Geriatric patients should be supervised while on this medication, and consideration of reduced dosage should be based on response. Codeine should only be used with caution in patients with kidney or liver impairment. Care should be taken in patients with asthma, hypothyroidism, and in patients with a history of drug abuse. Tolerance and dependency may occur with prolonged use.
CYP2D6 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 therapeutic 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% |
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
Sunset Yellow may cause allergic reactions.
This product contains sorbitol (E420). Patients with rare hereditary problems of fructose intolerance should not take this medicine.