How Heroin Works

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Heroin does originate from opium poppies, but not directly. As opium poppies flower, they fill with codeine- and morphine-rich sap. About one week later the sap has ripened and both the morphine and codeine can be extracted, usually by vertically cutting the sides of the seed pods. Typically, the seed pods are cut in late afternoon. This enables the sap to seep out overnight without drying or coagulating.

Personality Traits of Heroin Addicts

As the sap seeps out it comes in contact with oxygen and oxidizes turning a dark brown. The following morning the sap is harvested, then it’s cleaned and dried, and made into “Opium.” Most opium is about 10-14 percent morphine by weight. In places like Afghanistan and Mexico, where the drug trade thrives, morphine is mixed with acetic anhydride and boiled to make heroin.


What does heroin do when it enters the brain?

Regardless if a user sniffs heroin, smokes it or injects it, as heroin permeates the brain it attaches to tiny proteins atop nerve cells called receptors. Scientists have found three receptors that respond to heroin: mu (μ)kappa (κ) and delta (δ). These receptors are called opioid receptors and each type plays a different role. Since mu (μ)kappa (κ) and delta (δ) receptors are the first known opioid receptors, they are commonly referred to as the classical opioid receptors.

  1. mu (μ) opioid receptors (MOR) – the mu receptor is the main “heroin receptor.” Throughout the body these are the most abundant opioid receptors and they’re directly responsible for heroins’ pleasurable effects, acute pain relief, physical dependence and addiction, but also sedation, respiratory depression, slow heart rate, nausea and vomiting as well as reduced gastrointestinal motility.
  2. kappa (κ) opioid receptors (KOR) – the kappa receptor is responsible for heroin’s anxiolytic effects, trance-like states, physical dependence, and addiction, but also spinal analgesia, and dysphoria (in some).
  3. delta (δ) opioid receptors (DOR) – the delta receptor is responsible for heroin’s relief from persistent pain, reduced gastrointestinal motility and modulation of mood.


Actions of heroin

Heroin is an extraordinary drug because it binds to and activates μ-mu opioid receptors, which are the most prevalent and powerful opioid receptors in the brain and body, and the receptors most responsible for heroin’s effects.

  • Euphoria
  • Pain relief
  • Sedation
  • Respiratory depression
  • Constipation
  • Cough suppression


Heroin is a prodrug

What’s so ironic, is that heroin is really a “pro-drug.” This means that heroin doesn’t actually affect the brain. In fact, heroin doesn’t do anything to the brain.

6-monoacetylmorphine (6MAM)

By the time heroin gets into the brain it has already transformed into two different drugs:

  1. 6-monoacetylmorphine
  2. Morphine

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Active metabolites of Heroin

After heroin is administered it starts traveling through the circulatory system. As soon as heroin touches blood it begins spontaneously metabolizing into 6-MAM. Ironically, 6MAM also metabolizes into morphine, and morphine metabolizes into M6G, and M6G into another chemical and so on and so forth. These newly metabolized chemicals are classified as either active metabolites or inactive metabolites. Active metabolites produce drug effects and inactive metabolites do not. The top-two active metabolites of heroin are 6-monoacetylmorphine (6MAM) and morphine. Both 6MAM and Morphine mimic the brain’s naturally occurring opioid neurotransmitters – endorphins.



Neurotransmitters are chemicals within the nervous system that communicate information throughout our brain and body.  They send signals from one neuron to another neuron.  The brain uses neurotransmitters to tell your lungs to breathe, your heart to beat, and your stomach to digest.  They also affect your mood, focus, and motivation.

Endorphins are the body’s natural neurotransmitters and they typically reduce pain or modulate mood. All addictive drugs mimic the actions of some neurotransmitter; in the case of heroin that neurotransmitter is probably endorphin. Ironically, the word “endorphin” is short for endogenous morphine, which means morphine made from within the body.


Cause of opiate addiction

The likelihood that a drug will lead to addiction is linked to the speed with which that drug promotes dopamine, the intensity of dopamine effects and the reliability that dopamine effects will occur.

Opiates like heroin, morphine and oxycodone are fast acting, produce a lot of dopamine and work close to 100% of the time. That’s why these three opiates in particular have been linked to several opiate addiction epidemics. The U.S. is currently coming out of an oxycodone epidemic and we’re currently in another heroin epidemic. The only morphine epidemic began during the Civil War and was quickly supplanted by heroin at the beginning of the 20th century.


Heroin’s effects on the brain

Heroin’s effects not only depend upon which type of opioid receptor it activates, but also the area of the nervous system in which they’re activated. Three of the most affected areas are the limbic system, which is in the forebrain; the brainstem, which is the bottom-most portion of the brain; and the spinal cord, which is a thin tube of nerves that extends from the base of the brainstem downward. These areas are not the only places you’ll find opioid receptors, but they have the most opioid receptors, and also produce the greatest effects.



  • Limbic System – When heroin attaches to opioid receptors within the limbic system it creates feelings of pleasure, relaxation, and contentment.
  • Brainstem – Underneath the limbic system is the brainstem. It connects the forebrain with the spinal cord. When heroin attaches to opioid receptors in the brain stem it slows breathing, inhibits coughing, and reduces pain.
  • Spinal Cord – When heroin attaches to opioid receptors within the spinal cord it reduces pain.


How heroin increases pleasure?

What typically happens is that 6MAM and a little morphine bind to and activate more mukappa and delta opioid receptors than any naturally occurring event. Therefore, heroin use ultimately results in a massive amplification of dopamine activity, which produces intense pleasure.

The sequence of events, from heroin use to feeling good, is quite simple. Heroin turns into 6MAM and a little morphine via the blood and liver, respectively.  6MAM and a little morphine enter the brain and behave like neurotransmitters and activate opioid receptors in the Ventral Tegmental Area (VTA). These activated receptors inhibit the release of GABA. Less GABA stimulates the release of dopamine. Dopamine travels from the VTA to the nucleus accumbens (NAc). Dopamine in the NAc attach to Dopamine receptors (D2) and the post-synaptic response is pleasure.


Does Heroin Affect Sex Dive



Neurons and Interneurons

What we’re looking at here are neurons. Your average neuron consists of a cell body, an axon and dendrites. The left picture shows a GABA axon terminal on top and a Dopamine dendrite on the bottom. The right picture shows a Dopamine axon terminal on top and an unspecified dendrite on the bottom. The space in between one neuron and the other is called a synapse. That is where signals from one neuron pass to another. Since the two neurons are not connected, the neuron on the top must release chemicals (neurotransmitters) from little vesicles (the bubbles in the picture) into the synapse.

Opioid Interneuron

This is where it gets interesting. Neurotransmitters have one of two possible functions, either to excite or inhibit a response. GABA neurotransmitters are considered inhibitory neurotransmitters. So after GABA neurotransmitters cross the synapse, they bump into and activate GABA receptors on Dopamine dendrites. The GABA receptors then send inhibitory signals to the Dopamine nucleus – to not release Dopamine. However, when heroin is consumed, the opposite occurs. But why does that happen?

The answer is absolutely fascinating. Heroin enters the body and quickly turns into 6-monoacetylmorphine (6MAM) and a little Morphine. Both 6MAM and Morphine bump into and activate opioid receptors on GABA neurons. Both 6MAM and Morphine act like inhibitory neurotransmitters themselves and suppress GABA neurons, to greater or lessor degree depending upon dosage. 6MAM and Morphine slow the rate of GABA release, which results in disinhibition of Dopamine. The left image up top shows inadequate GABA unable to completely suppress the release of Dopamine. The right image up top shows Dopamine traveling down the axon and into a different synapse, where it bumps into Dopamine receptors of a third neuron and around and around the brain it goes.


How long does heroin work?

6MAM has a short elimination half-life, which ranges between 6-25 minutes. Therefore, approximately 30 minutes after heroin is administered, over half of 6MAM molecules will have metabolized into heroin’s second metabolite, that is to say morphine. Morphine’s half-life is around 2.5 – 5 hours. Heroin’s half-life is considered the total of these two, and that means heroin’s half-life is a little less than 3 – 5.5 hours. The drug-effects of heroin last between one and two half-lives or 3 – 11 hours. The mean average being 7 hours.

Morphine activates opioid receptors longer than all other active metabolites of heroin. Therefore, the lingering drug effects are more connected to morphine, while the acute drug effects are more connected to 6MAM, but they do overlap.


Heroin adverse reactions

The most common adverse effects associated with the heroin use include nausea and vomiting, sedation, itchiness, urinary retention and constipation. Serious adverse effects frequently reported with heroin use include: respiratory depression, hypotension and delirium.

  1. Heroin Overdose: Excessive heroin consumption may cause the brain to forget to breath. This may result in “hypoxia,” a medical condition in which there’s not enough oxygen in the blood to sustain life.
  2. Heroin Tolerance: Needing more heroin to get the same intensity of effect.
  3. Heroin Dependence: Chronic heroin use causes physical dependence, which means that you are susceptible to withdrawal symptoms when you stop.
  4. Heroin Addiction: Heroin use can also lead to addiction, which is a tenacious drive to get and use heroin despite negative consequences. It’s estimated that almost 1 in 4 (approx. 23%) new heroin users will become addicted.
  5. Viruses: If you consider intravenous heroin use, then there are other health risks, such as contracting HIV, Hepatitis C, and Hepatitis B.


How does heroin affect the Gastrointestinal Tract

Heroin depresses brain centers that control major muscle groups. These muscles groups respond by slowing down the rate and depth of respiration, inhibiting coughs, and slowing down gastrointestinal motility. Heroin works in the GI Tract by reducing peristalsis, decreasing gastrointestinal secretions and relaxing longitudinal muscle in the colon as well as simultaneously/increasing contractions of the anal, esophageal and other sphincter muscles.

1.Heroin works by inhibiting lower esophageal sphincter relaxation, which causes abdominal cramping.

2. Heroin works by contracting the gallbladder, which delays gastric emptying, and that can result in abdominal discomfort.

3. Heroin works by increasing acid release and delaying gastric emptying of the stomach, which results in nausea, vomiting and abdominal cramping.

4. Heroin works by slowing transit time of food, which results in constipation, bloating and cramping.

5. Heroin works by increasing anal sphincter tone (contracts sphincter), which results in constipation.


Treatment for heroin dependence

The following treatment options are typical heroin addiction recovery strategies.

  • Heroin Detox: Detox generally lasts about a week and includes medications like Suboxone that suppress withdrawal symptoms
  • Primary Care: 30-days or less residential treatment that generally combines behavioral and cognitive therapy.
  • Long-term Care: 31-days or longer residential or outpatient treatment services that generally combines treatment and recovery planning.


Heroin is a Narcotic

Heroin is a narcotic. A narcotic is a drug that produces narcosis. Narcosis means it makes you sleepy. Depending upon how much heroin you take, determines how much of a narcotic effect will occur. There are other factors as well, such as how long you’ve been using heroin, i.e. tolerance, and how you administer it. In general, heroin is taken in large doses, but regardless how much you take and how long you’ve been taking it, if it’s injected, it acts faster and more intensely.

The euphoric, analgesic, sedative and respiratory effects of heroin are well known. However, sedation and respiratory depression are two of the most serious problems, which is why heroin is illegal. There is another factor that’s often overlooked, that heroin kills people, and not just by overdose. Some people fall down and hit their head, others crash into pedestrians crossing the street.