• Results of blood chemistry studies using an automated multiple analysis system and blood cell counts for 325 patients receiving long-term low-dosage tetracycline hydrochloride therapy continuously for three years or longer revealed minimal changes in all but one patient. This patient developed a transient hyperbilirubinemia with mild jaundice while taking 500 mg of tetracycline daily.
(Arch Dermatol 112:1603-1605, 1976)
Sauer GC. Safety of Long-Term Tetracycline Therapy for Acne. Arch Dermatol. 1976;112(11):1603-1605. doi:10.1001/archderm.1976.01630350071017