Oral administration of a solid dosage form of the present invention comprising an effective amount of rifabutin, an effective amount of clarithromycin, an effective amount of clofazimine, and an effective amount of an absorption enhancer, is used to treat a subject suffering from, or susceptible to, Mycobacterium avium subspecies paratuberculosis infection. In an embodiment, the solid dosage form is sufficiently designed to result in a reduction in the increased metabolism of clarithromycin caused by rifabutin. In an embodiment, the solid dosage form is sufficiently designed to result in a reduction in the metabolism of rifabutin caused by clarithromycin. In an embodiment, the solid dosage form is sufficiently designed to result in a reduction in risk of a subject developing leucopenia or uveitis as a result of rifabutin.
