Well, of course, they enter straight into the blood stream. And reach the brain directly. Ding!
If you inhale it, before it reaches the brain, it has to get into the blood first. And then, it has to go to the brain. So obviously drugs travel faster to brain when injected compared to when inhaled.
Let me elaborate this to you, who have forgotten their basics in biology. Please look at this picture:
When you inject a drug, let us say heroin, you send it straight into a vein, say in the arm. Now the chemical travels along the vein. Well, blood travels a bit slower in veins towards the heart compared to arteries, where blood travels faster away from the heart.
This vein finally joins the big vein called superior vena cava, which goes to the heart. That is to the right upper chamber of the heart called right atrium. From there it goes to the lower chamber, the right ventricle, and then through pulmonary artery to the lungs, for oxygenation.
The little heroin you injected now has to return to the heart, via pulmonary vein, this time to the upper chamber in the left side, left atrium. Then it has to go to the left ventricle and then it enters the aorta, the biggest artery in the body taking blood away from the heart. This gives branches that go to brain. So this is how heroin enters the brain after injecting a drug into a vein in the arm.
Now, let us look at what happens to heroin inhaled through the nose. This goes to the lungs, which easily allow even big molecules to cross and enter into the blood stream. Now the heroin in the blood, has to go to the heart via pulmonary vein to the left atrium, then to left ventricle, and onwards to the brain through the aorta. So, there you have it…
Hang on, it looks like inhalation is faster.
It must be much faster than injecting to a vein in the arm. Or to any vein in the body you can reach. So then, what have we been believing so far?
We all thought that injecting a drug gives a faster kick compared to inhalation. Well, the users say so. They DO seem to immediately feel the effect. Some can’t even pull the needle out, before they feel the effect. So, have they all been lying…? Or what?
Let us find the answer to that question in my next post…