Usage
Gemifloxacin is a fluoroquinolone antibiotic prescribed for the treatment of acute bacterial exacerbations of chronic bronchitis and mild to moderate community-acquired pneumonia (CAP). It is effective against a broad spectrum of bacterial pathogens, including Streptococcus pneumoniae (including multi-drug resistant strains), Haemophilus influenzae, Moraxella catarrhalis, Chlamydia pneumoniae, Mycoplasma pneumoniae, and Klebsiella pneumoniae. It exhibits activity against some strains of Staphylococcus aureus (MSSA) and atypical pathogens like Legionella pneumophila.
Alternate Names
Gemifloxacin is the generic name. It is commonly marketed under the brand name Factive.
How It Works
Pharmacodynamics: Gemifloxacin exerts its bactericidal effect by inhibiting bacterial DNA gyrase and topoisomerase IV, essential enzymes for bacterial DNA replication, transcription, repair, and recombination.
Pharmacokinetics:
- Absorption: Gemifloxacin is well-absorbed orally, with peak plasma concentrations achieved approximately 1 to 2 hours after administration. Food does not significantly affect absorption.
- Distribution: It is widely distributed throughout the body, including lung tissue.
- Metabolism: Gemifloxacin undergoes minimal hepatic metabolism.
- Elimination: Primarily eliminated through renal excretion (approximately 60-70%) and to a lesser extent through feces. The elimination half-life is approximately 7 hours, allowing for once-daily dosing.
Dosage
Standard Dosage
Adults:
- Acute Bacterial Exacerbations of Chronic Bronchitis: 320 mg orally once daily for 5 days.
- Community-Acquired Pneumonia: 320 mg orally once daily for 5-7 days (7 days for infections suspected or proven to be caused by multi-drug resistant Streptococcus pneumoniae, Klebsiella pneumoniae, or Moraxella catarrhalis).
Children:
The safety and efficacy of gemifloxacin have not been established in children younger than 18 years.
Special Cases:
- Elderly Patients: No dosage adjustment is necessary based solely on age. However, close monitoring is recommended due to the potential for increased risk of certain adverse effects.
- Patients with Renal Impairment: For creatinine clearance (CrCl) ≤ 40 mL/min, the dose should be reduced to 160 mg once daily.
- Patients with Hepatic Dysfunction: No dosage adjustment is necessary.
- Patients with Comorbid Conditions: Use with caution in patients with a history of seizures, myasthenia gravis, or tendon disorders. Avoid in patients with QT prolongation or uncorrected electrolyte abnormalities.
Clinical Use Cases
Dosing remains consistent with standard recommendations for adults for clinical scenarios such as intubation, surgical procedures, mechanical ventilation, ICU use, and emergency situations.
Dosage Adjustments
Dose modifications are primarily necessary for patients with renal impairment, as described above.
Side Effects
Common Side Effects:
Nausea, diarrhea, vomiting, abdominal pain, headache, dizziness, rash.
Rare but Serious Side Effects:
- Tendinitis or tendon rupture
- Peripheral neuropathy (numbness, tingling, burning pain in hands or feet)
- CNS effects (seizures, hallucinations, anxiety, depression, suicidal thoughts)
- QT interval prolongation
- Hypersensitivity reactions (rash, itching, swelling, severe skin reactions)
- Clostridium difficile-associated diarrhea
- Hepatotoxicity
- Blood dyscrasias
Long-Term Effects:
Peripheral neuropathy and tendon damage can be irreversible.
Adverse Drug Reactions (ADR):
Anaphylaxis, Stevens-Johnson syndrome, toxic epidermal necrolysis.
Contraindications
- Hypersensitivity to gemifloxacin or other fluoroquinolones.
- Myasthenia gravis.
- History of QT prolongation.
Drug Interactions
Gemifloxacin interacts with numerous medications, including antacids, iron supplements, multivitamins containing zinc or iron, sucralfate, didanosine, warfarin, theophylline, probenecid, and drugs known to prolong the QT interval (e.g., amiodarone, quinidine, thioridazine).
Pregnancy and Breastfeeding
- Pregnancy: Gemifloxacin is classified as Pregnancy Category C. Animal studies have shown potential for fetal harm. It should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
- Breastfeeding: It is unknown whether gemifloxacin is excreted in human milk. Caution is advised when administering to breastfeeding mothers, and alternative agents may be preferred.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial DNA gyrase and topoisomerase IV.
- Side Effects: Nausea, diarrhea, headache, dizziness, rash; serious side effects include tendinitis/tendon rupture, peripheral neuropathy, CNS effects.
- Contraindications: Hypersensitivity to fluoroquinolones, myasthenia gravis.
- Drug Interactions: Antacids, metal cations, warfarin, QT prolonging drugs.
- Pregnancy & Breastfeeding: Category C; use with caution in breastfeeding.
- Dosage: 320 mg once daily for 5-7 days for adults. Adjust dose for renal impairment.
- Monitoring Parameters: Renal function, liver function, ECG (in patients at risk for QT prolongation), signs of tendonitis/rupture, peripheral neuropathy, and CNS effects.
Popular Combinations
No specific popular combinations are associated with Gemifloxacin.
Precautions
- Discontinue gemifloxacin at the first sign of rash, jaundice, or other hypersensitivity reactions.
- Advise patients to avoid excessive sun exposure.
- Monitor for signs of tendonitis or tendon rupture.
- Monitor for peripheral neuropathy and CNS side effects.
- Assess for myasthenia gravis before initiating therapy.
FAQs
Q1: What is the recommended dosage for Gemifloxacin?
A: Adults: 320 mg orally once daily. Adjust for renal impairment (CrCl ≤ 40 mL/min: 160 mg once daily). Not established for children.
Q2: What are the most serious side effects of Gemifloxacin?
A: Tendinitis/tendon rupture, peripheral neuropathy, CNS effects (seizures, hallucinations, depression), QT prolongation, serious hypersensitivity reactions.
Q3: Can Gemifloxacin be used in patients with liver disease?
A: Yes, no dosage adjustment is necessary for patients with hepatic impairment.
Q4: What are the contraindications to Gemifloxacin use?
A: Hypersensitivity to fluoroquinolones, myasthenia gravis.
Q5: Does Gemifloxacin interact with antacids?
A: Yes, antacids containing magnesium or aluminum can reduce the absorption of gemifloxacin. Administer antacids at least 3 hours before or 2 hours after gemifloxacin.
Q6: Can Gemifloxacin be used during pregnancy?
A: It is Pregnancy Category C. Use only if the potential benefit outweighs the risk to the fetus.
Q7: Is Gemifloxacin safe for children?
A: Safety and effectiveness have not been established in children younger than 18.
Q8: What should patients be advised regarding sun exposure while taking Gemifloxacin?
A: Patients should avoid excessive sun exposure and use sunscreen due to the risk of photosensitivity reactions.
Q9: How is Gemifloxacin eliminated from the body?
A: Primarily via renal excretion (60-70%), with a smaller amount eliminated in feces.
Q10: What is the mechanism of action of Gemifloxacin?
A: Gemifloxacin inhibits bacterial DNA gyrase and topoisomerase IV, essential enzymes for bacterial DNA replication and repair.
