Method

Route

Time to reach Brain

Inhaling

Drug in vapor form is inhaled through mouth and lungs into circulatory system.

7 seconds

Snorting

Drug in powdered form is snorted into the nose. Some of the drug lands on the nasal mucous membranes, is absorbed by blood vessels, and enters the bloodstream.

4 minutes

Injection

Drug in liquid form directly enters the body through a needle. Injection may be intravenous or intramuscular (subcutaneous).

   Intravenous

   Intramuscular

20 seconds

4 minutes

Oral ingestion

Drug in solid or liquid form passes through esophagus and stomach and finally to the small intestines. It is absorbed by blood vessels in the intestines.

30 minutes

Other routes

Drugs can be absorbed through areas that contain mucous membranes. Drugs can be placed under the tongue, inserted anally and vaginally, and administered as eyedrops.

Variable

Information from: Hart & Ksir, 2014; Landry, 1994.