
Originally Posted by
madmuscler
Copy and pasted Opiates can cause peripheral edema and the effect is dose-related. The exact mechanism of opiate-induced edema is unclear but the following plausible mechanisms may be involved: a) by causing histamine release, morphine results in venodilation and this effect is dose-related (Grossman, 1996, Gardener-Nix 2002); b) opioids cause vasopressin release from posterior pituitary and this results in antidiuresis and retention of fluids leading to edema; and c) it's been shown in animals that by activating central opioid receptors, opioids enhance renal tubular sodium reabsorption -- this can cause edema and may block the aquaporins leading to retention of water (Huidoboro, 1981).