A patient wears SRx +1.00 DS -2.00 DC x 180 with a +3.00 D round 28 bifocal segment. If the top of the segment is 5 mm below the distance optical center, and the patient reads 5 mm below the top of the segment, calculate the image displacement due to the distance prescription.

All of the following oral antibiotics may exacerbate the effects of warfarin EXCEPT: