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Video transcript

Although there are surprisingly high number of ways of getting drugs into your body, called routes of entry, we're just going to talk about some of the most common. So one that might come to mind pretty easily when you think about, maybe hard-core drugs is injection, so we'll talk about that. The other main routes are oral entry and inhalation. Oral entry means that you swallow something, so that could be a pill or some alcohol. Either way you're eating or drinking it. You're ingesting it in some way, and this is one of the slowest routes of entry because it has to go through your gastrointestinal tract in order to get absorbed by your bloodstream, which can take about half an hour, give or take a few minutes. Inhalation, on the other hand, which is when you snort or smoke or breathe in the drugs is actually much faster because once you inhale it, it pretty much goes straight to your brain. It can be there within 10 seconds, and then you start feeling the effects. So this would be, a lot of times, tobacco or cocaine is often snorted. And finally the most direct route is injection. With injection, we're usually talking about intravenous injection, which means it goes right into a blood vein. This begins to take effect within seconds. Intravenous injection can be very dangerous because you're much more likely to inject bacteria or other unexpected toxins along with the drugs, especially if you're using unsterilized paraphernalia. So if someone else has used the needle before you, then this increases the likelihood you'll be exposed to something harmful, such as HIV. OK, so those are the three most common routes of entry and I'm just going to mention two more that are moderately common, transdermal and intramuscular. Transdermal entry means that the drug is absorbed through the skin. This is how patches like the nicotine patch, for example, works. The drug in the patch has to be pretty potent and it can be released into the bloodstream over several hours. Intramuscular entry means that a needle is stuck directly into the muscle, so before we talked about intravenous injection, this is intramuscular. Depending on the chemical properties of the drug, this method can deliver the drugs to your system very quickly or more gradually. One example of a really quick entry for intramuscular injection is when an EpiPen is administered to someone experiencing a severe allergic reaction. So when people have such a reaction, their airway start to close up, so they need to get a dose of epinephrine into their body to open their airways as quickly as possible. If you've ever seen or done this, the needle usually goes into a large muscle in your thigh because studies have shown that to have the most access points to blood vessels, you need to stick it in that particular muscle, so the epinephrine can take effect really quickly. Many vaccines are also administered intramuscularly which is why your arm gets sore after some shots, like the flu shot or something. Now I've been talking about how fast these different drugs take effect based on the route of entry which might be clearly relevant in the case of the EpiPen when you're trying to save someone's life. But another important element connected to the rate of absorption is the potential to produce dependence. People are more likely to become dependent on drugs that take effect more quickly. For example, injected drugs have higher addictive potential than pills.