Used for the treatment of acute bacterial infections of the ear.

Chloramphenicol inhibits bacterial protein synthesis by binding to the 50S subunit of the bacterial ribosome, thereby preventing peptide bond formation via inhibition of peptidyl transferase activity. It exhibits both bacteriostatic and bactericidal effects against organisms such as H. influenzae, N. meningitidis, and S. pneumoniae.

Lidocaine is an amide-type local anesthetic. It stabilizes neuronal membranes by inhibiting sodium ion movement required for nerve impulse conduction. In the heart, lidocaine reduces ventricular depolarization during diastole and suppresses automaticity in the His-Purkinje system, thereby shortening the duration of action potential and effective refractory period.

Otic/Aural Otitis externa: Instill 2–3 drops into the ear bid–tid.

Chloramphenicol may reduce the effectiveness of iron and vitamin B12 in anaemic patients. Phenobarbitone and rifampicin can decrease its efficacy. It may also reduce the effectiveness of oral contraceptives.

Potentially serious interactions include increased effects of oral anticoagulants, oral hypoglycaemic agents, and phenytoin. Concomitant use with drugs that suppress bone marrow function should be avoided

• History of hypersensitivity or toxic reaction to the drug
• Perforated ear drum
• Herpes simplex and other viral infections of the eye or ear
• Fungal infections (mycosis)

Ototoxicity may occur.

Pregnancy Category C & B. Animal studies have shown adverse fetal effects, and there are no adequate controlled studies in humans; however, the drug may be used if the potential benefit justifies the risk.

Some studies indicate no clear fetal risk, while others suggest possible adverse effects; therefore, use should be carefully considered in pregnancy.

Avoid prolonged use. Discontinue immediately if signs of local hypersensitivity develop.

Aural Anti-bacterial preparations