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Weak opioid analgesic Pregnancy: Avoid 3rd trimester — neonatal opioid withdrawal syndrome. Earlier pregnancy: paracetamol alone preferred.

Dihydrocodeine

Brand names: DHC Continus (MR), DF118 Forte

Adult dose

Dose: Immediate-release: 30 mg every 4–6 hours; max 240 mg/day. Modified-release (DHC Continus): 60–120 mg BD. SC/IM (DF118 Forte): 50 mg every 4–6 hours.
Route: Oral / SC / IM
Frequency: Every 4–6 hours (IR) or BD (MR)
Max: 240 mg/day (oral)
Roughly twice as potent as codeine — but co-prescribe paracetamol for additive analgesia. NOT a CYP2D6 prodrug (unlike codeine) — less inter-individual variability.

Paediatric dose

Route: Oral
Frequency: Every 6 hours
≥4 yrs: 0.5–1 mg/kg every 4–6 hours (max 30 mg/dose). 12–18 yrs: adult dose. Avoid post-tonsillectomy/adenoidectomy (MHRA warning extends class concerns).

Dose adjustments

Renal

eGFR 10–50: 75% of dose. eGFR <10: 50% of dose; lengthen interval to every 6–8 hours; metabolites accumulate.

Hepatic

Reduce dose; avoid in severe impairment.

Clinical pearls

  • Roughly twice as potent as codeine, half as potent as morphine — useful step between codeine/paracetamol and oral morphine in WHO analgesic ladder (though 'weak opioid' tier has been deprioritised in recent guidance).
  • Unlike codeine, dihydrocodeine is NOT a CYP2D6 prodrug — analgesic effect is more predictable across individuals; useful when codeine ineffective due to poor metabolism.
  • MR formulation (DHC Continus) provides 12-hour cover — useful for chronic pain where opioid is essential. Avoid in opioid-naïve elderly (start with IR).
  • All oral compound paracetamol+dihydrocodeine products (co-dydramol 10/500, 20/500, 30/500) carry max paracetamol 4 g/day — counsel as for co-codamol.
  • Used as alternative to methadone/buprenorphine for opioid maintenance in some EU systems — not licensed for OUD in UK.
  • Constipation rate similar to morphine — co-prescribe regular macrogol or senna from day 1.

Contraindications

  • Severe respiratory depression
  • Acute severe asthma
  • Paralytic ileus
  • Raised intracranial pressure or head injury
  • MAOI within 14 days
  • Acute alcohol intoxication

Side effects

  • Constipation (very common — co-prescribe laxative for regular use)
  • Nausea, vomiting (often tolerance develops 5–7 days)
  • Drowsiness, dizziness
  • Respiratory depression (risk with alcohol/benzodiazepines)
  • Dependence and tolerance
  • Pruritus, miosis
  • Urinary retention
  • Hypotension

Interactions

  • CNS depressants (alcohol, benzodiazepines, gabapentinoids): additive sedation, fatal respiratory depression
  • MAOIs: serotonin syndrome — avoid 14 days
  • Tramadol, other opioids: additive
  • Naloxone: reversal agent

Monitoring

  • Pain score, function
  • Bowel function
  • Sedation in elderly
  • Review for ongoing need at 4 weeks (acute) or 3-monthly (chronic)

Reference: BNFc; BNF 90; BNF for Children 2024; SmPC DHC Continus; NICE NG193 (chronic primary pain 2021); WHO Analgesic Ladder. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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