1.1. Drug Interactions
Definition
In brief explanation, it is the effect of one drug altered by another drug due to concurrent or concomitant administration of two or more drugs known as “drug interactions”. It can also be defined as the modification of pharmacological activity of one drug by concomitant or concurrent administration of two or more drug is known as “drug interactions”.
DDIs occur when the effect of one drug is changed by the presence of another drug. The outcome can be harmful if the DDI causes an increased toxicity of the drug .However, a reduction in therapeutic efficacy due to a DDI may be just as harmful as an increase, others can be beneficial and valuable, DDIs are rare and therefore we use the expression …show more content…
The outcome of a drug interaction may be harmful if the interaction results in increased efficacy or toxicity of one or more drugs. However, reduction in efficacy due to a drug interaction can sometimes be just as harmful.[1,2] The clinical importance of drug interactions is evident when one considers that up to 8% of hospital admissions are due to adverse drug reactions and over 20% of these are due to drug interactions{.3} The incidence of drug interactions is difficult to quantify as this may depend on the “clinical significance” of the interaction.{1 }However the greater the number of drugs taken surely increases the risk of a drug interaction …show more content…
where a small margin exists between therapeutic and toxic drug levels.
B) High risk patients. The patient characteristic which has the most attitudes on drug interactions is age. Certain patient groups e.g. the elderly may have an increased risk of suffering a clinically significant drug interaction due to poly-pharmacy. It is likely that for patients taking 2-5 drugs daily the incidence of a potential drug interaction is 19%. This rises to over 80% for those taking 6 or more drugs.{5} Renal or in particular, hepatic impairment, either age-related or otherwise may affect the ability to metabolize drugs. [4,6,7] Patients with severe underlying disease may be less tolerant of changes in plasma concentration of their therapy.{4 }The disease being treated and any concomitant diseases may also influence drug interactions as can the patients pre-existing clinical