Codeine is commonly used to treat mild to moderate pain and is described as a ‘weak opioid’. Low strength codeine can be bought over the counter in the form of co-codamol. Higher strength codeine is legally controlled, and it is against the law to possess it without a prescription.
Some of us get a euphoric or relaxing effect from taking codeine, which can lead to misuse and addiction. Long term codeine use can damage parts of the body and brain and actually increase pain sensitivity, the opposite of its intended use. Overdoses of any opioids can be fatal.
Morphine is commonly used to treat severe pain and is a ‘strong opioid’ available only on prescription. Dependency can develop quickly, hence the need to prescribe cautiously and monitor for dependence, tolerance and addiction.
For some of us, a sensation of deep relaxation and feelings of extreme well-being may be seen with morphine use. Long term use of morphine, like codeine, can lead to more severe physical and mental health impairment, more severe withdrawal and life-threatening in an overdose.
Oxycodone is now the most misused prescription drug in the USA where it is often referred to as ‘hillbilly heroin’ and it is rapidly gaining in popularity in the UK as well.
Oxycodone is a synthetic form of morphine; it is roughly double the strength of standard morphine, which is why it is so dangerous.
Oxycodone creates similar effects to heroin, meaning that its misuse to escape physical and mental health ‘pain’ is high. It can sometimes be describe as being wrapped in cotton wool.
Tramadol is a commonly prescribed opioid used to treat moderate to severe pain. It was initially thought to have a lower potential for misuse than morphine or oxycodone, but experience over the years has shown that it does have significant potential for misuse. Some time after its launch, it was therefore reclassified by the UK government to a legally controlled drug. In some people, it can cause feelings of well-being and relaxation, as well as euphoria if used in higher doses. Stopping Tramadol suddenly can cause withdrawal symptoms for longer than other opioids, and occasionally it can cause death in a similar way to heroin
Diamorphine is a class A drug and is the semi-synthetic opioid, similar to heroin but medically purified. Heroin is a crude form of heroin. It is 2-3 times stronger than morphine and is used in healthcare for severe pain. It is given by injection only, either into a vein or under the skin. If misused illicitly, it is very addictive and as addictive as heroin, but heroin misuse is far more common than diamorphine misuse.
Fentanyl is a strong synthetic opioid and a class A drug. It is that is similar to morphine and heroin but is 100 times stronger than heroin. It is used in healthcare for pain relief as a prescription only medication and is a legally controlled drug. It can be prescribed as a patch, an injection or a lozenge. Tolerance can occur and this means you need a higher and/or more frequent amount of a drug to get the desired effects.
Illicit use of fentanyl is more dangerous than heroin since the risk of overdose is higher. In recent years, fentanyl has been appearing in drugs on the black market mixed in with other drugs such as heroin or cocaine. This mixing occurs because only very small amounts of fentanyl are needed to produce the highs and it is therefore cheaper to manufacture than some other illicit drugs. Fentanyl’s effects on the body and mind are similar to heroin, including euphoria/high, relaxation, drowsiness, confusion, nausea, and at higher doses it can rapidly cause problems breathing and unconsciousness.
Benzodiazepines and Z drugs such as Zopiclone have been widely prescribed over the years to help with sleep and anxiety problems. They may be quite effective in the short term, but regular use can cause tolerance, dependence and addiction. Up to 30% may misuse them purely to get a high though and a UK study showed that 7.7% of people have misused these medications (reference: Kapil, V., Green, J., Lait, C., Wood, D., & Dargan, P. (2014). Misuse of benzodiazepines and Z-drugs in the UK. British Journal of Psychiatry, 205(5), 407-408.) This group of drugs is often misused by opioid users. Benzodiazepines can enhance the intensity and duration of opioid effects, especially when co-injected. Those with a shorter duration of effect such as lorazepam and alprazolam (Xanax) are often misused more than those with a slower onset.
This group of prescription medications acts on the “GABA” system in the brain, hence the name gabapentinoids. GABA is a receptor in the brain and body that when activated, depresses and ‘slows’ the nervous system, with examples such Pregabalin and Gabapentin. They can help with anxiety, pain and epilepsy and are prescribed for these conditions. However, they can be misused since they can sometimes cause some euphoria (for approximately 1-12% of people) and make people feel calmer and more relaxed. Pregabalin and gabapentin may also be misused to enhance the effects of alcohol and drugs including methadone. The number of people misusing them alone seems to be lower but there have been steadily increasing reports of pregabalin and gabapentin misuse in people who misuse other substances. An international review of 59 studies showed gabapentinoid misuse in 1.6% in the general population, and 3–68% of opioid misusers.
(reference: Evoy KE, et al. Misuse and misuse of pregabalin and gabapentin. Drugs 2017;77(4):403–26.) For this reason, pregabalin and gabapentin have been reclassified as Class C controlled drugs in the UK.