Trigger Point Injections vs. Dry Needling

Has anyone heard if Trigger Point Injections and Dry Needling are more or less effective for trigger point outcomes and patient pain relief?
With Trigger point injections certain medications are given via IM into the trigger point and "deactivate" that taut band of muscle contraction whereas dry needling involves manipulating the needle repeatedly but with out the administration of any medicine.
Any information would be great