Among beta-lactam antibiotics, which is the most common cause of drug-induced hepatotoxicity?

Explanation

## Beta-Lactam-Induced Hepatotoxicity **Key Point:** Amoxicillin-clavulanate is the most common beta-lactam antibiotic causing drug-induced liver injury (DILI), with an incidence of 1–3 cases per 100,000 prescriptions. ### Mechanism of Hepatotoxicity Amoxicillin-clavulanate causes hepatotoxicity through: - **Clavulanate component** — the primary culprit, not amoxicillin alone - Cholestatic or mixed hepatocellular-cholestatic pattern - Idiosyncratic reaction (not dose-dependent) - Risk increases with age >60 years and prolonged exposure ### Clinical Features | Feature | Details | |---------|----------| | **Onset** | 1–6 weeks after initiation; can occur up to 6 weeks post-discontinuation | | **Pattern** | Cholestasis > hepatocellular injury | | **Severity** | Usually mild; fulminant hepatic failure rare but reported | | **Recovery** | Typically complete within 3–6 months | **High-Yield:** Amoxicillin-clavulanate is the **most hepatotoxic beta-lactam** — this is a frequently tested fact in NEET PG. ### Why Other Beta-Lactams Are Safer - **Cephalosporins** (cephalexin, ceftriaxone): minimal hepatotoxicity; <0.1 cases per 100,000 - **Penicillins alone** (amoxicillin, ampicillin without clavulanate): very low hepatotoxicity - **Carbapenems** (meropenem, imipenem): rare hepatotoxicity; <0.01 cases per 100,000 - **Azlocillin** (antipseudomonal penicillin): hepatotoxicity not a recognized adverse effect **Clinical Pearl:** Always monitor LFTs in patients on prolonged amoxicillin-clavulanate, especially if >60 years old or with pre-existing liver disease.