin, CID=446987, https://pubchem.ncbi.nlm.nih.gov/compound/Fosfomycin (accessed on Jan. 21, 2020)

Oral powd: Store at 25°C. Reconstituted soln for infusion: Store between 2-8°C; stable for 12 hr. Protect from light.

Urinary Antiseptics / Other Antibiotics

Anon. Fosfomycin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 16/10/2014.

Buckingham R (ed). Fosfomycin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com . Accessed 16/10/2014.

McEvoy GK, Snow EK, Miller J et al (eds). Fosfomycin Tromethamine. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com . Accessed 16/10/2014.

Monurol Powder (Forest Laboratories). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 16/10/2014.