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The most important interaction and adverse events for narcotics have to do with sedating and depressant effects.
Absolutely most important will be the effects on the respiratory system. Narcotics will slow down the breathing response and if there is overdose or another drug taken with a similar depressant effect, the respiratory reflex will be inhibited and a persons breathing may slow to a stop.
This is by far the most serious adverse reaction and dru-drug interaction.
The therapeutic action of narcotics is not completely understood but is thought to be a blockage of receptor sites that control pain impulses. The most important indication is for pain control. This is almost exclusively the indication for use of narcotics.
Contraindications are primarily the use of other drugs that may cause a drug-drug interaction and a history of narcotics dependence or abuse.
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