Formulary
Codeine phosphate: Indications, Dosing, Side Effects and Interactions
Codeine phosphate clinical drug profile including indications, dosing, side effects, cautions and interactions.
MedNext Academy | 5 min read
Codeine phosphate: Indications, Dosing, Side Effects and Interactions
Codeine phosphate clinical drug profile including indications, dosing, side effects, cautions and interactions.
Indications and dose
**Diarrhoea**
- **Child** (By Mouth): 12-17 years 15-60 mg 3-4 times a day.
- **Adult** (By Mouth): 15-60 mg 3-4 times a day.
**Short-term treatment of acute moderate pain**
- **Child** (By Mouth): 12-17 years 30-60 mg every 6 hours as required for maximum 3 days.
- **Adult** (By Mouth): 30-60 mg every 6 hours as required for maximum 3 days.
**Dry or painful cough**
- **Adult** (By Mouth): 15-30 mg 3-4 times a day, dose to be given using linctus.
**Diarrhoea for codeine phosphate**
- **Child 12-17 years** (By mouth): 15-60 mg 3-4 times a day.
**Short-term treatment of acute moderate pain for codeine phosphate**
- **Child 12-17 years** (By mouth): 30-60 mg every 6 hours as required for maximum 3 days.
Cautions
Adrenocortical insufficiency (reduced dose is recommended); asthma (avoid during an acute attack); central sleep apnoea; convulsive disorders; current or history of mental health disorder; current or history of substance use disorder; debilitated patients (reduced dose is recommended) (in adults); diseases of the biliary tract; elderly (reduced dose is recommended) (in adults); hypotension; hypothyroidism (reduced dose is recommended); impaired respiratory function (avoid in chronic obstructive pulmonary disease); inflammatory bowel disorders; myasthenia gravis; obstructive bowel disorders; prostatic hypertrophy (in adults); shock; urethral stenosis Cautions, further information Dependence and addiction Prolonged use of opioid analgesics may lead to drug dependence and addiction, even at therapeutic doses. There is an increased risk in individuals with current or history of substance use disorder or mental health disorders. See also Important safety information . Central sleep apnoea Opioids cause a dose-dependent increased risk of central sleep apnoea, consider total opioid dose reduction. M Palliative care In the control of pain in terminal illness, the cautions listed should not necessarily be a deterrent to the use of opioid analgesics. M Elderly In adults: Screening Tool of Older Persons' potentially inappropriate Prescriptions (STOPP) criteria to aid medication reviews (see Prescribing in the elderly for information). Potentially inappropriate: if prescribed a strong , oral , or transdermal opioid (i.e. morphine, oxycodone, fentanyl, buprenorphine, diamorphine, methadone, tramadol, pethidine, pentazocine) as first-line therapy for mild pain (WHO analgesic ladder not observed) if used regularly without concomitant laxative (risk of severe constipation) if prescribed a long-acting (modified-release) opioid without a short-acting (immediate-release) opioid for breakthrough pain (risk of persistence of severe pain) Cautions For codeine phosphate Acute abdomen; cardiac arrhythmias; gallstones; not recommended for adolescents aged 12-18 years with breathing problems Cautions, further information Variation in metabolism The capacity to metabolise codeine to morphine can vary considerably between individuals; there is a marked increase in morphine toxicity in patients who are ultra-rapid codeine metabolisers (CYP2D6 ultra-rapid metabolisers) and a reduced therapeutic effect in poor codeine metabolisers.
Contraindications
Acute respiratory depression; comatose patients; head injury (opioid analgesics interfere with pupillary responses vital for neurological assessment); raised intracranial pressure (opioid analgesics interfere with pupillary responses vital for neurological assessment); risk of paralytic ileus Contra-indications For codeine phosphate Acute ulcerative colitis; antibiotic-associated colitis; children under 18 years who undergo the removal of tonsils or adenoids for the treatment of obstructive sleep apnoea; conditions where abdominal distension develops; conditions where inhibition of peristalsis should be avoided; known ultra-rapid codeine metabolisers
Side effects
Common or very common Arrhythmias; confusion; constipation; dizziness; drowsiness; dry mouth; euphoric mood; flushing; hallucination; headache; hyperhidrosis; hypotension (with high doses); miosis; nausea (more common on initiation); palpitations; respiratory depression (with high doses); skin reactions; urinary retention; vertigo; visual impairment; vomiting (more common on initiation); withdrawal syndrome Uncommon Drug dependence; dysphoria; seizure Side-effects, further information Respiratory depression Respiratory depression is a major concern with opioid analgesics and it may be treated by artificial ventilation or be reversed by naloxone. Dependence, addiction, and withdrawal Long term use of opioids in non-malignant pain (longer than 3 months) carries an increased risk of dependence and addiction, even at therapeutic doses. At the end of treatment the dosage should be tapered slowly to reduce the risk of withdrawal effects; tapering from a high dose may take weeks or months. See also Important safety information . Overdose Opioids (narcotic analgesics) cause coma, respiratory depression, and pinpoint pupils. For details on the management of poisoning, see Opioids, under Emergency treatment of poisoning and consider the specific antidote, naloxone hydrochloride. Side-effects For codeine phosphate Frequency not known Abdominal cramps; addiction; appetite decreased; biliary spasm; depression; dyskinesia; dyspnoea; face oedema; fatigue; fever; hyperglycaemia; hypersensitivity; hypothermia; intracranial pressure increased; lymphadenopathy; malaise; mood altered; muscle rigidity (with high doses); nightmare; pancreatitis; restlessness; sexual dysfunction; splenomegaly; ureteral spasm; urinary disorders; vision disorders
Interactions
**Severe interactions:**
- Monoamine oxidase inhibitors: MAOIs taken with pethidine have been associated with severe CNS excitation or depression (including hypertension or hypotension).
**Other interactions (11):**
- Antimuscarinics: codeine phosphate may increase the risk of antimuscarinic side effects such as dry mouth, urine retention and constipation (but this does not generally apply to antimuscarinics...
- Metabolism of codeine is accelerated by rifampicin leading to reduced effect.
- As an opioid analgesic, codeine phosphate may potentiate the effects of tranquillisers such as barbiturates, general anaesthetics, anxiolytics and hypnotics, sedatives and alcohol.
- Possible CNS excitation or depression (hypertension or hypotension) can occur when opioid analgesics are given with antidepressants such as moclobemide (a reversible MAO-A inhibitor).
- The sedative effects of codeine can possibly be increased when given with tricyclic antidepressants, with anxiolytics or hypnotics, or with sedating antihistamines.
- Antipsychotic medicines can enhance hypotensive and sedative effects when opioid analgesics are given with antipsychotics.
Pregnancy
Respiratory depression and withdrawal symptoms can occur in the neonate if opioid analgesics are used during delivery; also gastric stasis and inhalation pneumonia has been reported in the mother if opioid analgesics are used during labour.
Breast feeding
Manufacturer advises avoid (recommendation also supported by MHRA and specialist sources). Present in milk and mothers vary considerably in their capacity to metabolise codeine; risk of opioid toxicity in infant.
Hepatic impairment
Caution in mild to moderate impairment; avoid in severe impairment. M Dose adjustments Reduce dose in mild to moderate impairment. M
Renal impairment
Avoid use or reduce dose; opioid effects increased and prolonged and increased cerebral sensitivity occurs.
Medicinal forms
Solution,Tablet,Solution
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
Inside MedNext for this topic
- 411 MedNext-authored chapters
- 80,000+ MCQ bank
- 15 study modes
- Growing visual cheat sheets
Study modes
- Notes
- MCQ
- Audio
- Video
- Visual
- 3D Anatomy
- Trace
- Flashcards
- Mnemonics
- Image Bank
- Clinical
- Microscopy
- Audio QBank
- Cadaver
- Book Match
Continue reading
Subject HubPharmacology Hub
All pharmacology resources in one place.
Drug SchedulesIndian Drug Schedules
Schedule H, H1, X and G classifications.
FormularyBrowse all drugs
Search 1,850+ drug profiles.
Study Codeine phosphate in the MedNext app
Challenge yourself with targeted pharmacology MCQs on this drug class. Every explanation links back to the chapter that teaches the concept.
Start drug challengeExplore the full formulary

