Take this medication by mouth as directed by your doctor, usually 2 or 4 times daily. Tetracycline works best when taken on an empty stomach 1 hour before or 2 hours after meals. If stomach upset occurs, ask your doctor if you can take this medication with food. Take each dose with a full glass of water (8 ounces or 240 milliliters) unless your doctor directs you otherwise. Do not lie down for at least 10 minutes after taking this medication. For this reason, do not take it right before bedtime.

Take this medication 2 to 3 hours before or after taking any products containing magnesium, aluminum, or calcium. Some examples include antacids, quinapril, certain forms of didanosine (chewable/dispersible buffered tablets or pediatric oral solution), vitamins/minerals, and sucralfate. Follow the same instructions with dairy products (such as milk, yogurt), calcium-enriched juice, bismuth subsalicylate, iron, and zinc. These products bind with tetracycline, preventing its full absorption.

The dosage is based on your medical condition and response to treatment. For use in children older than 8 years of age, the dosage is also based on weight.

For the best effect, take this antibiotic at evenly spaced times. To help you remember, take this medication at the same time(s) every day.

Continue to take this medication until the full prescribed amount is finished even if symptoms disappear after a few days. Stopping the medication too early may result in a return of the infection.

Tell your doctor if your condition lasts or gets worse.