Codeine phosphate (inj)

Contraindications

• Hypersensitivity to the active ingredient or to any of its excipients
• Breastfeeding
• Hepatic impairment 
• Paediatric patients undergoing a tonsillectomy or adenoidectomy
• CYP2D6 ultra-rapid metabolisers
• Diverticulitis
• Recent bowel surgery
• Acute colitis

Cautions

• Pregnancy
• Moderate to severe renal impairment
• Elderly
• Respiratory depression
• Head injury
• Hypovolaemia
• Repeated administration
• May impair ability to drive or operate machinery

Pregnancy

• Caution;
• There are no adequate data for the use of codeine in pregnant women
• Animal studies are insufficient with respect to effects on pregnancy and embryofetal development. The potential risk for humans is unknown. Codeine should not be used in pregnancy, in particular during the later stages, unless the clinical benefit outweighs the potential risks

Breastfeeding

• Contraindicated
• At normal therapeutic doses codeine and its active metabolite may be present in breast milk at very low doses and is unlikely to adversely affect the breastfed infant. However, if the patient is an ultra-rapid metaboliser of CYP2D6, higher levels of the active metabolite, morphine, may be present in breast milk and on very rare occasions may result in symptoms of opioid toxicity in the infant, which may be fatal
• If symptoms of opioid toxicity develop in either the mother or the infant, then all codeine containing medicines should be stopped and alternative non-opioid analgesics prescribed

Renal impairment

• eGFR ≥50- 89 mL/min/1.73 m²: No dose adjustment recommended
• eGFR <50mL/min/1.73 m²: Caution; dose adjustment recommended

Hepatic Impairment

• Mild to moderate (Child-Pugh Classes A and B): No dose adjustment is recommended
• Limit codeine dose to 1mg per 24 hrs
• Severe (Child-Pugh Class C): Combined codeine-morphine preparations are contraindicated

Elderly

• Caution; no dose adjustment recommended
• Consider initiation at the lower end of the dosing range

Porphyria Information

• Probably not porphyrinogenic (PNP)

Drugs in Sport

• Permitted - no warnings

Central Nervous System Disorders

• Hallucinations
• Altered mood
• Restlessness
• Confusion
• Dependance
• Somnolence
• Headache
• Seizures
• Dysphoria
• Euphoria
• Hyperalgesia
• Dizziness

Cardiovascular Disorders

• Bradycardia
• Palpitations
• Tachycardia
• Flushing
• Orthostatic hypotension
• Oedema

Respiratory Disorders

• Respiratory depression

Gastrointestinal Disorders

• Constipation
• Dry mouth
• Nausea and vomiting
• Abdominal pain
• Anorexia
• Pancreatitis

Hepatobiliary Disorders

• Biliary colic

Genitourinary Disorders

• Sexual dysfunction
• Dysuria
• Ureteral spasm
• Urinary retention

Endocrine and Metabolic Disorders

• Amenorrhoea

Musculoskeletal Disorders

• Muscle rigidity
• Muscle fasciculation

Skin and Subcutaneous Tissue Disorders

• Hyperhidrosis
• Rash
• Urticaria
• Pruritus

Sensory Disorders

• Miosis
• Vertigo

Others

• Hypothermia

• Central nervous system depressants
• Liver enzyme inducers
• Nefopam
• Carbamazepine
• Rifampicin
• Quinidine
• Secobarbital

Codeine is a centrally acting weak analgesic. Codeine exerts its effects though mu opioid receptors. Its analgesic effect is due to its conversion to morphine.