Opioid

Scored poppy pod with the 'milk. This is used to make opium.

Raw opium

Opioids are substances that act on opioid receptors to produce morphine-like effects. Opioid receptors are widespread in the brain, and are also in the spinal cord and digestive tract.

Opioids are chemical substances that relieve pain. There are a wide range of natural and artificial opioids. They are used in hospitals to treat acute pain, as can occur after an operation. They can also be used to relieve pain, where treatment no longer makes sense, for example in certain cancer patients. Drugs that can relieve pain are broadly known as analgesics.

Certain opioids are used as anesthetics, as well as in emergency medicine and intensive care. There are cases which are difficult to manage with non-opioid analgesics.

Certain opioids have been used as illegal drugs. They can cause impairment if taken in large amounts. Most opioids are controlled substances, only available by prescription.

The term opiate is sometimes used as a synonym. Most often it is used to refer to opium alkaloids, and semi-synthetic opioids.

Natural opioids

Endogenous opioids

So called endogenous opioids, also called endorphins, are peptides produced by the human body. They are used to respond to stress, to suppress pain and hunger. They also interact with sex hormones and they can cause a state of Euphoria. Mammals produce them in the brain.

Opium alkaloids / Opiates

There are different alkaloids that naturally occur in opium. Opium is produced from Opium poppy. The most important ones are morphine, codeine and thebaine. Papaverine and noscapine also occur in opium, but the way they work is different. Most of the time, they are therefore not counted as opiates.

Semi-synthetic opioids

These are produced based on natural opioids, which are changed. Examples include heroin and oxycodone.

Fully synthetic opioids

Fully synthetic opioids are completely man made. They can be made from parts of the plant or latex or chemically. By definition they are synthetic chemicals not found in the plant in nature. An opium poppy does not contain any of the synthetic opioids, only opiates (non-synthetic) Examples are:

• Pethidine, sometimes given alongside morphine (an opiate) during labour
• Methadone
• Fentanyl, and alfentanyl, two examples of fentanyl analogues with more powerful but extremely short durations of action

Addiction to opioids

Drug tolerance to opioids and other narcotics can develop with long use. This means that higher doses will be needed to keep the same effect. It also means that the body will eventually learn to operate normally with that amount of medication. When the user tries to stop taking these pain killers, withdrawal symptoms appear. Withdrawal from opioids is not life-threatening, but it can be uncomfortable, so it is important to get medical supervision. These symptoms include restlessness, pain in the bones and muscles, insomnia, diarrhoea, vomiting and involuntary leg movements. However, the psychological symptoms, including cravings, depression, anxiety, and insomnia, are more likely to lead a person to relapse if they are not working with a doctor to safely detox.

If the addiction keeps on going, eventual permanent brain changes can appear, which eventually adapts to the drug's presence. Both prescription and recreational users of Opioids find that they will have to take increasingly larger doses of the drug to get the same effects, a process known as developing a tolerance. As users take greater and greater amounts of Opioids, they become progressively dependent on them. At this point, a full-blown addiction has developed. Even patients who experience chronic pain may be at risk for addiction, even though they are prescribed Opioids for treatment.

Overdose

Main article: Opioid overdose

See also: Naloxone

Opioid overdose happens when someone takes too much, they are switched from one of the opioids or opiates to another, or they are not used to taking them (called opioid naïve users). It can happen with all opiates, opioids, and semi-synthetic versions. Although there are comparisons between opioids (for example the Morphine-equivelant-dose scale), different opioids or opiates might be weaker than another or have different mechanisms, or others may be more dangerous than others. Overdose in hospitals are less common than street overdoses but the difference between forms is considered when using or prescribing opioids based on how used to opioids the patient is (how opioid-tolerant they are). This means that some opiates require a more opioid-tolerant patient, or that an opioid-tolerant patient might need a more powerful opiate. A street user is much less at risk from overdose by changing the drug used because there is less difference in their habitual use, or what drug they do take. A much greater risk in this group of people is tolerance build-up, which makes them need more of the drug to get the effect they want. This can lead to overdose. Rebound tolerance is a common reason people overdose, and this is when someone stops taking the drug for some time, so that their tolerance is gone by the time they do it again. Their tolerance is not at the same level so the same dose they used to take causes them to overdose.

The risk of overdose is lower when smoking if it is a smokable drug, like heroin. In this route of administration, the heroin is melted on tin foil and the fumes smoked. This form of drug-taking can be dangerous if the additives on the tin-foil are not burned away before smoking. What this means is, things on the tin-foil (like vegetable oil and other metals) release toxic fumes when burned. It is prevented by running a flame over the foil a few times before smoking. Some opioids come with anti-abuse mechanisms, such as tablets that cannot be crushed (OxyContin do this) or by mixing the opioid with Naloxone, so that it cannot be injected or does not work if it is. In addition to helping to prevent overdose (as injectable forms go straight into the bloodstream, and have a bigger effect) it also helps stop people from getting side effects such as collapsed veins or STIs (or diseases, like right side infective endocarditis).

Overdose is countered by Naloxone. There is no risk to using Naloxone. The effects (when the user has taken opiates) are negative as the good feeling of the drug, occupying (agonising) the opioid receptor, is replaced by the antagonistic receptor binding of the Naloxone. This replaces the effect of opioids, including the effects of overdose.

Naloxone can be given more than once, and sometimes needs to. Because it lasts about 30 minutes, if the effects last longer than that, or if a lot of opioids have been taken, then another dose might have to and can be given if they start to overdose again. There is no risk to using Naxolone and passing out is common in opioid overdose.

It can be given as a nasal spray, put into the nostril or used each time in one nostril and then the other. It is better to go to the other nostril between sprays. Naloxone is extremely cheap for the government to buy or pharmacy to make. Nalaxone (brand name Narcan) can be free in a lot of countries at GPs, drug treatment centers, or safe drug use buildings.

Symptoms

Symptoms of an opioid overdose include:

• Lips, nails, arms or legs with a blue tinge (or cyanosis of the skin)
• Falling asleep, or someone falling asleep, and it being hard to wake up (or if they do not react to shaking them or calling their name)
• Snoring

Naloxone does not cause harm if it is given when someone has not taken opioids or opiates, and it does not make people high. At the same time it can save life if an overdose is happening. The brand name for Naloxone is Narcan.

Related pages

• Narcan (brand name Naloxone)
• Cancer and fentanyl (often used in cancer pain management and palliative care)
• United states opioid epidemic
• Heroin (street name for diacetylmorphine)