What drug are you using and why?
There are no real blood thinning drugs (blood thinning would be achived by drinking more water for example).
The drugs out there to prevent blood clotting/thrombosis are either anticoagulants (direct like Heparin or indirect like Warfarin) or antiplatelet drugs (Aspirin or Clodpidogrel for example), there are other drugs but those are mostly used in an ambulance or hosptial
Now normally those drugs are used to prevent thrombosis after an operation or if you have a certain illness like angina pectoris or had a myocardial infarction. In those cases using stimulants like methamphetamine is a really bad idea