Usage
Ofloxacin is a broad-spectrum antibiotic belonging to the fluoroquinolone class. It is prescribed for various bacterial infections, including:
- Lower respiratory tract infections (e.g., bronchitis, pneumonia)
- Urinary tract infections (e.g., cystitis, pyelonephritis, prostatitis)
- Sexually transmitted infections (e.g., gonorrhea, chlamydia, cervicitis, urethritis)
- Skin and skin structure infections
- Infectious diarrhea
- Acute pelvic inflammatory disease
Pharmacological Classification: Fluoroquinolone antibiotic.
Mechanism of Action: Ofloxacin inhibits bacterial DNA gyrase and topoisomerase IV, enzymes essential for bacterial DNA replication and repair. This inhibition leads to bacterial cell death.
Alternate Names
Ofloxacin is also known as Floxin and Floxin I.V (brand names).
How It Works
Pharmacodynamics: Ofloxacin exerts its bactericidal effect by inhibiting bacterial DNA gyrase and topoisomerase IV. This disrupts DNA replication and repair, ultimately leading to bacterial cell death.
Pharmacokinetics:
- Absorption: Ofloxacin is well-absorbed orally, reaching peak plasma concentrations within 1-2 hours. Food may slightly delay absorption but does not significantly affect overall bioavailability.
- Metabolism: Ofloxacin undergoes minimal hepatic metabolism.
- Elimination: Primarily eliminated renally (via urine) as unchanged drug. Some elimination occurs through feces.
Mode of Action: Ofloxacin targets bacterial DNA gyrase and topoisomerase IV. These enzymes are crucial for bacterial DNA replication, transcription, and repair. By inhibiting their activity, ofloxacin prevents the supercoiling and relaxation of DNA necessary for cell function, resulting in the death of bacterial cells.
Receptor Binding/Enzyme Inhibition: Ofloxacin inhibits bacterial DNA gyrase and topoisomerase IV.
Elimination Pathways: Predominantly renal excretion; minor fecal excretion.
Dosage
Standard Dosage
Adults:
- Most Infections: 200-400 mg every 12 hours for 7-14 days (depending on the infection). Up to a maximum of 800mg daily.
- Gonorrhea: 400 mg as a single dose.
Children:
Ofloxacin is generally contraindicated in children and adolescents under 18 years due to the risk of cartilage damage. In some cases, it may be used in children if the benefits outweigh the risks and no safer alternatives are available. Dosage must be determined by a doctor.
Special Cases:
- Elderly Patients: Dose adjustments based on renal function are often necessary.
- Patients with Renal Impairment: Dosage adjustment based on creatinine clearance is necessary.
- CrCl 20-50 mL/min: Administer standard dose every 24 hours.
- CrCl < 20 mL/min: Administer one-half the standard dose every 24 hours.
- Patients with Hepatic Dysfunction: A maximum dose of 400 mg/day is recommended for patients with severe hepatic impairment.
- Patients with Comorbid Conditions: Careful monitoring and potential dose adjustments may be needed based on the specific comorbidity.
Clinical Use Cases
Dosage recommendations for specific medical settings like intubation, surgical procedures, mechanical ventilation, and ICU use must be determined by the treating physician based on individual patient needs.
Dosage Adjustments
Dose modifications may be required for renal/hepatic impairment.
Side Effects
Common Side Effects:
- Nausea
- Diarrhea
- Headache
- Dizziness
- Insomnia
- Vaginal itching or discharge
Rare but Serious Side Effects:
- Tendinitis and tendon rupture
- Peripheral neuropathy
- Seizures
- QT prolongation
- Clostridium difficile-associated diarrhea
- Hypersensitivity reactions (including Stevens-Johnson syndrome)
Long-Term Effects:
Peripheral neuropathy and tendon damage may persist even after discontinuation of ofloxacin.
Adverse Drug Reactions (ADR):
Serious ADRs like tendon rupture, severe hypersensitivity reactions, and QT prolongation require immediate medical attention.
Contraindications
- Hypersensitivity to ofloxacin or other fluoroquinolones.
- Myasthenia gravis.
- Epilepsy or conditions predisposing to seizures.
- History of QT prolongation.
- Pregnancy and breastfeeding.
- Children and adolescents under 18 years of age (generally contraindicated).
Drug Interactions
- Antacids, Sucralfate, Multivitamins/Minerals: These can decrease ofloxacin absorption. Separate administration by at least 2 hours.
- Theophylline: Ofloxacin can increase theophylline levels, leading to toxicity. Monitor theophylline levels closely.
- Warfarin: Ofloxacin can enhance the effects of warfarin, increasing the risk of bleeding. Monitor INR closely.
- NSAIDs: Concurrent use with NSAIDs can increase the risk of seizures.
- Antiarrhythmic Drugs: Ofloxacin can prolong the QT interval and increase the risk of arrhythmias when used with other drugs that also prolong the QT interval (e.g. amiodarone, sotalol, quinidine).
- CYP450 Interactions: Ofloxacin is a weak inhibitor of CYP1A2 and can potentially interact with drugs metabolized by this enzyme.
Pregnancy and Breastfeeding
Ofloxacin is contraindicated in pregnancy and breastfeeding due to potential risks to the fetus/infant (cartilage damage, arthropathy).
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial DNA gyrase and topoisomerase IV.
- Side Effects: Nausea, diarrhea, headache, dizziness, insomnia, tendinitis, peripheral neuropathy.
- Contraindications: Hypersensitivity, myasthenia gravis, epilepsy, QT prolongation, pregnancy, breastfeeding, children <18 years.
- Drug Interactions: Antacids, theophylline, warfarin, NSAIDs, antiarrhythmics.
- Pregnancy & Breastfeeding: Contraindicated.
- Dosage: Adults: 200-400 mg every 12 hours; adjustments for renal/hepatic impairment.
- Monitoring Parameters: Renal function, liver function, signs of tendinitis/neuropathy, ECG (for QT prolongation).
Popular Combinations
Information on popular combinations is not available in the provided sources.
Precautions
- Avoid direct sunlight exposure due to photosensitivity risk.
- Discontinue at the first sign of tendinitis or neuropathy.
- Monitor for signs of Clostridium difficile-associated diarrhea.
- Caution in patients with CNS disorders, renal/hepatic impairment.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Ofloxacin?
A: The standard adult dosage is 200-400 mg every 12 hours. Dosages need adjustments for renal/hepatic impairment. It is contraindicated in children under 18.
Q2: What are the most common side effects of Ofloxacin?
A: The most common side effects include nausea, diarrhea, headache, dizziness, and insomnia.
Q3: Can Ofloxacin be used during pregnancy or breastfeeding?
A: No, Ofloxacin is contraindicated during pregnancy and breastfeeding.
A: Tendinitis, tendon rupture, peripheral neuropathy, seizures, and QT prolongation require immediate medical attention.
Q5: What are the major drug interactions with Ofloxacin?
A: Ofloxacin interacts with antacids, sucralfate, theophylline, warfarin, NSAIDs, and antiarrhythmic drugs.
Q6: What is the mechanism of action of Ofloxacin?
A: Ofloxacin inhibits bacterial DNA gyrase and topoisomerase IV, preventing DNA replication and repair, ultimately leading to bacterial cell death.
Q7: What precautions should be taken while prescribing Ofloxacin?
A: Monitor renal and hepatic function, avoid direct sunlight exposure, and discontinue at the first sign of tendinitis, neuropathy, or C. difficile infection. Use cautiously with CNS disorders.
Q8: Is Ofloxacin effective against all types of bacterial infections?
A: No, Ofloxacin is a broad-spectrum antibiotic but not effective against all bacteria. Susceptibility testing is recommended to ensure appropriate use.
Q9: How long should a patient typically take Ofloxacin?
A: Treatment duration typically ranges from 7 to 14 days, depending on the type and severity of the infection. Prostatitis may require a longer duration (up to 6 weeks).
