Adverse reactions observed in patients receiving tetracyclines include anorexia, nausea, vomiting, diarrhea, rash, photosensitivity, urticaria, and hemolytic anemia. (6) To report SUSPECTED ADVERSE REACTIONS, contact Mayne Pharma at 1-844-825-8500 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trial Experience The safety and efficacy of DORYX Tablets, 200 mg as a single daily dose was evaluated in a multicenter, randomized, double-blind, active-controlled study. DORYX Tablets, 200 mg was given orally once-a-day for 7 days and compared to doxycycline hyclate capsules 100 mg given orally twice daily for 7 days for the treatment of men and women with uncomplicated urogenital C. trachomatis infection. Adverse events in the Safety Population were reported by 99 (40.2%) subjects in the DORYX Tablets, 200 mg treatment group and 132 (53.2%) subjects in the doxycyclinehyclate capsules reference treatment group. Most AEs were mild in intensity. The most commonly reported adverse events in both treatment groups were nausea, vomiting, diarrhea, and bacterial vaginitis, Table 1. Table 1: Adverse Reactions Reported in Greater than or Equal to 2% of Subjects DORYX Tablets, 200 mg N = 246 Preferred Term n (%) Subjects with any AE 99 (40.2) Nausea 33 (13.4) Vomiting 20 (8.1) Headache 5 (2.0) Diarrhea 8 (3.3) Abdominal Pain Upper 5 (2.0) Vaginitis Bacterial 8 (3.3) Vulvovaginal Mycotic Infection 5 (2.0) Because clinical trials are conducted under prescribed conditions, adverse reaction rates observed in the clinical trial may not always reflect the rates observed in practice. 6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of doxycycline. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate a causal relationship to drug exposure. Due to oral doxycycline's virtually complete absorption, side effects to the lower bowel, particularly diarrhea, have been infrequent. The following adverse reactions have been observed in patients receiving tetracyclines: Gastrointestinal: Anorexia, nausea, vomiting, diarrhea, glossitis, dysphagia, enterocolitis, and inflammatory lesions (with monilial overgrowth) in the anogenital region. Hepatotoxicity has been reported. These reactions have been caused by both the oral and parenteral administration of tetracyclines. Esophagitis and esophageal ulcerations have been reported in patients receiving capsule and tablet forms of drugs in the tetracycline- class. Most of these patients took medications immediately before going to bed [see Dosage and Administration (2.1) ]. Skin: Maculopapular and erythematous rashes, Stevens-Johnson syndrome, toxic epidermal necrolysis, exfoliative dermatitis, and erythema multiforme have been reported. Photosensitivity is discussed above [see Warnings and Precautions (5.3) ]. Renal: Rise in BUN has been reported and is apparently dose-related [see Warnings and Precautions (5.7) ]. Hypersensitivity reactions: Urticaria, angioneurotic edema, anaphylaxis, anaphylactoid purpura, serum sickness, pericarditis, and exacerbation of systemic lupus erythematosus. Blood: Hemolytic anemia, thrombocytopenia, neutropenia, and eosinophilia have been reported. Intracranial Hypertension: Intracranial hypertension (IH, pseudotumor cerebri) has been associated with the use of tetracycline [see Warnings and Precautions (5.5) ] Thyroid Gland Changes: When given over prolonged periods, tetracyclines have been reported to produce brown-black microscopic discoloration of thyroid glands. No abnormalities of thyroid function are known to occur.