If you look up the drug again but select the "For Professionals" tab, it gives you more in depth information. I realize that you are not a clinician but it could help. I know that since it relaxes muscles and relieves blood pressure, I would say that it is distributed into blood vessels and tissue. The document doesn't say what exact tissue which leads me to believe plasma concentration levels are universally distributed in muscle tissue throughout the body. To avoid paying a co-pay to see your doctor, any retail pharmacist can also answer your question better.