How frequently does one see resting tremor in drug-induced Parkinsonism?  

I have rarely seen resting tremors in drug-induced Parkinsonism. The exception is when the "inducing" drug is Depakote or Lithium. I have seen this numerous times. Often, the discontinuation of these medications (if possible) can result in resolution of the tremors and other Parkinsonian signs, howe...

Rest tremor is not uncommon in drug-induced Parkinsonism, I have seen it from dopamine receptor blocking "neuroleptics" and from VMAT inhibitors. This article cites that 30-50% of patients with DIP have rest tremors: Shin and Chung, PMID 22523509.