About drug interaction

It is important to know about drug interactions because of the increasing prevalence of using more than one drug at a time among people who present themselves for drug treatment. 

Pharmacists should be aware of the differences in safety standards and regulatory control between drugs and dietary supplements (Table 1). When counseling people about dietary products, pharmacists must be aware that the DSHEA allows the promotion of substances that may have variable potency, unidentified components, unproven efficacy, and unknown adverse effects. The DSHEA does not require warnings about drug interactions or medical conditions under which a dietary supplement should not be used. In view of the liberal labeling provisions of the DSHEA, pharmacists cannot trust dietary supplement company literature and should consult reliable information sources (Table 2)." ... 

For further information about drug interactions involving the QT interval see Drugs that prolong the QT interval + Other drugs that prolong the QT interval , p.257. 

The aim of Stockley s Drug Interactions is to inform busy doctors, pharmacists, surgeons, nurses and other healthcare professionals, of the facts about drug interactions, without their having to do the time-consuming literature searches and full assessment of the papers for themselves. These therefore are the practical questions which this book attempts to answer... 

Potential DDIs have been frequently reported, but only few studies have been conducted on actual interactions. Some data are available about drug interactions among elderly patients hospitalized for drug toxicity [76]. In a recent review [77], differences between actual and potential DDIs were outlined the incidence of actual DDIs resulted lower than that of potential DDIs important adverse effects occur only in the presence of specific risk factors, such as age or genetic polymorphisms. 

The search generated 436 articles, of which 47 articles were included in the study. Three articles provided results about drug interactions with real clinical consequences, 42 reported potential interactions and 2 described both. The prevalence of patients experiencing drug interactions was between 35% and 45%, and the number of interactions per 100 patients was between 37 and 106, depending on the group of studies analysed. There was a considerable increase in these rates in patients with heart disease and elderly persons. 

Figure 1 A flow chart of experimental information about drug-receptor interaction. The objects of experimental and theoretical investigation are boxed, and the experimental information is circled.

Many have a molecular mass of about 55 kDa Many are inducible, resulting in one cause of drug interactions... 

Inform the patient about the potential drug-drug interactions with warfarin, including over-the-counter medications and dietary supplements (Tables 7-8, 7-9, and 7-10). Instruct the patient to call the health care practitioner responsible for monitoring warfarin therapy before starting any new medications or dietary supplements. 

Evaluate for adverse effects and drug interactions. For patients on topical therapy, evaluate for local adverse effects. For patients on acetaminophen or NSAIDs, inquire about alcohol use. 

Pharmacodynamic studies deal more specifically with how the drug brings about its characteristic effects. Emphasis in such studies is often placed upon how a drug interacts with a cell/organ type, the effects and side effects it induces, and observed dose-response curves. 

Patients with acute gout should be monitored for symptomatic relief of joint pain as well as potential adverse effects and drug interactions related to drug therapy. The acute pain of an initial attack of gouty arthritis should begin to ease within about 8 hours of treatment initiation. Complete resolution of pain, erythema, and inflammation usually occurs within 48 to 72 hours. 

---