Phototoxic reactions are dose-related sunburn-like reactions that can occur with sufficient light exposure and a high enough dose of medication. Radiation in the UVA range causes most drug-related phototoxic reactions. Sunscreen can help protect skin but does not completely prevent skin damage from sunlight. Apply sunscreen to all exposed areas 30 minutes before sun exposure. Reapply 15–30 minutes later. To get the full effect of the sun protection factor (SPF), sunscreen must be applied correctly and in the correct quantity; approximately 30 mL to cover the entire body. Speak to your pharmacist to find out if your medications can cause Phototoxic reactions.