Which of the following drugs is known to cause a myopic shift?

Topiramate is known to cause a myopic shift due to its effect on the ciliary body and vitreous humor in the eye. This anticonvulsant medication can lead to changes in the shape of the eye, specifically causing the eye to become more rounded, which increases its refractive power and results in nearsightedness. This myopic shift can occur shortly after initiating therapy with topiramate, making it a significant side effect that healthcare providers need to monitor in patients starting this medication.

The other options do not typically cause a myopic shift. Rifampin is primarily an antibiotic used in tuberculosis treatment and does not have a known effect on refractive changes in vision. Methotrexate, an antimetabolite used in cancer treatment and autoimmune diseases, has its own set of ocular side effects, but a myopic shift is not one of them. Digoxin, a medication used to treat heart conditions, can lead to various visual disturbances, but again, a myopic shift is not a common result of its use. Thus, topiramate stands out as the correct answer when considering drugs associated with myopic changes in vision.