Ketek

Generic name: telithromycin

Drug class: ketolide antibiotic

Dosage form: tablets (400 mg)

Root of administration: oral

Dose: 800 mg once daily for 10 days (community-acquired bacterial pneumonia); 400 mg twice daily for 7–10 days (acute bacterial exacerbations of chronic bronchitis); 400 mg twice daily for 5–10 days (pharyngitis/tonsillitis)

Mechanism of action: binds to the 50S bacterial ribosomal subunit, inhibiting protein synthesis by blocking peptidyl transferase and translocation; retains activity against some macrolide-resistant strains

Drug usage cases:

• Community-acquired bacterial pneumonia
• Acute bacterial exacerbations of chronic bronchitis
• Pharyngitis and tonsillitis
• Off-label: skin and soft tissue infections; sinusitis; atypical mycobacterial infections (varies by indication; consult label)

Drug contra indications:

• Hypersensitivity to telithromycin, ketolides, or macrolides
• Myasthenia gravis or history of myasthenia gravis
• Severe hepatic impairment
• Known QT prolongation or history of torsades de pointes
• Concomitant use with CYP3A4 substrates: cisapride, pimozide, ergot alkaloids, lovastatin, simvastatin

Side effects:

• Gastrointestinal: diarrhea, nausea, vomiting, abdominal pain, dyspepsia
• Hepatic: elevated transaminases, hepatitis, cholestatic jaundice, hepatic failure
• Cardiac: QT interval prolongation, arrhythmias
• Central nervous system: headache, dizziness, insomnia, visual disturbances (blurred vision, difficulty focusing)
• Auditory: tinnitus
• Dermatologic: rash, Stevens–Johnson syndrome, toxic epidermal necrolysis
• Hematologic: eosinophilia, leukopenia
• Neuromuscular: exacerbation of myasthenia gravis
• Other: taste perversion, fatigue

Warnings:

• Severe hepatotoxicity: monitor liver function; discontinue if signs of liver injury occur
• QT prolongation and torsades de pointes: use with caution in patients with risk factors
• Contraindicated in myasthenia gravis due to risk of exacerbation
• Numerous CYP3A4 interactions: review all concomitant medications
• Use caution in hepatic impairment
• Immune thrombocytopenia reported: monitor if bleeding/bruising occurs
• Visual disturbances reported: advise patients
• Clostridioides difficile–associated diarrhea may occur

Use during pregnancy or breastfeeding:

Pregnancy: Category C. Animal studies have shown adverse fetal effects; no adequate human data. Use only if benefits justify potential fetal risk.

Breastfeeding: Excreted in human milk; potential for serious adverse reactions in nursing infants. Discontinue breastfeeding during treatment.