Paediatric population
Not recommended for children under 12 years of age.
CY2D6 metabolism
Codeine is metabolised by the liver enzyme CYP2D6 into morphine, its active metabolite. If a patient has a deficiency or is completely lacking this enzyme an adequate analgesic effect will not be obtained. Estimates indicate that up to 7% of the Caucasian population may have this deficiency. However, if the patient is an extensive or ultra-rapid metaboliser there is an increased risk of developing side effects of opioid toxicity even at commonly prescribed doses. These patients convert codeine into morphine rapidly resulting in higher than expected serum morphine levels.
General symptoms of opioid toxicity include confusion, somnolence, shallow breathing, small pupils, nausea, vomiting, constipation and lack of appetite. In severe cases this may include symptoms of circulatory and respiratory depression, which may be life-threatening and very rarely fatal. Estimates of prevalence of ultra-rapid metabolisers in different populations are summarized below:
| Population | Prevalence % |
| African/Ethiopian | 29% |
| African American | 3.4% to 6.5% |
| Asian | 1.2% to 2% |
| Caucasian | 3.6% to 6.5% |
| Greek | 6.0% |
| Hungarian | 1.9% |
| Northern European | 1%-2% |
Post-operative use in children
There have been reports in the published literature that codeine given post-operatively in children after tonsillectomy and/or adenoidectomy for obstructive sleep apnoea, led to rare, but life-threatening adverse events including death (see also section 4.3). All children received doses of codeine that were within the appropriate dose range; however there was evidence that these children were either ultra-rapid or extensive metabolisers in their ability to metabolise codeine to morphine.
Children with compromised respiratory function
Codeine is not recommended for use in children in whom respiratory function might be compromised including neuromuscular disorders, severe cardiac or respiratory conditions, upper respiratory or lung infections, multiple trauma or extensive surgical procedures. These factors may worsen symptoms of morphine toxicity.
Do not exceed the stated dose.
Do not take concurrently with any other paracetamol or codeine containing compounds.
This product may cause drowsiness.
Keep out of the reach and sight of children.
Care is advised in the administration of this preparation to patients with impaired kidney or liver function and in those with hypertension, hypothyroidism, adrenocortical insufficiency, prostatic hypertrophy, urinary retention, susceptibility to angle-closure glaucoma, shock, obstructive bowel disorders, acute abdominal conditions (e.g. peptic ulcer), recent gastrointestinal surgery, gallstones, myasthenia gravis, a history of cardiac arrhythmias or convulsions, and in patients with a history of drug abuse or emotional instability.
Codeine may induce faecal impaction, producing incontinence, spurious diarrhoea, abdominal pain and rarely colonic obstruction. Elderly patients may metabolise or eliminate opioid analgesics more slowly than younger adults.
Administration of pethidine and possibly other opioid analgesics to patients taking a monoamine oxidase inhibitor (MAOI) has been associated with very severe and sometimes fatal reactions. See also Section 4.3 regarding contraindication of taking Syndol with MAOIs because of the doxylamine component.
Risks from concomitant use of opioids and benzodiazepines
Concomitant use of opioids, including codeine, and sedative medicines such as benzodiazepines or related drugs may result in sedation, respiratory depression, coma, and death. Because of these risks, concomitant prescribing of sedative medicines, such as benzodiazepines or related drugs, with opioids should be reserved for patients for whom alternative treatment options are not possible.
If a decision is made to prescribe codeine concomitantly with sedative medicines such as benzodiazepines, the lowest effective dose should be used, and the duration of treatment should be as short as possible (see also general dose recommendation in section 4.2). The patients should be followed closely for signs and symptoms of respiratory depression and sedation . In this respect, it is strongly recommended to inform patients and their environment to be aware of these symptoms (see section 4.5).
Risks from concomitant use of opioids and alcohol
Concomitant use of opioids, including codeine, with alcohol may result in sedation, respiratory depression, coma and death. Concomitant use with alcohol is not recommended (see section 4.5).
The hazards of overdose are greater in those with non-cirrhotic alcoholic liver diseases.
Co-administration of enzyme-inducing antiepileptic medications may increase toxicity; doses should be reduced.
E110 (sunset yellow) and E104 (quinoline yellow) may cause allergic reactions.
Patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take this medicine.
This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially 'sodium-free'.
The label will state:
Front of Pack:
• Can cause addiction
• For three days use only
Back of Pack:
• For the short term treatment of acute moderate pain where other painkillers have not worked. Do not take less than four hours after taking other pain killers. This medicine is used for tension headaches, migraines, muscular pains and tension.
• Do not take more medicine than the label tells you to. If you do not get better, talk to your doctor.
• Do not take anything else containing paracetamol whilst taking this medicine.
• Talk to your doctor at once if you take too much of this medicine, even if you feel well.
• If you need to take this medicine continuously for more than three days you should see your doctor or pharmacist.
• This medicine contains codeine which can cause addiction if you take it continuously for more than three days. If you take this medicine for headaches for more than three days it can make them worse.
The leaflet will state:
Important things you should know about Syndol
• This medicine can only be used for the short term treatment of acute moderate pain where other painkillers have not worked.
• You should only take this product for a maximum of three days at a time. If you need to take it for longer than three days you should see your doctor or pharmacist for advice.
• This medicine contains codeine which can cause addiction if you take it continuously for more than three days. This can give you withdrawal symptoms from the medicine when you stop taking it.
• If you take this medicine for headaches for more than three days it can make them worse.
Section 1: What Syndol is and what it is used for
• Syndol is used for the short term treatment of acute moderate pain which is not relieved by paracetamol, ibuprofen and aspirin alone such as headache, including muscle contraction or tension headache, migraine, neuralgia, period pain, toothache and other dental pain, muscular and rheumatic aches and pains and for pain relief following surgery or dental procedures.
Section 2: What you need to know before you take Syndol
• This medicine contains codeine which can cause addiction if you take it continuously for more than three days. This can give you withdrawal symptoms from the medicine when you stop taking it.
• If you take this medicine for headaches for more than three days it can make them worse.
• Do not take Syndol if you know that you metabolise very rapidly codeine into morphine.
(In the “Pregnancy and breast-feeding” subsection)
If you are pregnant or breast feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.
Do not take Syndol whilst breastfeeding. Codeine and morphine passes into the breast milk.
Section 3: How to take Syndol
• Do not take for more than 3 days. If you need to use this medicine for more than three days you must speak to your doctor or pharmacist.
• This medicine contains codeine and can cause addiction if you take it continuously for more than three days. When you stop taking it you may get withdrawal symptoms. You should talk to your doctor or pharmacist if you think you are suffering from withdrawal symptoms.
Section 4: Possible Side effects
• Reporting of side effects
If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.
By reporting side effects you can help provide more information on the safety of this medicine.
• How do I know if I am addicted?
If you take the medicine according to the instructions on the pack it is unlikely that you will become addicted to the medicine. However, if the following apply to you it is important that you talk to your doctor:
• You need to take the medicine for longer periods of time.
• You need to take more than the recommended dose.
When you stop taking the medicine you feel very unwell but you feel better if you start taking the medicine again.