Hypotension opioid-induced

Morphine produces venous and arteriolar dilation, which may result in orthostatic hypotension. Hypovolemic patients are more susceptible to morphine-induced hypotension. Morphine is often considered the opioid of choice to treat pain associated with myocardial infarction, as it decreases myocardial oxygen demand. 

PROCARBAZINE ANALGESICS-OPIOIDS Unpredictable reactions may occur associated with hypotension and respiratory depression when procarbazine is co-administered with alfentanil, fentanyl, sufentanil or morphine Opioids cause hypotension due to arterial and venous vasodilatation, negative inotropic effects and a vagally induced bradycardia. Procarbazine can cause postural hypotension. Also attributed to an accumulation of serotonin due to inhibition of MAO Recommended that a small test dose (one-quarter of the usual dose) be administered in initially to assess the response... 

Opioids cause hypotension due to arterial and venous vasodilatation, negative inotropic effects and a vagally induced bradycardia. Procarbazine can cause postural hypotension. Also attributed to accumulation of serotonin due to inhibition of MAO... 

Therapeutic doses of morphine have minimal effects on blood pressure, cardiac rate, or cardiac rhythm when patients are supine however, morphine does produce venous and arteriolar vessel dilatation, and orthostatic hypotension may result. Hypovolemic patients are more susceptible to morphine-induced cardiovascular changes (e.g., decreases in blood pressure). Because morphine prompts a decrease in myocardial oxygen demand in ischemic cardiac patients, it is often considered the drug of choice when using opioids to treat pain associated with myocardial infarction. 

Morphine-like opioids should be used with caution in patients who have a decreased blood volume because these agents can aggravate hypovolemic shock. Morphine should be used with great care in patients with cor pulmonale because deaths after ordinary therapeutic doses have been reported. The concurrent use of certain phenothiazines may increase the risk of morphine-induced hypotension. 

There is evidence that chlorpromazine can increase the activity of the liver microsomal enzymes so that the metabolism of pethidine to norpethidine and norpethidinic acid are increased. These metabolites are toxic and probably account for the lethargy and hypotension seen in one study. The effects of the phenothiazines on pethidine-induced respiratory depression may be related. Both the opioids and the phenothiazines are CNS depressants, and their effects may be additive. 

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