Category Archives: Pharmacology

Heroin and the Brain


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.

The High

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.

Physiological Symptoms

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 3Heroin 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).

heroin 4The 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.

Heroin Addiction

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

– Disorientation

– Sudden behavioural changes

– Constricted pupils

– Shortness of breath

– A droopy appearance

Heroin Overdose and Treatment

heroin 5Like 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

– Delirium

– Disorientation

– Constipation

– Extreme drowsiness

– Muscle spasticity

– Coma

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.


Elucidating Experiments: Are Magic Mushrooms Beneficial

shroomA 2011 study conducted by John Hopkins University School of Medicine has found that as little as a single dose of magic mushrooms can increase the ‘openness’ trait. According to study leader Roland R. Griffiths a single dose of psilocybin, the activate and hallucinogenic component of magic mushrooms, is enough to bring about a significant change in personality.

shroom2Of the 51 participants that took part in the study, 60% reported lasting changes a year after the study was conducted. The longevity of these changes suggests that personality changes are most likely permanent. This is even more substantial considering that the trait for openness actually declines over time.

Openness is one of five personality traits measured by a ‘scientifically validated personality inventory,’ which also includes neuroticism, extroversion, agreeableness and conscientiousness and are considered to be the ‘makeup’ of our personality. Openness includes traits that are related to abstract thought, aesthetics, feelings, and imagination; furthermore, the changes in openness were greater than personality changes in healthy individuals observed over decades. Most commonly, personality changes are not even significant over the age of 30.

Griffiths, the leader of study, believes that “psilocybin may have therapeutic uses” as he is currently studying how hallucinogens can be beneficial in dealing with depression and anxiety common in cancer patients and addicts.


Griffith, Roland R., Johnson W. Matthew, and Katherine A. MacLean. “SINGLE DOSE OF HALLUCINOGEN MAY CREATE LASTING PERSONALITY CHANGE.” Comp. Stephanie Desmon. John Hopkins Medicine (2011): n. pag. 29 Sept. 2011. Web.

Cocaine and the Brain


As part of a new series on drugs that affect the nervous system, I thought I would begin with cocaine. Unlike many other drugs for some reason cocaine is associated with the rich, famous and successful rather than with troubled teenagers and the homeless. Despite its allure cocaine is a highly additive and highly deadly substance. As a powerful stimulant the powerful high can last anywhere from 15-30  minutes up to an hour. Surprisingly, at least to me, approximately 14% of the American population has tried cocaine (WedMD, 2013) with the largest demographic being males between the age of 18 to 25.


Cocaine like most other recreational drugs affects the brain; if it didn’t there would not be much allure to them really. Most people are after all drawn to drugs because of the escape they offer. Unfortunately, no drugs that play with the mind are to be trusted. As a class A drug, the side effects more than out weighs the highs. Cocaine affects the the neurochemical pathways by blocking the re-uptake of neurotransmitters such as norepinephrine, serotonin, and dopamine.


As it blocks these three common neurotransmitters it is called a triple re-uptake inhibitor. Drugs that increase the concentration of these specific neurotransmitters are said to be positively reinforcing meaning they create a pleasurably feeling that can become addicting. Addictions such as sex, gambling, eating, etc. can become addictive because they also produce pleasurable feelings that can be self-reinforcing.

The High 

In cocaine users these highs are described as euphoric with accompanying feelings of supremacy, positive mood and also an increase in energy and alertness. You can see why famous detective Sherlock Holmes may have been drawn to such a drug. However, sometimes the high can result in increased levels of anxiety, restlessness, paranoia and irritability. Such symptoms illustrate the dangers of playing with our neurochemical balance; we cannot be certain the pathways we affect are going to result in positive feelings. People with a family history of mental illness are increasingly vulnerable to the effects of cocaine use because such a major flux in their brain chemistry can trigger the onset of disorders ranging from bipolar disorder to schizophrenia.

Physiological Symptoms 


The dangers of cocaine abuse are not just limited to the brain. Travelling through the blood, cocaine can have devastating effects of the heart, the kidneys, the respiratory system, the gastrointestinal tract and even sexual function. You can read more about these effects on WedMD.


Extracted from the coca leaf, cocaine or benzoylmethylecgonine is a crystalline tropane alkaloid (-ine suffix) meaning that it has a crystal-like and nitrogen-based structure that occurs naturally. The coca leaf is mostly found and cultivated in the Andes of South America. From the coca extract the two major forms of cocaine are crack cocaine and powdered cocaine.


Crack cocaine is the free-base from of the drug meaning it still in its crystalline structure making it possible to be melted down to be smoked.  Powdered cocaine can be dissolved into water or inhaled.

A major danger with cocaine is that it contains a lipophilic group, a hydrophilic group, and an aliphatic group. Meaning it can pass through polar and non-polar membranes, specifically the blood-brain barrier.

Cocaine Addiction 

Over time the reward-system established by frequent cocaine abuse causes damage to the dopamine pathway. This damage means that the pleasure experienced becomes diminished and for the person to experience the same high they must now increase their dosage. Increased cocaine dosage obviously increases the physiological and psychological effects of cocaine addiction.


Physiological and psychological effects of addiction:

  1. Mood swings
  2. High blood pressure
  3. Panic attacks
  4. Cognitive impairment
  5. Changes in personality
  6. Psychosis: including tactile hallucinations (“coke bugs” or formication)
  7. Paranoia
  8. Insomnia
  9. Tachycardia (increased heart rate)

Symptoms of cocaine withdrawal include:

  1. Depression
  2. Paranoia
  3. Exhaustion
  4. Mood swings
  5. Itching
  6. Anxiety
  7. Insomnia
  8. Craving

Cocaine Overdose and Treatment 

Due to the serious nature of the effects of cocaine abuse, cocaine overdose is common amongst users. The most common cause of death due to overdose is tachycardia, and is a result of the body weakening due to the drug rather than an a lethal dosage. As such, cocaine related deaths are frequently accidental. The increased heart rate elevates blood pressure to the point of  respiratory failure, stroke, cerebral hemorrhage, or heart-failure.


Unfortunately, even when a person overdosing is brought to an emergency room not much can be done except treat the symptoms. As of right now there is no antidote for cocaine. However, it is still important that these symptoms are treated as it may be able to prevent the above listed causes of cocaine-related deaths.

The symptoms to look for include:

  1. Nausea
  2. Chest pain
  3. Increased heart rate
  4. Fever
  5. Tremors
  6. Vomiting
  7. Seizures
  8. Paranoia
  9. Hallucinations
  10. Delirium


Thank you for reading! Please comment with any drug you would like to learn about next.


“Cocaine Overdose Symptoms and Treatment.” Cocaine Overdose Symptoms, Signs, and Treatment. Project Know, 2013. Web. 16 Aug. 2013. <;.

“Cocaine Use and Its Effects.” WebMD. WebMD, n.d. Web. 16 Aug. 2013. <;.

“DrugFacts: Cocaine.” National Institute on Drug Abuse. NIH…Turning Discovery Into Health®, Apr. 2013. Web. 16 Aug. 2013. <;