The plan was to switch to Bactrim.
 the patient is not on antibiotics
(ROOT (S (NP (DT The) (NN plan)) (VP (VBD was) (S (VP (TO to) (VP (VB switch) (PP (TO to) (NP (NNP Bactrim))))))) (. .)))
(ROOT (S (NP (DT the) (NN patient)) (VP (VBZ is) (RB not) (PP (IN on) (NP (NNS antibiotics))))))
( ( The plan ) ( ( was ( to ( switch ( to Bactrim ) ) ) ) . ) )
( ( the patient ) ( ( is not ) ( on antibiotics ) ) )