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. Author manuscript; available in PMC: 2013 Jul 2.
Published in final edited form as: Anesthesiology. 2011 Dec;115(6):1363–1381. doi: 10.1097/ALN.0b013e318238bba6

Table 1.

Organ system effects of morphine and its surrogates. The actions summarized in this table are observed for all clinically available opioid agonists

Organ
Systems
Effects Additional information

Central
Nervous
system
↑ Analgesia
↑ Euphoria leading to risk of addiction and abuse
↑Sedation
↓ Rate of respiration
↓ Cough reflex Codeine used for treatment of
pathological cough
↑ Miosis-Constriction of the pupils
↑ Truncal rigidity Most apparent when using fentanyl,
sufentanil, alfentanil
↑ Nausea and vomiting

Peripheral Gastrointestinal system
↑ Constipation
↓ Gastric motility
↓ Digestion in the small intestine
↓ Peristaltic waves in the colon
↑ Constriction of biliary smooth muscle
↑ Esophageal reflux
Other smooth muscle
↑ Depression of renal function
↓ Uterine tone
↑ Urinary retention
Skin
↑ Itching and sweating
↑ Flushing of the face, neck and thorax
Cardiovascular system
↓ Blood pressure and heart rate if cardiovascular
system is stressed
Immune System
↓ Formation of rosettes by human lymphocytes
↓ Cytotoxic activity of natural killer cells
Other
Behavioral restlessness