According to the medical journal the Lancet (2007), heroin is the most deadly and addictive of the twenty most common recreational drugs. Even though heroin does not carry the allure of cocaine, heroin usage is still an international problem. An opiate drug extracted from the opium poppy, heroin is an extremely potent analgesic (NHS). Remarkably, the effects of heroin can remain for up to five hours, and a single use is enough to fuel a life-long addiction.
Heroin and the other opiates (morphine, codeine, etc.) when taken orally or inhaled must undergo first-pass metabolism, which decreases the potency of the drug (Sawynok, 1986). However, when heroin is injected it is able to by pass the blood-brain barrier as well as the fast-pass system. Once inside the brain, heroin breaks down into three different components, the quintessential and final form being morphine (Dubuc, 2002). Morphine, an μ-opioid agonist, binds to μ-opioid receptors present in the brain, spinal cord and gut. The binding of the morphine to these receptors creates the sedative, euphoric and pain-relieving effects. The pleasurable feelings produced the heroin are positively reinforcing because they activate the limbic system or pleasure centre of the brain.
Prior to heroin entering the system, inhibitory neurotransmitters (GABA) are active in the synapse (Dubuc, 2002). These inhibitory neurotransmitters inhibit dopamine from being released. Natural opiates (endorphins, enkephalins, etc.) block the release of neurotransmitters that inhibit dopamine release. As such, when the natural opiates attach to the opioid receptor dopamine floods into the synapses. Heroin mimics the natural opiates released by our system when morphine attaches to the opiate receptor. The release of dopamine causes an immediate sense of welling being or euphoria, sedation and pain-relief.
Just like with cocaine abuse the effects are not just limited to the brain. Addiction not only destroys relationships and financial security; overdose does not need to be the only cause of death.
Heroin was first synthesised by C.R. Adler Wright in 1874 when he added two acetyl groups to the morphine molecule (Sawynok, 1986). Morphine itself comes from latex harvested from green capsules of the opium poppy. The use of opium predates written history with evidence of the poppy found in Mesopotamia. Wright’s discovery of heroin, however, was largely ignored until it was accidentally re-synthesised by Felix Hoffman of what is now Bayer pharmaceutical company. Hoffman ironically was trying to synthesise codeine (a less addictive and less potent form of morphine), however, instead also produce an acetylated form of morphine otherwise known as heroin (Chemical Heritage Foundation, 2010).
The medical name for heroin is diacetylmorphine or morphine diacetate otherwise known as diamorphine. Today heroin is known by a variety of street names including H, horse, black tar, brown and smack.
As with all other drugs that work on the reward-system, overtime pleasure experienced by the excess release of dopamine diminishes. As a result, an addict must increase their dosage to experience the same high. It is often by addicts that no high ever measures up to the first one. Remarkably, this shows how quickly the drug effects our normal ability to feel pleasure and relief.
Physiological and psychological effects of addiction (Timberline Knolls Residential Treatment Center, 2013):
– Dry mouth
– Cycles of hyper alertness followed by extreme drowsiness
– Sudden behavioural changes
– Constricted pupils
– Shortness of breath
– A droopy appearance
Heroin Overdose and Treatment
Like all class A drugs, the risk of heroin overdose is common. As such it is important that these symptoms are recognised by medical professionals as well as anyone else witnessing any of the following (U.S. National Library of Medicine, 2013):
– Spasms of the stomach and/or intestinal tract
– Low blood pressure
– Weak pulse
– Dry mouth
– Extreme pupil constriction
– Tongue discolouration
– Slow, shallow or no breathing
– Bluish nails and lips
– Extreme drowsiness
– Muscle spasticity
Even if you are not medical professional, if you notice any of these symptoms you should call poison control.
Dubuc, Bruno. “THE BRAIN FROM TOP TO BOTTOM.” THE BRAIN FROM TOP TO BOTTOM. Douglas Hospital Research Centre, Sept. 2002. Web. 17 Nov. 2013.
“Felix Hoffmann.” Homepage of the Chemical Heritage Foundation. N.p., 2010. Web. 17 Nov. 2013.
“Heroin Addiction Symptoms and Effects.” Heroin Addiction. Timberline Knolls Residential Treatment Center, 2013. Web. 17 Nov. 2013.
“Heroin Overdose: MedlinePlus Medical Encyclopedia.” U.S National Library of Medicine. U.S. National Library of Medicine, 31 Oct. 2013. Web. 17 Nov. 2013.
Nutt, David, et al. “Development of a rational scale to assess the harm of drugs of potential misuse.” The Lancet 369.9566 (2007): 1047-1053.
Sawynok, Jana. “The therapeutic use of heroin: a review of the pharmacological literature.” Canadian journal of physiology and pharmacology64.1 (1986): 1-6.