Moxifloxacin

Fluoroquinolones, including moxifloxacin are associated with disabling and potentially long-lasting or irreversible side effects. See Fluoroquinolone antibiotics - severe adverse effects

When using fluoroquinolones:

• DO NOT prescribe for:
  • non-severe or self-limiting infections.
  • mild to moderate infections (unless other antibiotics that are commonly recommended for these infections are considered inappropriate).
• DO read the Antimicrobial Guideline section: Fluoroquinolone antibiotics - severe adverse effects
• DO ensure penicillin allergies are properly clarified and consider de-labelling in appropriate patients to avoid the use of fluoroquinolones. See guidelines: Penicillin allergy assessment and overview and Penicillin allergy challenge and delabelling
• DO ensure all patients are given the MHRA fluoroquinolone patient leaflet (this is usually given to patients with their discharge and outpatient medications).

Oral or intravenous: 400mg OD

No dose adjustment required.

Renal impairment

No dose adjustment required.

HD/HDF/High Flux/PD: Dose as in normal renal function. Unknown dialysability.

Hepatic impairment:

• No dose adjustment required.
• Contraindicated in patients with impaired liver function (Child Pugh C) and in patients with transaminases increased more than 5 times the upper limit of normal (ULN).
• Cases of fulminant hepatitis leading to liver failure (including fatal cases) have been reported with moxifloxacin. Patients should be advised to contact their doctor if signs and symptoms of fulminant hepatic disease develop such as rapidly developing asthenia associated with jaundice, dark urine, bleeding tendency or hepatic encephalopathy.
• Liver function tests/investigations should be performed in cases where indications of liver dysfunction occur.

Pregnancy

Discuss with pharmacy

Breastfeeding

Discuss with pharmacy

The list below is not exhaustive. There are multiple interactions between moxifloxacin and other medications. Ensure interactions are checked with the BNF and SPC. Discussion with a pharmacist is advised.

Key interactions:

• NSAIDs: CAUTION. Taking NSAIDs at the same time as moxifloxacin may induce convulsions in patients with or without a history of convulsions.
• QT interval-prolongators: CAUTION. Use with caution in patients receiving other drugs known to prolong the QT interval or with other risk factors for QT interval prolongation.
• Vitamin K antagonists: anticoagulant effect enhanced- monitor INR closely and within 3-5 days of starting moxifloxacin
• Medication that can reduce potassium levels. CAUTION. Monitor potassium levels closely.

The medications listed below reduce oral moxifloxacin absorption. The oral moxifloxacin SPC states an interval of 6 hours between administration of these medications and moxifloxacin. Consult the BNF and SPC for detailed guidance on administration:

• magnesium and aluminium antacids,
• sucralfate,
• oral zinc or iron preparations,
• didanosine tablets.

• Moxifloxacin may induce convulsions in patients with or without a history of convulsions; taking NSAIDs at the same time may also induce them.
• Uncorrected hypokalaemia is a contraindication for initiating moxifloxacin as per manufacturer.
• Caution should also be used when moxifloxacin is combined with agents that cause hypokalaemia or medications associated with clinically significant bradycardia as the risk of torsades de pointes is even higher.
• Patients should be advised to avoid exposure to either extensive and/or strong sunlight or UV irradiation (e.g. tanning beds) during treatment with moxifloxacin.
• Moxifloxacin is not recommended in patients with a known history of myasthenia gravis. Fluoroquinolones, including moxifloxacin, have neuromuscular blocking activity and may exacerbate muscle weakness in patients with myasthenia gravis. 
• Use with caution in patients with G6PD deficiency or with family history of G6PD deficiency.
• Cases of bullous skin reactions like Stevens-Johnson syndrome or toxic epidermal necrolysis have been reported with fluoroquinolones. Treatment should be immediately reviewed if skin and/or mucosal reactions occur.

Broad spectrum antibiotics such as moxifloxacin carry a high risk of C.diff infection. 

Moxifloxacin has high oral bioavailability; IV moxifloxacin should only be used if the patient is NBM or there are concerns over absorption (i.e. nausea)

• Bayer plc. Moxifloxacin 400 mg film-coated tablets summary of product characteristics: Electronic Medicines Compendium [Internet]. Last revision of text 12/23 . Accessed 20/1/24. Available from: https://www.medicines.org.uk/emc/product/2358/smpc
• The Renal Drug Database. Moxifloxacin [Internet]. Last revision 14/11/2017. Accessed 20/1/24. Available from: https://renaldrugdatabase.com/monographs/moxifloxacin
• UK Medicines Information. How should antibiotics be dosed in obesity? [Internet]. 2017 [cited 2023 Nov 27] Available from: https://www.gloshospitals.nhs.uk/media/documents/Obese_Dosing_2016_update.pdf
• Meng L, Mui E, Ha DR, Stave C, Deresinski SC, Holubar M. Comprehensive guidance for antibiotic dosing in obese adults: 2022 update. Pharmacotherapy. 2023; 43(3):177-259.
• UK Teratology Information Service. Use of quinolones in pregnancy [Internet]. 2017 [cited 2023 Nov 27]. Available from: https://uktis.org/monographs/use-of-quinolones-in-pregnancy/
• Specialist Pharmacy Service. Lactation safety information – moxifloxacin [Internet]. 4/8/2020.  Accessed 20/1/24. Available from: https://www.sps.nhs.uk/medicines/moxifloxacin/
• Briggs GG, Freeman RK, Tower CV, Forinash AB. Drugs in pregnancy and lactation. 11^th ed. Philadelphia: Lippincott Williams and Wilkins; 2017.
• MHRA. Drug Safety update (January 2024) Fluoroquinolone antibiotics: must now only be prescribed when other commonly recommended antibiotics are inappropriate. Accessed HERE
• MHRA. Drug Safety update (September 2023) Fluoroquinolone antibiotics: suicidal thoughts and behaviour. Accessed HERE
• MHRA. Drug Safety update (August 2023) Fluoroquinolone antibiotics: reminder of the risk of disabling and potentially long-lasting or irreversible side effects. Accessed HERE
• MHRA. Drug Safety update (December 2020) Systemic and inhaled fluoroquinolones: small risk of heart valve regurgitation; consider other therapeutic options first in patients at risk. Accessed HERE 
• MHRA. Drug Safety update (March 2019) Fluoroquinolone antibiotics: new restrictions and precautions for use due to very rare reports of disabling and potentially long-lasting or irreversible side effects. Accessed HERE
• MHRA. Drug Safety update (November 2018) Systemic and inhaled fluoroquinolones: small increased risk of aortic aneurysm and dissection; advice for prescribing in high-risk patients. Accessed HERE