dihydrocodeine tartrate + paracetamol: clinical use

Prescribing considerations

• Confirm the exact preparation because strengths, legal status and product-specific licensing differ.
• Account for paracetamol from every source and assess hepatic, renal and alcohol-related risk.
• Assess respiratory reserve, gastrointestinal obstruction, falls risk, cognitive impairment and concurrent sedatives.
• Review benefit, sedation, constipation, tolerance, hyperalgesia, dependence and signs of non-medical use.
• Explain impairment and drug-driving considerations.

Contraindications and cautions

• For selected Paramol: hypersensitivity to an ingredient, respiratory depression or obstructive airways disease.
• Delayed gastric emptying, paralytic ileus and specified severe diarrhoeal conditions.
• Acute alcoholism, convulsive disorders, head injury or raised intracranial pressure.
• Known CYP2D6 ultra-rapid metabolism.
• Use following tonsillectomy or adenoidectomy for obstructive sleep apnoea in patients under 18.
• Pregnancy and breastfeeding are product-specific contraindications for selected Paramol.

Monitoring

• Analgesic benefit and continuing clinical need.
• Sedation, respiratory rate and mental state, especially with other central nervous system depressants.
• Constipation, urinary retention and features of ileus.
• Total paracetamol exposure and signs of hepatic injury in at-risk patients.
• Dependence, withdrawal, tolerance or opioid-induced hyperalgesia.
• Anticoagulation response when relevant regular use occurs with warfarin.

Clinical pharmacology

Paracetamol is absorbed from the gastrointestinal tract, predominantly conjugated in the liver and excreted in urine. Dihydrocodeine is absorbed orally and metabolised in the liver through several pathways, including partial CYP2D6 conversion to active dihydromorphine; metabolic variation can alter efficacy and toxicity.

Formulation and product differences

• Selected Paramol is an immediate-release oral tablet containing both active ingredients.
• Other UK co-dydramol tablets contain different amounts of dihydrocodeine while retaining paracetamol, so products should not be assumed interchangeable.
• The selected product should preferably be taken during or after meals.