Conscious sedation: Pharmacology.
Pharmacokinetics and pharmacodynamics.
(2) Co-administration

ADVANCED

The differences in the pharmacokinetic and pharmacodynamic effects when sedation drugs are co-administered.

When sedation drugs are co-administered, there can be differences in the pharmacokinetic and pharmacodynamic effects compared to when they are administered alone. These differences are due to interactions between the drugs at various points in the pharmacokinetic or pharmacodynamic pathway.

If a sedative drug is metabolised by the same enzyme as another drug that the patient is taking, the co-administration of these drugs can lead to altered metabolism of one or both drugs, changing in their pharmacokinetic effects. Similarly, co-administration of drugs that compete for protein binding sites in the bloodstream can also alter the pharmacokinetics of the drugs.

Co-administration of sedative drugs that act on the same receptors in the brain can result in additive or synergistic effects, increasing the sedative effect beyond what would be expected if the drugs were administered alone. Conversely, co-administration of drugs with opposing pharmacodynamic effects can result in decreased efficacy or even cancel out the effects of one or both drugs.

The specific effects of co-administered sedative drugs will depend on various factors, including the specific drugs being administered, the doses and rates of administration, and the patient's individual pharmacokinetic and pharmacodynamic profile. It is important to consider potential drug interactions when administering sedative drugs in order to minimise the risk of adverse effects and optimise sedative efficacy. This may involve adjusting the dose or rate of administration of one or both drugs, or considering alternative sedative drugs or routes of administration.