Fosfomycin

Oral
Acute uncomplicated cystitis in women
Adult: As fosfomycin trometamol granules: 3 g (fosfomycin base) as a single dose.
Child: >12 years Same as adult dose.
Renal impairment: Patients undergoing haemodialysis: Contraindicated.

CrCl (ml/min)	Dosage Recommendation
<10	Contraindicated.

Reconstitution: Granules for oral solution: Dissolve the contents of a sachet in appropriate volume of water as indicated on the label.

Oral
Prophylaxis of urinary tract infections
Adult: In diagnostic and surgical transurethral procedures: As fosfomycin trometamol granules: 3 g (fosfomycin base) to be given 3 hours before procedure. May give another 3 g, 24 hours after procedure.
Renal impairment: Patients undergoing haemodialysis: Contraindicated.

CrCl (ml/min)	Dosage Recommendation
<10	Contraindicated.

Reconstitution: Granules for oral solution: Dissolve the contents of a sachet in appropriate volume of water as indicated on the label.

Intravenous
Hospital-acquired pneumonia
Adult: As fosfomycin disodium: In cases where commonly recommended agents for initial treatment is considered inappropriate or ineffective: 12-24 g (fosfomycin base) daily, given in 2-3 divided doses; high-dose regimen is used in severe infections known or suspected to be caused by less sensitive organisms. Max: 8 g/dose. Treatment duration may vary depending on the type or severity of infection and patient's response. Method of administration may vary among individual products and between countries (refer to specific product guidelines).
Child: Premature neonates <40 weeks (sum of gestational and postnatal age) 100 mg/kg daily, given in 2 divided doses; Neonates 40-44 weeks (sum of gestational and postnatal age) 200 mg/kg daily, given in 3 divided doses; 1-12 months weighing <10 kg: 200-300 mg/kg daily, given in 3 divided doses; 1-<12 years weighing 10-40 kg: 200-400 mg/kg daily, given in 3-4 divided doses; ≥12 years weighing ≥40 kg: Same as adult dose. May consider high-dose regimen for severe infections suspected or known to be caused by organisms with moderate susceptibility. Doses are expressed as fosfomycin base. Method of administration may vary among individual products and between countries (refer to specific product guidelines).
Renal impairment: Patient undergoing chronic intermittent haemodialysis (every 48 hours): Give 2 g at the end of each session.

CrCl (ml/min)	Dosage Recommendation
10	Give 20% of the usual daily dose in 1-2 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
20	Give 40% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
30	Give 60% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
40	Give 70% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.

Reconstitution: Powder for solution for infusion: Reconstitute then dilute with appropriate amount of water for inj, dextrose 5% or 10% inj to prepare the desired concentration. Instruction for reconstitution may vary among individual products and between countries (refer to specific product guidelines).

Intravenous
Osteomyelitis
Adult: As fosfomycin disodium: In cases where commonly recommended agents for initial treatment is considered inappropriate or ineffective: 12-24 g (fosfomycin base) daily, given in 2-3 divided doses; high-dose regimen is used in severe infections known or suspected to be caused by less sensitive organisms. Max: 8 g/dose. Treatment duration may vary depending on the type or severity of infection and patient's response. Method of administration may vary among individual products and between countries (refer to specific product guidelines).
Child: Premature neonates <40 weeks (sum of gestational and postnatal age) 100 mg/kg daily, given in 2 divided doses; Neonates 40-44 weeks (sum of gestational and postnatal age) 200 mg/kg daily, given in 3 divided doses; 1-12 months weighing <10 kg: 200-300 mg/kg daily, given in 3 divided doses; 1-<12 years weighing 10-40 kg: 200-400 mg/kg daily, given in 3-4 divided doses; ≥12 years weighing ≥40 kg: Same as adult dose. May consider high-dose regimen for severe infections suspected or known to be caused by organisms with moderate susceptibility. Doses are expressed as fosfomycin base. Method of administration may vary among individual products and between countries (refer to specific product guidelines).
Renal impairment: Patient undergoing chronic intermittent haemodialysis (every 48 hours): Give 2 g at the end of each session.

CrCl (ml/min)	Dosage Recommendation
10	Give 20% of the usual daily dose in 1-2 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
20	Give 40% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
30	Give 60% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
40	Give 70% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.

Reconstitution: Powder for solution for infusion: Reconstitute then dilute with appropriate amount of water for inj, dextrose 5% or 10% inj to prepare the desired concentration. Instruction for reconstitution may vary among individual products and between countries (refer to specific product guidelines).

Intravenous
Bone and joint infections
Adult: As fosfomycin disodium: In cases where commonly recommended agents for initial treatment is considered inappropriate or ineffective: 12-24 g (fosfomycin base) daily, given in 2-3 divided doses; high-dose regimen is used in severe infections known or suspected to be caused by less sensitive organisms. Max: 8 g/dose. Treatment duration may vary depending on the type or severity of infection and patient's response. Method of administration may vary among individual products and between countries (refer to specific product guidelines).
Child: Premature neonates <40 weeks (sum of gestational and postnatal age) 100 mg/kg daily, given in 2 divided doses; Neonates 40-44 weeks (sum of gestational and postnatal age) 200 mg/kg daily, given in 3 divided doses; 1-12 months weighing <10 kg: 200-300 mg/kg daily, given in 3 divided doses; 1-<12 years weighing 10-40 kg: 200-400 mg/kg daily, given in 3-4 divided doses; ≥12 years weighing ≥40 kg: Same as adult dose. May consider high-dose regimen for severe infections suspected or known to be caused by organisms with moderate susceptibility. Doses are expressed as fosfomycin base. Method of administration may vary among individual products and between countries (refer to specific product guidelines).
Renal impairment: Patient undergoing chronic intermittent haemodialysis (every 48 hours): Give 2 g at the end of each session.

CrCl (ml/min)	Dosage Recommendation
10	Give 20% of the usual daily dose in 1-2 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
20	Give 40% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
30	Give 60% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
40	Give 70% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.

Reconstitution: Powder for solution for infusion: Reconstitute then dilute with appropriate amount of water for inj, dextrose 5% or 10% inj to prepare the desired concentration. Instruction for reconstitution may vary among individual products and between countries (refer to specific product guidelines).

Intravenous
Complicated urinary tract infections
Adult: As fosfomycin disodium: In cases where commonly recommended agents for initial treatment is considered inappropriate or ineffective: 12-24 g (fosfomycin base) daily, given in 2-3 divided doses; high-dose regimen is used in severe infections known or suspected to be caused by less sensitive organisms. Max: 8 g/dose. Treatment duration may vary depending on the type or severity of infection and patient's response. Method of administration may vary among individual products and between countries (refer to specific product guidelines).
Child: Premature neonates <40 weeks (sum of gestational and postnatal age) 100 mg/kg daily, given in 2 divided doses; Neonates 40-44 weeks (sum of gestational and postnatal age) 200 mg/kg daily, given in 3 divided doses; 1-12 months weighing <10 kg: 200-300 mg/kg daily, given in 3 divided doses; 1-<12 years weighing 10-40 kg: 200-400 mg/kg daily, given in 3-4 divided doses; ≥12 years weighing ≥40 kg: Same as adult dose. May consider high-dose regimen for severe infections suspected or known to be caused by organisms with moderate susceptibility. Doses are expressed as fosfomycin base. Method of administration may vary among individual products and between countries (refer to specific product guidelines).
Renal impairment: Patient undergoing chronic intermittent haemodialysis (every 48 hours): Give 2 g at the end of each session.

CrCl (ml/min)	Dosage Recommendation
10	Give 20% of the usual daily dose in 1-2 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
20	Give 40% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
30	Give 60% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
40	Give 70% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.

Reconstitution: Powder for solution for infusion: Reconstitute then dilute with appropriate amount of water for inj, dextrose 5% or 10% inj to prepare the desired concentration. Instruction for reconstitution may vary among individual products and between countries (refer to specific product guidelines).

Intravenous
Bacterial meningitis
Adult: As fosfomycin disodium: In cases where commonly recommended agents for initial treatment is considered inappropriate or ineffective: 16-24 g (fosfomycin base) daily, given in 3-4 divided doses; high-dose regimen is used in severe infections known or suspected to be caused by less sensitive organisms. Max: 8 g/dose. Treatment duration may vary depending on the type or severity of infection and patient's response. Method of administration may vary among individual products and between countries (refer to specific product guidelines).
Child: Premature neonates <40 weeks (sum of gestational and postnatal age) 100 mg/kg daily, given in 2 divided doses; Neonates 40-44 weeks (sum of gestational and postnatal age) 200 mg/kg daily, given in 3 divided doses; 1-12 months weighing <10 kg: 200-300 mg/kg daily, given in 3 divided doses; 1-<12 years weighing 10-40 kg: 200-400 mg/kg daily, given in 3-4 divided doses; ≥12 years weighing ≥40 kg: Same as adult dose. May consider high-dose regimen for severe infections suspected or known to be caused by organisms with moderate susceptibility. Doses are expressed as fosfomycin base. Method of administration may vary among individual products and between countries (refer to specific product guidelines).
Renal impairment: Patient undergoing chronic intermittent haemodialysis (every 48 hours): Give 2 g at the end of each session.

CrCl (ml/min)	Dosage Recommendation
10	Give 20% of the usual daily dose in 1-2 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
20	Give 40% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
30	Give 60% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.
40	Give 70% of the usual daily dose in 2-3 divided doses. 1st dose (loading dose) should be doubled; Max 8 g.

Reconstitution: Powder for solution for infusion: Reconstitute then dilute with appropriate amount of water for inj, dextrose 5% or 10% inj to prepare the desired concentration. Instruction for reconstitution may vary among individual products and between countries (refer to specific product guidelines).

Should be taken on an empty stomach (i.e. At least one hour before food or two hours after food).

Hypersensitivity. Oral: Severe renal impairment (CrCl <10 mL/min); patient undergoing haemodialysis.

Patient with cardiac insufficiency, hypertension, hyperaldosteronism, hypernatraemia, pulmonary oedema (IV). Not indicated for pyelonephritis or perinephric abscess (oral). Renal impairment or hepatic cirrhosis (IV). Premature neonates, neonates (IV); children (IV or oral [when used in acute uncomplicated cystitis]). Pregnancy and lactation. Patient Counselling This drug may cause dizziness, if affected, do not drive or operate machinery. Monitoring Parameters Perform culture and susceptibility tests; consult local institutional recommendations before treatment initiation due to antibiotic resistance risks. Evaluate the effectiveness of treatment. Monitor for severe or bloody diarrhoea and perform a test to check for the presence of Clostridium difficile. IV: Monitor serum electrolyte and fluid balance, leucocyte count; renal or liver function.

Significant: Hepatic injury (including steatosis, hepatitis); fungal or bacterial superinfection (prolonged use). IV: Electrolyte abnormalities (e.g. hypernatraemia, hypokalaemia); haematological reactions (e.g. neutropenia, agranulocytosis). Gastrointestinal disorders: Diarrhoea, nausea, abdominal pain, dyspepsia, vomiting; dysgeusia (IV). General disorders and administration site conditions: Inj site phlebitis, asthenia (IV). Nervous system disorders: Headache, dizziness. Reproductive system and breast disorders: Vulvovaginitis (oral). Skin and subcutaneous tissue disorders: Erythematous eruption (IV).
Potentially Fatal: Hypersensitivity reactions (including anaphylaxis, anaphylactic shock); Clostridium difficile-associated diarrhoea and pseudomembranous colitis.

Symptoms: Oral: Vestibular loss, impaired hearing, metallic taste and generalised decrease in perception of taste. IV: Hypotonia, electrolyte disturbance, somnolence, thrombocytopenia and hypoprothrombinaemia. Management: Symptomatic and supportive treatment. Rehydrate to promote urinary elimination; may perform haemodialysis.

Decreased serum and urine levels with metoclopramide; may also result in the same effect with other drugs that increase gastrointestinal motility (e.g. bethanechol, cisapride, domperidone, laxatives).

Food reduces the rate and extent of absorption.

Fosfomycin acts on the 1st stage of intracellular bacterial cell wall synthesis. It inactivates pyruvyl transferase, an enzyme critical for the synthesis of bacterial cell wall, thereby causing a bactericidal effect on the proliferating pathogen.
Absorption: Rapidly absorbed from the gastrointestinal tract. Food reduces the rate and extent of absorption. Bioavailability: 37% (fasting); 30% (with food). Time to peak plasma concentration: 2 hours (oral).
Distribution: Widely distributed in the kidneys, bladder wall, prostate, seminal vesicles and body fluids including CSF. Crosses the placenta and enters breast milk (small amounts). Volume of distribution: 90-180 L (oral); 0.3 L/kg (IV).
Metabolism: Not metabolised.
Excretion: Oral: Mainly via urine (38% as unchanged drug); faeces (18%, as unchanged drug); IV: Via urine (80-90% as unchanged drug). Elimination half-life: 3-8 hours (oral); approx 2 hours (IV).

Intravenous: Vial: Store between 15-30°C. Protect from light. Storage recommendations may vary among individual products and between countries (refer to specific product guidelines). Oral: Oral granules: Store below 30°C. Protect from light. Storage recommendations may vary among individual products and between countries (refer to specific product guidelines).

Other Antibiotics

S02AA17 - fosfomycin ; Belongs to the class of antiinfectives used in the treatment of ear infections.
J01XX01 - fosfomycin ; Belongs to the class of other antibacterials. Used in the systemic treatment of infections.