1. causing toxic or harmful effects when exposed to light, especially ultraviolet radiation
Usage: commonly used in medical and pharmaceutical contexts; often describes substances, drugs, or chemicals

Examples

• Some antibiotics are phototoxic and can cause severe skin reactions when patients are exposed to sunlight.
• The dermatologist warned that certain essential oils are phototoxic and should not be applied before sun exposure.
• Phototoxic reactions occur when a chemical compound absorbs light energy and damages skin cells.
• Patients taking phototoxic medications are advised to use high-SPF sunscreen and avoid prolonged sun exposure.
• The phototoxic properties of the drug were discovered during clinical trials.