Tigecycline exerts its antibacterial effect by inhibiting bacterial protein synthesis. It binds to the 30S ribosomal subunit, blocking the entry of aminoacyl-tRNA into the A site of the ribosome. This prevents the addition of amino acids to the growing peptide chain, ultimately inhibiting protein synthesis. Tigecycline is bacteriostatic (inhibits bacterial growth) against most organisms.

Tigecycline has a broad spectrum of activity, including:

• Gram-positive bacteria: Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and Streptococcus species.
• Gram-negative bacteria: Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Enterobacter species (including some carbapenem-resistant strains).
• Anaerobic bacteria: Bacteroides fragilis, Clostridium species.
• Atypical pathogens: Mycoplasma pneumoniae, Chlamydia species.

Tigecycline is not affected by many common resistance mechanisms, such as efflux pumps and ribosomal protection proteins, which makes it effective against multidrug-resistant organisms.

Tigecycline is approved for the treatment of complicated infections caused by susceptible organisms. Its clinical applications include:

1. Complicated Skin and Soft Tissue Infections (cSSTIs):
   • Infections caused by MRSA, Streptococcus pyogenes, and other susceptible organisms.
2. Complicated Intra-Abdominal Infections (cIAIs):
   • Infections caused by E. coli, Klebsiella species, Bacteroides fragilis, and other susceptible organisms.
3. Community-Acquired Bacterial Pneumonia (CABP):
   • Infections caused by Streptococcus pneumoniae, Haemophilus influenzae, and Legionella pneumophila.
4. Off-Label Uses:
   • Infections caused by multidrug-resistant Gram-negative bacteria, such as carbapenem-resistant Enterobacteriaceae (CRE) and Acinetobacter baumannii.
   • Bone and joint infections.

Tigecycline is administered intravenously (IV) due to poor oral bioavailability. The standard dosing regimen is as follows:

Adults:

• Loading dose: 100 mg IV as a single dose.
• Maintenance dose: 50 mg IV every 12 hours.
• Duration of therapy: 5–14 days, depending on the infection and clinical response.

Children:

• Tigecycline is not approved for use in children under 18 years of age.

Renal and Hepatic Impairment:

• Renal impairment: No dose adjustment is required.
• Hepatic impairment:
  • Mild to moderate impairment (Child-Pugh A or B): No dose adjustment.
  • Severe impairment (Child-Pugh C): Reduce the maintenance dose to 25 mg every 12 hours.

Tigecycline is generally well-tolerated, but it can cause several adverse effects:

1. Gastrointestinal Effects:
   • Nausea and vomiting are the most common side effects.
   • Diarrhea and abdominal pain may also occur.
2. Hepatotoxicity:
   • Elevated liver enzymes (ALT, AST) and bilirubin have been reported.
   • Monitor liver function tests during therapy.
3. Pancreatitis:
   • Rare cases of acute pancreatitis have been reported.
4. Hematologic Effects:
   • Anemia, thrombocytopenia, and leukopenia may occur.
5. Allergic Reactions:
   • Rash, pruritus, and, rarely, anaphylaxis.
6. Other Effects:
   • Headache, dizziness, and injection site reactions.

1. Mortality Risk:
   • Tigecycline has been associated with an increased risk of all-cause mortality in some clinical trials. Use should be reserved for situations where alternative treatments are not suitable.
2. Hepatic Impairment:
   • Use with caution in patients with severe hepatic impairment (Child-Pugh C). Dose reduction is required.
3. Pregnancy and Lactation:
   • Tigecycline should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
   • It is excreted in breast milk; caution is advised during lactation.
4. Superinfections:
   • Prolonged use may result in the overgrowth of nonsusceptible organisms, including fungi.
5. Pancreatitis:
   • Monitor for signs and symptoms of pancreatitis, especially in patients with risk factors.

Tigecycline has a low potential for drug interactions due to its limited metabolism by cytochrome P450 enzymes. However, the following interactions should be considered:

1. Warfarin:
   • Tigecycline may enhance the anticoagulant effect of warfarin. Monitor INR closely.
2. Oral Contraceptives:
   • Tigecycline may reduce the efficacy of oral contraceptives. Advise patients to use alternative or additional contraceptive methods.
3. Other Antibiotics:
   • Concurrent use with other bacteriostatic antibiotics (e.g., tetracyclines) may reduce the efficacy of tigecycline.

Tigecycline is available under various generic names, including:

• Tigecycline

It is marketed under the brand name Tygacil.