codeine/acetaminophen

Action and Spectrum

Actions and Spectrum 

codeine acts by attaching to opioid receptors in the spinal cord, brain and other areas of the body. acetaminophen, referred to as paracetamol, is an antipyretic and non-opioid analgesic.

It functions by preventing the synthesis of specific molecules known as prostaglandins, which are essential for the transmission of pain signals and the control of body temperature.

Drug Interaction

Adverse Reaction

Frequency not defined  

For acetaminophen 

Laryngeal edema  

Anaphylactoid reaction 

Leukopenia  

Pancytopenia 

Thrombocytopenic purpura 

Angioedema  

Agranulocytosis 

Hepatotoxicity 

Neutropenia 

Thrombocytopenia 

Pruritic maculopapular rash 

Urticaria 

For (codeine) 

Constipation 

Malaise  

Dyspnea 

Weakness 

Restlessness 

Tachycardia or bradycardia   

Burning at injection site 

Headache 

Xerostomia 

Ureteral spasm  

Blurred vision 

Histamine release 

Confusion  

Rash 

Nausea  

Vomiting 

Decreased urination 

Paradoxical CNS stimulation 

Dizziness 

Urticaria 

Anorexia 

False feeling of well being 

Lightheadedness 

Drowsiness 

Hypotension 

Black Box Warning

Black Box Warning 

acetaminophen/codeine users, including patients, are put at risk for opioid addiction, abuse, and misuse, all of which can result in overdose and death. With usage of acetaminophen/codeine, significant, life-threatening, or fatal respiratory depression may ensue.  

Long-term acetaminophen/codeine use during pregnancy can cause newborn opioid withdrawal syndrome, which might be fatal if undiagnosed and untreated.  

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

• The combination medication should not be used in individuals who have a known hypersensitivity or allergy to codeine/acetaminophen.  
• codeine is a respiratory depressant, and the combination medication should be avoided or used with extreme caution in individuals with severe respiratory insufficiency.  

Caution: 

• codeine can suppress respiration, so caution should be exercised when using codeine/ acetaminophen in individuals with pre-existing respiratory conditions.  
• acetaminophen is metabolized in the liver, and individuals with liver impairment or liver disease should use codeine/acetaminophen with caution.  
• codeine/acetaminophen should be used with caution in elderly individuals, as they may be more susceptible to adverse effects. 

Pregnancy / Lactation

Pregnancy warnings:     

Pregnancy category: N/A 

Lactation: Excretion into human milk is known in low amounts   

Pregnancy Categories:         

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women.  

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women. 

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits. 

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women. 

Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology  

The opioid analgesic codeine works by binding to opioid receptors in the central nervous system. In order to have analgesic effects, it predominantly binds to mu-opioid receptors, which are involved in modulating pain.  

acetaminophen prevents the production of prostaglandins, which are involved in the signaling of pain and fever. acetaminophen primarily affects the central nervous system (CNS) to lessen pain and temperature perception. 

Pharmacodynamics 

codeine reduces pain perception by controlling the release of substance P and other neurotransmitters involved in pain signaling. Through this modulation, pain is reduced as a result of a reduction in the amount of pain signals that are sent from peripheral nerves to the brain.   

acetaminophen primarily affects the central nervous system, in particular the hypothalamus, which oversees controlling body temperature. This suppresses the creation of prostaglandins. 

Pharmacokinetics 

Absorption   

codeine is well-absorbed from the gastrointestinal tract after oral administration.  

acetaminophen is rapidly and completely absorbed from the gastrointestinal tract.  

Distribution 

codeine/acetaminophen both extensively distributed throughout the body.  

Metabolism 

codeine is metabolized primarily by the enzyme CYP2D6 in the liver.  

acetaminophen is primarily metabolized in the liver through conjugation with sulfate.  

Elimination and excretion 

Both codeine/acetaminophen and their metabolites are excreted primarily in the urine. 

Adminstartion

Administration 

codeine/acetaminophen is available in tablet or capsule form and is administered orally.  

Patient Information Leaflet

Patient information leaflet 

Generic Name: codeine/acetaminophen 

Why do we use codeine/acetaminophen? 

codeine/acetaminophen is a combination medication used for the treatment of mild to moderate pain. It is commonly indicated for various types of pain, including dental pain, postoperative pain, musculoskeletal pain, and pain associated with injury or medical conditions.