Routes of drug entry | Processing the Environment | MCAT | Khan Academy

Routes of drug entry | Processing the Environment | MCAT | Khan Academy


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.

6 comments

  1. I think smoking and snorting shouldn't be included in the same category as they have very different mechanisms and thus very different effects. You should differentiate between insuflation and smoking. It most certainly does not take 10 seconds for an insufflated drug to reach the brain. Where smoking a drug causes a very fast onset.

  2. Smoking and snorting have two different mechanisms of entry ..also inhalation is fastest for most substances versus injection. This video and lecturer needs to be fact checked.

  3. Thanks for the efforts! I also did talk about the different Routes of drug Administration at the end of my latest video (Polymorphs Solubility) in my channel. I hope it will be of extra help to viewers!!

  4. Thanks for the efforts! I also did talk about the different Routes of drug Administration at the end of my latest video (Polymorphs Solubility) in my channel. I hope it will be of extra help to viewers!!

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