What is the most important precaution for a patient prescribed tetracycline?

The most important precaution for a patient prescribed tetracycline is the use of sunscreen or avoidance of sunlight. Tetracycline is known to increase sensitivity to sunlight, which can lead to a higher risk of sunburn or skin damage when exposed to ultraviolet (UV) rays. This phototoxicity is a significant concern, and patients are advised to take protective measures, such as using sunscreen with a high SPF, wearing protective clothing, and limiting sun exposure, especially during peak hours.

While avoiding dairy products is relevant due to the potential reduction in the absorption of tetracycline when taken with calcium-rich foods, it is not as immediately critical as the concern for sun exposure. Increased fluid intake is generally good practice for many medications, particularly those that could cause kidney issues, but it is not a specific requirement for tetracycline. Taking the medication with meals may help with gastrointestinal tolerance but does not address the key precaution regarding increased sensitivity to sunlight. Hence, the focus on sun protection highlights the unique side effect associated with tetracycline use.