Codeine, Tramadol and Other Opioid Painkillers: Benefits, Side Effects and Dependence Risks

Opioid painkillers can be very effective for short-term severe pain, such as after surgery or an injury. But they are much less useful for long-term pain, and the risks of dependence and harm rise the longer you take them.

Imagine being given codeine for a back injury. It helps at first, so you keep taking it. Months later, the pain is no better, you feel constipated and foggy, and when you miss a dose you feel shaky and anxious. You realise you might need help to stop.

What opioids are

Opioids are a group of painkillers that act on opioid receptors in the brain, spinal cord and gut. Weaker opioids include codeine and dihydrocodeine. Tramadol is a moderate-strength opioid that also affects serotonin and noradrenaline. Stronger opioids include morphine, oxycodone and fentanyl.,Codeine is often combined with paracetamol in one tablet. In some countries, low-dose codeine combinations are available from pharmacies, while in others they need a prescription.

When opioids help

• Severe short-term pain after surgery or injury
• Severe pain in some acute conditions, such as kidney stones
• Pain at the end of life and in cancer, where stronger opioids are often essential
• They are usually not recommended as a long-term treatment for most chronic pain, such as back pain, fibromyalgia or headaches

Common side effects

• Constipation, which is very common; a laxative is often needed
• Nausea and vomiting
• Drowsiness and dizziness
• Confusion, especially in older adults
• Itching
• Dry mouth
• Low mood and reduced sex drive with long-term use

Codeine: why it works differently for different people

Codeine works by being converted into morphine by the liver. Genetic differences mean some people convert very little, getting almost no pain relief, while others convert it very quickly, which can lead to dangerous morphine levels.,Because of this, codeine is not recommended for children under 12, for many teenagers after tonsil surgery, or for breastfeeding mothers in several countries, as babies have been harmed by morphine passed in breast milk.

Tramadol: specific risks

Tramadol can cause seizures, particularly at high doses or in people with epilepsy. It can also interact with antidepressants and other medicines that affect serotonin, causing serotonin syndrome. It is a controlled drug in many countries because of misuse and dependence.

Tolerance, dependence and addiction

With regular use, the body gets used to opioids. This is called tolerance, and it means the same dose gives less pain relief. Dependence means stopping suddenly causes withdrawal symptoms, such as anxiety, sweating, aches, diarrhoea and difficulty sleeping. Dependence can happen even when opioids are taken exactly as prescribed.,Addiction is different: it involves craving the medicine and continuing to take it despite harm. Anyone can develop problems, and needing help is nothing to be ashamed of.

Overdose risk

Opioids can slow or stop breathing, especially at high doses, in older adults, in people with lung or kidney problems, and when combined with alcohol, benzodiazepines, gabapentinoids or sleeping tablets. Signs of overdose include extreme drowsiness, pinpoint pupils, slow or shallow breathing, blue lips and being unresponsive.,If you suspect an overdose, call emergency services immediately. In many countries, naloxone, a medicine that can reverse opioid overdose, is available to families and friends of people at risk.

Using opioids safely

• Use the lowest dose for the shortest time
• Do not drive if you feel drowsy
• Avoid alcohol
• Do not share your medicines
• Store them securely, away from children and teenagers
• Return unused medicines to a pharmacy
• Have a plan with your healthcare provider for when and how to stop

Stopping opioids

If you have taken opioids regularly for more than a couple of weeks, reduce them gradually with support from your healthcare provider, rather than stopping suddenly. Many people find their pain is no worse, and sometimes better, after reducing opioids. Support services are available if you are finding it hard to cut down.

Frequently asked questions

Is codeine safe in pregnancy?

Use only if advised by a healthcare provider. Regular use late in pregnancy can cause withdrawal in the newborn.

Can I buy codeine over the counter?

It depends on your country. Over-the-counter codeine is usually limited to short-term use, often three days.

What should I take for constipation?

A stimulant laxative or softener is often recommended. Ask your pharmacist.

But what else can I take for long-term pain?

Options include physical therapies, exercise, pain management programmes, psychological approaches and, for some conditions, non-opioid medicines. A pain specialist can help.

Related: Ibuprofen vs paracetamol · Gabapentin and pregabalin

Sources: World Health Organization, National Institute for Health and Care Excellence, UK Medicines and Healthcare products Regulatory Agency, US Centers for Disease Control and Prevention opioid prescribing guideline (2022).