Hands OnAvoiding drug-drug interactions
Section snippets
Background
With the aging of the population and the development of effective agents to manage medical conditions, the risk for adverse drug interactions has increased. As a result, general dental practitioners (GDPs) must be aware of the medical conditions of their patients and the drugs they are taking so that dental agents can be used judiciously to avoid dangerous interactions. The types of drug interactions that can occur and common medical conditions being managed with drugs that the dental
Drug Interaction Types
The broad classes of drug interactions are pharmacodynamic and pharmacokinetic. In pharmacodynamic interactions, the pharmacological effect is modified without altering its concentration in tissue fluid. These interactions can produce antagonistic, additive, or enhanced effects. In antagonistic effects, the two drugs have opposing pharmacological effects and the result is a reduced effectiveness of one or both drugs. In additive effects, there may be an excessive response of the target tissue
Hypertension
For patients with hypertension, antihypertensive medications include thiazides and loop diuretics, calcium channel blockers (CCBs), angiotensin-converting enzyme (ACE) inhibitors, α- and β-adrenoreceptor-blocking drugs, and angiotensin II receptor antagonists. Often these are combined to achieve control of hypertension. The dental agents most likely to interact in hypertensive patients are adrenaline, which can produce a potentially dangerous increase in heart rate, peripheral vasoconstriction,
Hypercholesterolemia
Simvastatin is a lipid-lowering agent used to treat hypercholesterolemia. Any drug that inhibits the liver enzyme CYP3A4 risks increasing statin concentrations in the serum, with the attending adverse effects. Rhabdomyolysis, a form of myopathy, can develop, although the incidence of statin-related myopathy is low.
Macrolide antibiotics and azole antifungals are often prescribed by general dentists and have the potential for potentially harmful interactions with statins (Table 3). The
Cardiovascular Disease
Medications commonly used for cardiovascular diseases include aspirin, clopidogrel, and warfarin, which can be given alone or in combinations. NSAIDs can antagonize the antiplatelet effect of aspirin, since they compete for the same binding site. Clopidogrel interacts significantly with NSAIDs, resulting in increased bleeding. The antiplatelet effect of clopidogrel may be antagonized by macrolides and azole antifungals, causing reduced efficacy for this agent. Warfarin is associated with
Depression
The agents used to manage depression include selective 5-hydroxytryptamine reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs). Patients taking TCAs who are given lidocaine containing adrenaline are at increased risk of hypertension and arrhythmias. Using adrenaline-containing anesthetics could significantly affect the cardiovascular system, causing cardiac arrhythmias and hypertension. Local anesthetics can also initiate potentiation of the cardiovascular effects of TCAs.
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Dawoud BES, Roberts A, Yates JM: Drug interactions in general dental practice – considerations for the dental practitioner. Br Dent J 216:15-23, 2014
Reprints available from B Dawoud, Dental Foundation Trainee, 228-230 Ash Dental Practice, Manchester, Eccles, M30 0PF; e-mail: [email protected]