Co-dydramol (Paracetamol/Dihydrocodeine)
Is It Right for You?
A complete guide to Co-dydramol (Paracetamol/Dihydrocodeine) — what it treats, how it works, dosages, side effects, and when a clinician may prescribe it following an online consultation.
What Is Co-dydramol?
Co-dydramol is a compound analgesic combining two active ingredients in a single tablet: paracetamol (a non-opioid analgesic and antipyretic) and dihydrocodeine tartrate (a semi-synthetic opioid analgesic). It is used for the relief of moderate pain that has not been adequately controlled by non-opioid analgesics alone.
In the UK, co-dydramol is available in four strengths, expressed as the dihydrocodeine/paracetamol content per tablet: 7.46/500 mg (available over the counter as Paramol), 10/500 mg (the standard strength and the formulation supplied when no strength is specified on a prescription), 20/500 mg, and 30/500 mg (both prescription only, for moderate-to-severe pain). The higher strengths provide more pronounced opioid analgesia but also carry greater opioid-related risks.
Co-dydramol is intended for short-term use only. Treatment should be at the lowest effective dose for the shortest possible duration — typically no more than 3 days at the full dose without clinical review — to minimise the risk of opioid dependence, tolerance, and withdrawal, as well as the cumulative risk of paracetamol-related liver injury if the maximum daily dose is inadvertently exceeded from multiple sources.
Co-dydramol at 10/500 mg and above is a prescription-only medication in the UK. A licensed clinician must assess the cause and severity of pain, confirm that simpler analgesics have been tried and have failed, and review contraindications including respiratory disease, head injury, and concurrent CNS depressant use before prescribing.
What Conditions Is Co-dydramol Used For?
Co-dydramol is prescribed for the short-term symptomatic relief of:
Co-dydramol is prescribed for the relief of moderate pain that has not responded adequately to non-opioid analgesics alone (paracetamol, ibuprofen). The opioid component (dihydrocodeine) adds central pain modulation to the peripheral antinociceptive action of paracetamol, providing additional analgesia for musculoskeletal and post-injury pain not fully controlled by simpler agents.
Short-term symptomatic management of acute musculoskeletal pain — including back pain, neck pain, soft-tissue injuries, and joint strains — where simple analgesia has been insufficient. Treatment should be at the lowest effective dose for the shortest possible duration to minimise the risk of dependence and opioid-related adverse effects.
Co-dydramol may be used short term for post-surgical pain, dental pain following extraction or significant dental procedures, and post-traumatic pain where opioid-strength analgesia is clinically appropriate. Use should be time-limited and clinician-supervised.
Migraine attacks unresponsive to first-line treatments (paracetamol, NSAIDs, triptans, or anti-emetics), and severe acute headache where opioid analgesia is clinically appropriate as part of a stepped approach. Routine use of opioids in primary headache disorders is generally discouraged due to the risk of medication-overuse headache and dependence.
Short-term relief of moderate-to-severe menstrual pain (dysmenorrhoea) where NSAIDs are insufficient, contraindicated, or not tolerated. Treatment should be limited to the days of active symptoms within each cycle.
Co-dydramol is intended for short-term use only — typically no more than 3 days at full dose without clinical review. Opioid analgesics carry a significant risk of tolerance, dependence, and addiction, and the paracetamol component imposes a strict 4 g/24-hour ceiling on total daily dose. Co-dydramol is not appropriate for chronic pain management in primary care; persistent pain requires diagnostic review and a structured chronic pain management plan rather than ongoing opioid prescribing.
How Does Co-dydramol Work?
Co-dydramol combines two analgesics with complementary mechanisms that produce additive pain relief through different pathways:
Paracetamol (acetaminophen) — central analgesic and antipyretic: Paracetamol's analgesic and antipyretic effects are believed to result from inhibition of cyclo-oxygenase (COX) enzymes — particularly a central COX variant (sometimes designated COX-3) — leading to reduced prostaglandin synthesis in the central nervous system. Paracetamol may also modulate descending pain pathways via serotonergic and endocannabinoid mechanisms. Unlike NSAIDs, it has minimal peripheral anti-inflammatory activity and does not cause gastric mucosal injury or affect platelet function at therapeutic doses. Paracetamol is metabolised in the liver, primarily via glucuronidation and sulphation; a small fraction is metabolised via cytochrome P450 (CYP2E1) to a reactive intermediate (NAPQI) that is normally detoxified by glutathione — but can accumulate and cause hepatocellular necrosis in overdose.
Dihydrocodeine — opioid analgesic: Dihydrocodeine is a semi-synthetic opioid that acts primarily as an agonist at mu-opioid receptors in the central nervous system, with weaker activity at kappa and delta receptors. Mu-receptor activation in the brain and spinal cord inhibits the transmission of nociceptive (pain) signals and alters the emotional perception of pain. Dihydrocodeine has approximately twice the analgesic potency of codeine and undergoes hepatic metabolism (partly via CYP2D6 to the more active metabolite dihydromorphine), with an oral bioavailability of around 20%. It also produces the typical opioid-class effects including sedation, respiratory depression, constipation, and the potential for tolerance and dependence with prolonged use.
Combined action: The two agents target pain through distinct mechanisms — peripheral and central prostaglandin inhibition (paracetamol) and direct central opioid-receptor activation (dihydrocodeine). The combination provides analgesic efficacy that exceeds either component alone, while allowing each to be used at lower individual doses than would be needed for monotherapy.
Dosages & Administration
The correct dose depends on the type and severity of infection, age, weight, and kidney function. Always follow your clinician's instructions. The table below is for general reference only.
Administration Tips
Take co-dydramol with a full glass of water, with or after food to reduce the risk of nausea.
Take only when needed for pain — do not take regularly 'just in case'. Use the lowest dose that controls your pain, and stop as soon as the pain has resolved.
Allow at least four hours between doses and do not exceed 8 tablets in any 24-hour period. Strict adherence is essential because of the paracetamol content.
Check all other medicines for paracetamol before taking them — paracetamol is in many cold remedies, headache treatments, and combination painkillers. Exceeding 4 g of paracetamol in 24 hours from any combination of sources can cause severe liver damage.
Avoid alcohol while taking co-dydramol. Alcohol significantly increases the risks of both opioid sedation and paracetamol liver injury.
Do not drive or operate machinery until you know how co-dydramol affects you. Driving while impaired by an opioid is illegal in the UK, even with a valid prescription.
Drink plenty of fluid and eat fibre to reduce the risk of opioid-induced constipation. Discuss laxative options with your clinician if constipation becomes troublesome.
Do not stop suddenly after extended use. Your clinician may advise tapering the dose over several days to reduce the risk of withdrawal symptoms.
Side Effects of Co-dydramol
Co-dydramol commonly causes opioid-related side effects (constipation, nausea, drowsiness) which are usually mild and manageable. Serious side effects are uncommon at therapeutic doses but require immediate medical attention when they occur.
- Constipation — very common with opioids; manage proactively with fluid, fibre, and laxatives where needed
- Nausea or vomiting, particularly at initiation
- Drowsiness, sedation, or dizziness
- Dry mouth
- Headache
- Sweating
- Loss of appetite
- Mild euphoria or dysphoria
- Respiratory depression — slowed or shallow breathing, particularly at higher doses, in the elderly, or when combined with alcohol or sedatives; can be fatal in overdose
- Severe allergic reaction (anaphylaxis) — swelling of the face, lips, tongue, or throat; difficulty breathing; widespread rash; requires immediate emergency care
- Hepatotoxicity from paracetamol overdose — even modest excess intake can cause severe, delayed liver injury; symptoms may not appear for 24–72 hours; treatment with N-acetylcysteine is most effective when started early
- Opioid dependence and withdrawal — develops with regular use; withdrawal symptoms include restlessness, sweating, runny nose, watery eyes, yawning, muscle aches, abdominal cramps, and palpitations
- Severe constipation or paralytic ileus — particularly in the elderly or with prolonged use
- Confusion, hallucinations, or seizures — in overdose, in the elderly, or in patients with epilepsy
- Severe hypotension — dizziness on standing, falls, particularly in the elderly
- Adrenal insufficiency — rare; reported with long-term opioid use
The two greatest risks with co-dydramol are accidental paracetamol overdose and opioid-related respiratory depression. Patients must be explicitly counselled that co-dydramol contains paracetamol, and warned not to take any other paracetamol-containing product alongside it. They should also be warned that combining co-dydramol with alcohol, benzodiazepines, or other sedating drugs can cause life-threatening respiratory depression. Both risks are entirely preventable with careful prescribing and patient education.
Drug Interactions
Co-dydramol has several clinically important drug interactions, the most serious of which involve other central nervous system depressants and other paracetamol-containing products. Always disclose all prescription medications, over-the-counter medicines, vitamins, and supplements to your clinician or pharmacist before starting co-dydramol.
Combining co-dydramol with benzodiazepines (such as diazepam, temazepam, lorazepam), Z-drugs (zopiclone, zolpidem), or other sedatives produces additive central nervous system and respiratory depression. This combination significantly increases the risk of profound sedation, respiratory depression, coma, and death. The MHRA strongly advises against co-prescribing unless no alternative exists, and only at the lowest possible doses for the shortest duration.
Alcohol potentiates the central nervous system depressant effects of dihydrocodeine, increasing sedation, respiratory depression, and the risk of accidents. Alcohol also increases the risk of paracetamol-induced liver damage, particularly in chronic heavy drinkers. Alcohol should be avoided during co-dydramol treatment.
Concurrent use of other opioid analgesics (codeine, tramadol, morphine, oxycodone) produces additive opioid effects, including respiratory depression, sedation, and increased risk of overdose. Co-dydramol must not be combined with other opioid-containing products without explicit clinical advice.
Co-dydramol contains 500 mg of paracetamol per tablet. Combining with any other paracetamol-containing product (Lemsip, Calpol, co-codamol, many cold and flu remedies) risks exceeding the 4 g/24-hour maximum and causing severe, potentially fatal liver damage. Patients must read all medicine labels carefully.
Concurrent use with MAOIs (phenelzine, tranylcypromine, moclobemide) or within 14 days of stopping them can cause severe and unpredictable reactions including hypertension, hyperpyrexia, and CNS excitation or depression. Co-dydramol should not be used in patients receiving or recently treated with MAOIs.
Dihydrocodeine slows gastric emptying and can delay or reduce the absorption of orally administered medication, including some antibiotics and antiepileptics. It can also enhance the anticholinergic side effects of tricyclic antidepressants, antihistamines, and antimuscarinic drugs, increasing the risk of constipation, urinary retention, and confusion.
Important Warnings
Co-dydramol contains paracetamol. Exceeding the maximum daily dose (4 g of paracetamol per 24 hours from all sources) can cause severe, delayed, and potentially fatal liver damage. Overdose may not produce immediate symptoms, but liver injury becomes apparent 24–72 hours later. Anyone who has taken too much should seek immediate medical attention even if they feel well.
Dihydrocodeine is an opioid analgesic and can cause physical and psychological dependence with regular use beyond a few days. Tolerance and dependence can develop even at therapeutic doses. Treatment should be at the lowest effective dose for the shortest possible time (typically no more than 3 days at full dose without clinical review). Abrupt cessation after extended use can precipitate withdrawal symptoms.
The most serious risk of opioid analgesics is respiratory depression — slowed or shallow breathing that can be fatal in overdose. This risk is greatest in the elderly, debilitated patients, those with chronic obstructive pulmonary disease (COPD), asthma, or sleep apnoea, and when combined with other CNS depressants such as alcohol or benzodiazepines.
Co-dydramol can cause drowsiness, dizziness, and impaired alertness, particularly at initiation. You must not drive, operate machinery, or perform tasks requiring full alertness until you know how the medication affects you. Driving while impaired by an opioid is a criminal offence in the UK, even with a valid prescription.
Co-dydramol is contraindicated in patients with respiratory depression, acute or severe bronchial asthma, paralytic ileus, or known hypersensitivity to paracetamol or dihydrocodeine. It is also contraindicated in patients with raised intracranial pressure or head injury, where opioid-induced respiratory depression and effects on pupil size can interfere with neurological assessment.
Opioids cross the placenta and can cause neonatal respiratory depression and withdrawal symptoms if used at delivery or chronically in late pregnancy. They also pass into breast milk and can cause infant sedation and breathing problems. Co-dydramol is generally avoided in pregnancy and breastfeeding; if essential, the lowest effective dose for the shortest time should be used, and infants monitored carefully.
Speak to a Clinician About Treatment
Getting advice no longer means sitting in a waiting room. Through The GP Service, you can consult with a licensed clinician in minutes — from home, on your lunch break, or wherever works for you. If treatment is clinically appropriate, your clinician can issue a prescription during the consultation. A consultation does not guarantee a prescription.
The treatment you need, when you need it.
Co-dydramol FAQs
Co-dydramol is a combination painkiller containing two active ingredients: paracetamol and dihydrocodeine (a weak opioid). It is used for moderate pain that has not responded adequately to paracetamol or ibuprofen alone. It is available in four strengths: 7.46/500 mg, 10/500 mg, 20/500 mg, and 30/500 mg — the first number is the dihydrocodeine dose, the second is paracetamol.
The standard adult dose is one or two tablets every four to six hours as needed, with a maximum of eight tablets in any 24-hour period. The maximum total paracetamol intake from all sources must not exceed 4 g in 24 hours. Co-dydramol is intended for short-term use — typically no more than 3 days at the full dose without clinical review.
No — never combine co-dydramol with other paracetamol-containing products (such as Lemsip, Calpol, co-codamol, or many cold and flu remedies), as this risks exceeding the 4 g/24-hour maximum paracetamol limit and causing severe, potentially fatal liver damage. Always check the active ingredients of any medicine you take alongside co-dydramol.
You should not drink alcohol while taking co-dydramol. Alcohol increases the sedative and respiratory depressant effects of the dihydrocodeine, raising the risk of accidents and dangerous over-sedation. It also significantly increases the risk of paracetamol-induced liver damage.
Co-dydramol can cause drowsiness, dizziness, and impaired alertness. You must not drive, operate machinery, or carry out tasks requiring full attention until you know how the medication affects you. Driving while impaired by an opioid is a criminal offence in the UK, even with a valid prescription.
Yes — dihydrocodeine is an opioid and can cause both physical and psychological dependence, particularly with use beyond a few days at full dose. Tolerance, where you need more of the drug for the same effect, can also develop. This is why co-dydramol should be used at the lowest effective dose for the shortest possible time, and why you should not stop suddenly after extended use — your clinician will help you taper safely.
The most common side effects are constipation, nausea, dizziness, and drowsiness. Constipation in particular is very common with opioids — drink plenty of fluid, eat fibre, and discuss laxative options with your clinician if needed. Less commonly, co-dydramol can cause vomiting, dry mouth, headache, or skin rash. Serious side effects (respiratory depression, severe allergic reaction) require immediate medical attention.
If you forget a dose, take it as soon as you remember unless it is nearly time for the next dose — in which case skip the missed dose and continue with your normal schedule. Do not take a double dose to make up for the missed one. Because co-dydramol is taken as needed for pain, an occasional missed dose is not a problem.