Overview

Doryx is the brand name of a time-released tetracycline antibiotic called doxycycline, prescribed for treating acne. The time-release action means Doryx is less likely to cause certain side effects associated with the less expensive generic version of doxycycline. Doctors prescribe Doryx because of its effectiveness in treating severe acne and acne that has not responded to topical therapy.

Function

Doryx reduces bacterial colonies that cause acne and also has anti-inflammatory properties. Doxycycline shows "very good" efficacy in acne reduction, as noted by a review of antibiotic acne therapies published in the November-December 2004 issue of the European Journal of Dermatology.

Combination Treatment

Physicians usually prescribe Doryx as a combination treatment with a topical retinoid medication, a type of vitamin A that reduces acne. Combining tetracycline with a topical retinoid is significantly more effective and works faster than using the antibiotic on its own, according to the European Journal of Dermatology study. After initial treatment, maintenance therapy also is significantly better when combining doxycycline with a retinoid, according to a study published in the May 2006 issue of Archives of Dermatology.

Time Frame

The patient typically begins with an initial Doryx dosage of 200 mg the first day, as explained by Physicians' Desktop Reference, taken in two separate doses. The dosage then becomes 100 mg once per day for the rest of treatment. Individuals usually must take Doryx for at least two weeks before beneficial results occur. The medication is not effective for everyone.

Doryx Advantages

Time-released Doryx has advantages over the generic form of doxycycline. Patients are less likely to accidentally miss a dose since they only take Doryx once a day. The time-release action also stops the tablets from working until they reach the small intestine, reducing or preventing stomach upset that sometimes occurs with doxycycline.

Considerations

Iron supplements and milk can reduce the effectiveness of Doryx. Additionally, Doryx can reduce the effectiveness of other drugs, including antacids, birth control pills and anti-coagulants, as well as vitamin supplements. Doryx also causes sensitivity to ultraviolet light. Like other antibiotics, Doryx kills friendly intestinal bacteria, which can lead to severe colitis.