NIDA for Teens: The Science Behind Drug Abuse
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Drugs & Health Blog

Real Teens Ask about Effects of Heroin

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Sara Bellum

At NIDA’s last Chat Day, we got this question from a high school student:

”Why do people scratch a lot when they are high on heroin?"

A NIDA scientist responded that he had done years of research on this topic. He explained: “Heroin activates connections in the brain called opioid receptors. These receptors then activate fibers that transmit itch information (aka ‘pruritus’) to the brain. Thus, heroin users feel itchy. Good question.”

But before heroin can activate opioid receptors, it has to enter the blood stream and reach the brain. So how does this happen?

People usually inject heroin into their blood stream with a syringe. Soon afterwards, the heroin crosses the “blood-brain barrier”—a protective membrane that separates circulating blood from brain fluid in the central nervous system. Once in the brain, heroin is converted to a chemical called morphine and binds rapidly to the opioid receptors already mentioned. These receptors recognize chemicals affecting pain, like morphine.

Various drugs names.

Heroin users typically report feeling a surge of pleasure, or a “rush,” which makes sense because heroin enters the brain so rapidly. This quality also makes it extremely addictive. Along with the rush usually comes a warm flushing of the skin, dry mouth, and a heavy feeling in the arms and legs, which may be accompanied by nausea, vomiting, and, of course, severe itching. Also, since heroin is a depressant, it clouds your thinking and can slow—or even stop—breathing.

Because heroin is mostly sold on the street, users can’t be sure of the purity (or strength) of the drug they’re taking. Also, because it’s so addictive, they may crave bigger and bigger amounts of the drug to get the same rush they got the first time—which often leads to overdose and death.

Comments posted to the Drugs & Health Blog are from the general public and may contain inaccurate information. They do not represent the views of NIDA or any other federal government entity.


Once again, delivering great information. I always noticed the "itch" when in contact with addicts, but never knew the science behind it. Thanks for sharing!

I really do not like heroin
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Heroin actually has NO medicinal purpose. Which is why it's not used for any format of treatment. Instead things like morphine, oxycontin, or percocets are used for various treatments.
actually it isnt used due to the fact that once introduced into the body it is converted to morphine which we all know we already have also its addictive properties

what conditions are this drug used to treat

@bubbles According to Wikipedia, the chemical substance of heroin (diacetylmorphine) has also been used for pain management in some countries and as a maintenance drug to treat people addicted to opiates. opiate addicts. Neither of these treatments using heroin occurs in the United States.

why do people do drugs it is ignorint:(

Why do people have sex outside wedlock? Why do some folks drink? Why do we endulge ourselves with money, cars, houses, etc...? In my experiences, I've seen people trying to fill holes in their lives...people have affairs because some things are missing or misunderstood. Some drink and/or do drugs because of a tradgic loss of some sort. That's what I call holes...Those holes can be very deep, for example, a victim or abuse, be it sexual or physical. Please, don't judge these folks who are experiencing these things...after all, who are they to judge YOU, right? As the bible states, "Those without sin throw the first stone." I know it's hard if not close to impossible to understand why but it all basically falls under one little word...are you ready?...wait for it...selfishness. Every body wants to feel important, significant, wanted and loved. Truth is they are!! It's just that we want to trust in the things of this world but the thing is the things in this world break, rust or get old and when(not if)we get a bad deal disappointment sets in then we fold like a lawnchair. I believe in God and His son Jesus. (Yes, a "Jesus freak".) If it wasn't for that relationship with him 26 years ago I probably would've ended up in jail or dead. Anyway my point is that I gave up on the things of this world and trusted in the Truth. If nobody else cared, He will! Jesus filled those holes and made me significant, wanted, important and loved. No more holes hence no more drugs:)
This is so true. Even though all of this is anonymous. It really is making me think more about my decisions.
Im glad you came to find God, and may he continue to guide you through life
hey dude
Amen to that brother! Your message on here was powerful keep spreading the word!
Amen thanks for sharing
Good job Sir. It makes sense the way you put it.
John 3: 16revelation 21;4 psalms 37:11
You say drug users are "ignorint" and yet you're the one who can't spell IGNORANT. Walk a mile in someone's shoes before you judge.
I think the word you were searching for is "ignorant." Kind of ironic that you misspelled that, wouldn't you agree? By the way, I think there's a pretty good chance that most users have prior knowledge of what risks are involved; this is not some social/party drug that people just waltz casually into. Poor choice of words..

this was really interesting and i started to ich a little

do you really have to ask why? use your common sense. why do you fun things? because they are fun and you like the feeling. Thats how it is with people trying drugs. They like the feeling after trying one so they try another.

The first time I tried it was because my new boyfriend took it. I wanted to know what all the fuss was about, and when he offered me it, I said yes. I didn't know exactly what it was, but I took it anyway because I didn't want to come across as naive. One time, and I was hooked. I'm still hooked now, sitting smoking some now actually. The pain and depression I get when I'm off it is almost too much to handle. I hate this town, I hate the people and I hate my job. I hate heroin, most of all. I hate the noise of tin foil rustling because it makes me crave it, so I refuse to have any in the house when I'm clean. When I'm out of town, I'm fine. Very few/no withdrawals. Not until right before I'm due to come back. It's so easy to get hold of here. Easier than getting dope anyway. I have to get out of here. I need to go somewhere I don't know anyone, or more importantly, doesn't know ME. I live in a small, sh*t town full of judgemental a-holes. I'm an addict, so I MUST be horrible and a thief. Never stolen a thing in my life. We're all tarred with the same brush, but we're PEOPLE. Just in need of a little help. God knows I need help. I can't tell anyone, it'll tear my family apart again. I can't go to the doctor, people will see me and they'll talk, and my family will find out. They think I've been clean for nearly 6 years, when in truth, it's more like 2 all put together. Take it from me, drugs are sh*t. They ruin lives. I know this, and yet I'm still doing it. If you haven't touched it already, don't. It's not fun, it's not "cool" and it won't make anyone impressed.

Hey Amy, sorry to hear you're going through this. You may be able to find help using one of these free, confidential services from SAMHSA: They have a treatment referral helpline if you need help overcoming addiction, and the Suicide Prevention Lifeline is open 24 hours with people available if you want help working through problems or if you just want to talk.

What are a few long term effects of heroin?

@Stopheroin Good question. Regular heroin use can lead to a physical dependency. Over time, however, your body develops a tolerance, and users do not feel the same "high" once the brain and body become more accustomed to it, so you need more of the drug to get the same feeling. Other effects can be very serious - especially if you inject the heroin. These include: collapsed veins, bacterial infections, liver or kidney disease, lung problems (like pneumonia and tuberculosis), arthritis, and infectious diseases (like HIV/AIDS and hepatitis B and C). For more information on what heroin can do in the longer term, you may want to check out NIDA's InfoFacts on heroin: or the NIDA Research Report on Heroin:

heroin can cause alot of disease so dont do it


long term affacts are like liver disease and i think aids

You can only get aids if you share needles with someone who has it. You can smoke with people that have aids and not get it and smoke/slam by yourself without getting aids. I used to shoot drugs and I didn't get any diseas because I used a new needle every time.

and lung disease

why are people crazy enough to take drugs?

thanks for post.i allways suggest to everyone not to take Heroin.

drugs are a dumb thing to do

never do drugs they will mess with your head

this causes so many problems with stupidity, i mean why would u use such a drug that can cause death and mess u up and not only u but your family aswell

Most people start doing it because they r depressed and don't care.

this causes so many problems with stupidity, i mean why would u use such a drug that can cause death and mess u up and not only u but your family aswell

I think people are just really depressed and they stop caring about a lot so they turn to drugs.

@Nodrugs people are sometimes depressed or unhappy with their lives so they try new things that they think will make them feel better but in the long run it does not help them at all and they are actually made worse... lots of people have different reasons why they choose to do drugs. Although i think that people who do heroin they should know the side affects.

I also think they feel like they have the need to use it to fit in, they even have the need to fit in. They want attention, in other words, they want other's pity and they end up psychologically addicted. Getting addicted to drugs is an awful habit. I feel bad for the people who got themselves into the spiral of drug abuse. I am glad I am not.

Heroin gives you a "rush", similar to a roller coaster. That sounds like a good thing until the the "rush" doesn't come as easily as it did the first time. The "rush" only occurs for a second, then it leaves and you're left depressed, itchy, and longing for the drug. This drug can easily stop your breathing. If you're looking for a 'rush", look for a natural way to get that feeling. Go on a roller coaster or do something you enjoy. Don't use Heroine to find happiness because soon, that feeling will turn to depression. Roller coasters don't give you a short-term "rush" then leave sadness in its place.

I don't know where you read your information...heroin is the complete opposite of an "upper" there is no rush. I from personal experience of being a user at one point of my life, I can explain exactly how it is. There is NO intense rush at all after injecting it. It makes you feel as if you put on a warm cushioned helmet- just immediate sensation of being warm and numb- it IS a pain killer in the first place (depending on the quality of the heroin, you may even get hot and take your clothes off to feel comfortable) and your eyes feel dazed. Heroin slows your heart rate and breathing, but it's not very noticeable. Though, this is how people'll find anyone who fell victim to ODing with their body and lips blue from suffocating. There is also definitely NO depressing feeling after using it. The "session" is a very relaxed and sleepy feeling. It's very common for the user to "nod off"- where you literally cannot keep your eyes from closing (the exact way when you're so so so tired) and bob your head up and down for abit struggling to keep up. The only way you feel bad from heroin is when you're withdrawing. Heroin is a physically addicting substance more than it is mentally. After doing it for even a short time and then suddenly not having it, within 24 hours you feel awful. For 4-8 days depending on how heavy of a user you are, your nose runs, eyes water, you're constantly getting cold sweats and shivering with goose bumps everywhere, you cannot sleep for the life of you, your body and every muscle in your body just seems to ache- it's like an extremely bad cold. If you're a heavy user, you'll throw up and just look zombified. Everything you do from brushing your teeth to just standing upright for awhile takes an effort. This is "dope sick". Anyways, I can proudly say I been sober for almost 6 months after being a user for aprox 4 months. Don't ever try it, don't ever say "i'll do it once" because you'll likely do it again especially that you then know how to do it. I didn't do it nearly as long as the strung out heroin addicts- but withdrawing is still awful and not worth it.

The effects of heroin on the brain are scary... I just don't understand why people would choose to mess up their lives and the lives of others by taking it. You might think "I'm just going to do it once and then never again," But thats what they all say. Once the drug enters your limbic system and releases dopamine, you won't stop taking it and your whole life will go down the drain. DRUGS R BAD 4 U!!!!!!!!!!!!!!!!!!!!!!!

I find it very interesting that heroin users have the urge to itch their heads when they use heroin. I would never have guessed how that would happen. I wonder, since it turns into morphine when it's in the brain, if heroin users feel less pain? These questions could be answered if I search a bit more on this website.

My bfs a heroin addict and I'm anti drugs, I also wonderd if he couldn't feel pain because of it so I nipped him, turns out theyfeel pain, but not as sore as it would have been and their reaction time slows down.

The itching. To watch is strange.

not cool
Opiates cause itching by releasing histamines, which is the same compound in your body that is released when you are having an allergic reaction. To counteract the itch, many addicts take Benadryl with their fix - which enhances the high, due to it's sedative effects.
Why is heroine so good?

Hi Jeffery.  Heroin is a drug with powerful pain relieving properties.  It also gives the user a feeling of intense pleasure and well-being.  However, heroin is dangerous.  It can make you feel sick, slow or stop your breathing, and even put you in a coma.  Read Drug Facts: Heroin to learn more.

Why do your eyes turn white when you everdose

We are not sure what phenomena you are referencing. There is a typical look portrayed in movies and on TV showing people who have died from an overdose---showing their eyes rolled upwards, making their eyes look white. This, however, is not always the way a person would look after overdosing. In addition, an overdose causes the pupils to constrict and possibly look abnormal, but the eye color would remain. How a person would look upon overdosing also depends on other factors that may have contributed to their death, including the use of other drugs.


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