Drug Induced Lung Diseases

Oxygen: mechanism of toxicity

Induces formation of free radicals causing direct injury to endothelial cells and type I pneumocytes, resulting in alveolar‑capillary leak.

Oxygen toxicity: clinical features

Occurs in mechanically ventilated patients with high FiO₂

Oxygen: treatment

Minimize oxygen exposure: FiO2<0.6

Bleomycin: mechanism of toxicity

Chemotherapy antibiotic causing cumulative toxicity via direct cytotoxicity and free radical formation when binding Fe²⁺ and O₂. ~20% develop pulmonary disease.

Bleomycin: clinical features

Acute pneumonitis/ARDS and pulmonary fibrosis

Amiodarone: mechanism of toxicity

Iodine containing antiarrhythmic causing dose‑related interstitial pneumonitis

Amiodarone: clinical features

Dyspnea with interstitial changes, foamy macrophages

Amiodarone: treatment

Discontinue drug, steroids

Methotrexate: clinical features

Dyspnea, dry cough, fever occurring days–weeks after starting MTX

Nitrofurantoin normal use

Oral UTI antibiotic

Nitrofurantoin: clinical features of toxicity

Fever, dyspnea, dry cough with eosinophilia hours–days after starting; common drug induced pulmonary toxicity

Volatile inhalants: mechanism of toxicity

Volatile liquids (paint thinner, gasoline, glue, markers) vaporize at room temp»CNS depressants

Volatile inhalants: clinical features

Patient found obtunded with slurred speech, hypoventilation/respiratory acidosis

Nicotine/tobacco: clinical features

Acute: hypertension, tachycardia, increased myocardial work, CO‑mediated hypoxemia, alertness, appetite suppression.

Chronic: CVD, emphysema, COPD, asthma, multiple cancers (30% of cancer deaths).

Vapes/ENDS: mechanism of toxicity

Electronic nicotine delivery systems vaporize hydrophobic liquid containing nicotine, THC, flavorings, unregulated chemicals

Vapes/ENDS: clinical features

Acute airway resistance and inflammation, carcinogenic hydrocarbons

Cannabis/THC: mechanism of toxicity

THC causes sympathomimetic and anxiety/hallucination‑mediated cardiovascular stress

Cannabis/THC: clinical features

Hyperemesis syndrome

Cocaine: mechanism of toxicity

Sympathomimetic causing vasoconstriction, tachycardia, hypertension via beta‑adrenergic stimulation

Cocaine: clinical features

Hemorrhagic alveolitis (“crack lung”), pulmonary edema, pulmonary hypertension.

Cocaine: treatment

Avoid beta‑blockers in acute toxicity»they can lead to inc stim of alpha receptors and overall spike in HTN»Stroke

Heroin toxicity: clinical features

Obtundation → hypoventilation → hypercarbic respiratory failure