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Weak opioid analgesic

Dihydrocodeine

Brand names: DHC Continus (MR), DF118 Forte

Dihydrocodeine is a moderate opioid for moderate-to-severe pain; it is a controlled drug.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 120 mg every 12 hours (one 120 mg prolonged-release tablet 12-hourly)
Route: Oral — prolonged-release tablets. SPC §4.2: 'Method of administration Oral.'
Frequency: Every 12 hours
SCOPE: this draft covers ONLY the oral PROLONGED-RELEASE tablet for pain. The fetched SPC is for the 120 mg prolonged-release presentation; it carries no immediate-release regimen and no subcutaneous or intramuscular regimen, so the page's IR (30 mg 4-6 hourly) and SC/IM routes are NOT sourced here and are not asserted. Verbatim SPC §4.2: 'Adults and children over 12 years: The usual dose is one tablet 12-hourly. Elderly: Dosage should be reduced. Prior to starting treatment with opioids, a discussion should be held with patients to put in place a strategy for ending treatment with dihydrocodeine in order to minimise the risk of addiction and drug withdrawal syndrome (see section 4.4).' No maximum daily dose is stated anywhere in the fetched SPC, so maxDose is left empty rather than inferred. §4.4 warning that bears on dosing: 'Do not use for acute post-operative pain owing to the increased risk of persistent post-operative opioid use (PPOU) and opioid-induced ventilatory impairment (OIVI).' Also §4.4: 'Concomitant use of dihydrocodeine and sedative medicines such as benzodiazepines or related drugs may result in sedation, respiratory depression, coma and death... the lowest effective dose should be used, and the duration of treatment should be as short as possible.' The US TREZIX label in this bundle ('The usual adult dosage is two (2) TREZIX capsules orally every four (4) hours... No more than five (5) doses, or ten (10) capsules should be taken in a 24-hour period') is a paracetamol/caffeine/dihydrocodeine combination with unquantified components in the fetched text and is deliberately not carried across.

Paediatric dose

Route: Oral
Frequency: Every 12 hours (over 12 years only)
The fetched SPC gives NO mg/kg dosing, so no weight-based calculation is possible and dosePerKg is null. Verbatim §4.2: 'Adults and children over 12 years: The usual dose is one tablet 12-hourly' (i.e. 120 mg 12-hourly with this prolonged-release presentation) and 'Paediatric population Children 12 years or under: Not recommended.' §4.8 adds: 'Neonatal respiratory depression and withdrawal symptoms may occur in the newborn of mothers undergoing treatment with dihydrocodeine.' Verify any paediatric opioid dose against a children's formulary before prescribing.

Dose adjustments

Renal

No numeric renal adjustment is given in the fetched SPC. §4.4 lists 'severe renal dysfunction' among the conditions in which 'Dihydrocodeine should be administered with caution'. §4.2 states only 'Elderly: Dosage should be reduced'.

Hepatic

No numeric hepatic adjustment is given in the fetched SPC. §4.4 lists 'impairment of hepatic function' among the conditions in which 'Dihydrocodeine should be administered with caution'.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

  • Hypersensitivity to the active substance or to any of the excipients (§4.3)
  • Severe respiratory depression with hypoxia (§4.3)
  • Severe chronic obstructive lung disease (§4.3)
  • Severe cor pulmonale (§4.3)
  • Severe bronchial asthma; and, because dihydrocodeine may cause the release of histamine, it should not be given during an asthma attack (§4.3)
  • Paralytic ileus (§4.3)
  • Acute alcoholism (§4.3)
  • Rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption (excipient-related, §4.3)

Side effects

  • Common (>=1%) per §4.8: somnolence, dizziness, headache, constipation, dry mouth, nausea, vomiting, abdominal pain
  • Uncommon (<1%) per §4.8: confusional state, hallucination, mood altered, dysphoria, convulsions, paraesthesia, sedation, blurred vision, vertigo, hypotension, flushing, dyspnoea, diarrhoea, biliary colic, hepatic enzymes increased, hyperhidrosis, pruritus, rash, urticaria, urinary retention, uretic spasm, decreased libido, asthenia, fatigue, malaise
  • Respiratory depression — §4.4: 'The primary risk of opioid excess is respiratory depression'
  • Sleep apnoea syndrome, including central sleep apnoea and sleep-related hypoxaemia; opioids may worsen pre-existing sleep apnoea (§4.4, §4.8)
  • Drug dependence (addiction), drug tolerance and drug withdrawal syndrome, including neonatal drug withdrawal syndrome (§4.8)
  • Paralytic ileus (§4.8)
  • Angioedema (§4.8)
  • Medication-overuse headache — §4.8: 'Prolonged use of a painkiller for headaches can make them worse'

Monitoring

  • Signs and symptoms of respiratory depression and sedation — §4.4: 'The patients should be followed closely for signs and symptoms of respiratory depression and sedation', and patients/carers should be informed of these symptoms
  • Central sleep apnoea — §4.4: 'In patients who present with CSA, consider decreasing the total opioid dosage'
  • Dependence, tolerance and misuse risk — §4.4 advises a comprehensive medication and psychiatric history before starting, with 'additional support and monitoring... when prescribing for patients at risk of opioid misuse'
  • Agree an exit strategy before starting — §4.2: a discussion 'to put in place a strategy for ending treatment with dihydrocodeine'
  • Neonates of mothers treated during pregnancy should be monitored for respiratory depression (§4.6)

Clinical monograph

How it works

It is an opioid agonist (mainly at mu receptors); unlike codeine, its analgesia depends less on CYP2D6 conversion.

Prescribing in practice

  • Constipation, nausea and drowsiness are common; co-prescribe a laxative.
  • Reduce the dose in renal or hepatic impairment and in older or frail patients.
  • There is additive sedation and respiratory depression with other CNS depressants; counsel on dependence.

Monitoring

Review pain relief, bowel habit and signs of dependence.

Counselling the patient

  • It commonly causes constipation — take the laxative provided.
  • Do not combine it with alcohol or other sedatives.
  • Take it only as prescribed; it can be habit-forming.

Evidence & guidelines

A moderate-opioid option on the analgesic ladder for moderate-to-severe pain.

Reference: SmPC DHC Continus; NICE NG193 (chronic primary pain 2021); WHO Analgesic Ladder; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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