additive effect with drugs such as the macrolide antibiotics (azithromycin, clarithromycin, and erythromycin) that prolong the QT interval. St. John’s wort St. John’s wort induces CYP3A4, causing decreased drug levels of interacting substrates (Dresser, Schwarz, Wilkinson, & Kim, 2003; Foster et al., 2003; Goey, Mooiman, Beijnen, Schellens, & Meijerman, 2013; Gurley et al., 2002; Henderson, Yue, Bergquist, Gerden, & Arlett, 2002; Izzo & Ernst, 2009; Kawaguchi et al., 2004; Komoroski et al., 2004; Markowitz et al., 2003; Patel, Buddha, Dey, Pal, & Mitra, 2004; Rahimi & Abdollahi, 2012; Smith, Lin, & Zheng, 2001). St. John’s wort also induces P-glycoprotein, which is a carrier mechanism responsible for transporting drugs and other substances across cell membranes. When P-glycoprotein is induced in the gastrointestinal tract, it can prevent the absorption of some medications such as doxycycline (Dürr et al., 2000; Hennessy et al., 2002; Kim, 2002; Rahimi & Abdollahi, 2012). In addition, induction of P-glycoprotein can decrease entry of drugs into the central nervous system (CNS) and decrease access to other sites of action.
increasing the risk of adverse effects (Ainslie et al., 2014; Charbit, Becquemont, Lepère, Peytavin, & Funck-Brentano, 2002; Fuhr et al., 2002; Jetter et al., 2002; Kanazawa, Ohkubo, & Sugawara, 2001; Lilja, Kivisto, & Neuvonen, 1998, 1999; Tanaka et al., 2013). Kava Concomitant use of kava and alcohol, barbiturates, benzodiazepines, or other CNS depressants can increase the risk of drowsiness and motor reflex depression (Abe, Kaye, Gritsenko, Urman, & Kaye, 2014; Meng & Liu, 2014; Munte, Heinze, Matzke, & Steitz, 1993; Pittler & Ernst, 2000). l-tryptophan Theoretically, concomitant use of l-tryptophan with medications that cause sedation may have additive effects, as l-tryptophan can cause fatigue and drowsiness (Lieberman, Corkin, & Spring, 1985; Robinson et al., 2014). Sida cordifolia Sida cordifolia contains the constituent ephedrine, which gets its name from another herb, ephedra (discussed in the preceding paragraph). Ephedrine has been linked to QT-interval prolongation (Konaté et al., 2012; McBride et al., 2004). Theoretically, Sida cordifolia might have an
HERBAL AND DRUG USE IN DENTAL PATIENTS WHO ARE PREGNANT OR BREASTFEEDING
Balancing the risks of the drug’s potential adverse effects (usually on the fetus) with the benefit (usually to the mother) of treating the disease is the goal when prescribing medication to a patient who is pregnant (Donaldson & Goodchild, 2012). This goal would also apply to herbal supplements. The U.S. Food and Drug Administration traditionally has classified drugs on the basis of the level of risk they pose to the fetus in order to determine the risks associated with the use of drugs in pregnancy (Table 9).
The dental patient who is pregnant represents two significant challenges to the dental professional. First, although most dental procedures are elective and can be postponed until after the baby is delivered, dental treatment for a pregnant woman who has oral pain, advanced disease, or infection should not be delayed. Second, not all women of childbearing age know that they may be pregnant, and when selecting and prescribing a medication for any woman of childbearing age, the clinician should always consider the possibility of her conceiving while she is still receiving the medication.
Table 9: U.S. Food and Drug Administration Pregnancy Risk Factor Definitions* Category Definition A The results of controlled studies in women fail to demonstrate a risk to the fetus in the first trimester (and there is no evidence of risk in later trimesters), and the possibility of fetal harm appears remote. B The results of controlled studies in women fail to demonstrate a risk to the fetus in the first trimester (and there is no evidence of risk in later trimesters), and the possibility of fetal harm appears remote. OR The results of animal reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the first trimester and there is no evidence of risk in later trimesters. C Either the results of studies in animals have revealed adverse effects (teratogenic, embryocidal, or other) on the fetus and there are no controlled studies in women. OR Results of studies in women and animals are not available; drug should be given only if the potential benefit justifies the potential risk to the fetus. D There is positive evidence of human fetal risk, but the benefits of use in pregnant women may be acceptable despite the risk (for example, if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective). X Results of studies in animals or humans have demonstrated fetal abnormalities or evidence of fetal risk based on human experience, or both, and the risk of the use of the drug in pregnant women clearly outweighs any possible benefit; use of the drug is contraindicated in women who are or may become pregnant. *Being phased out as of June 30, 2015. Note . From “Pregnancy and Medicines,” by the U.S. Department of Health and Human Services, 2010, retrieved from https://www. womenshealth.gov/publications/our-publications/fact-sheet/pregnancy-medicines.html
For many years the FDA used a lettering system to categorize risk (FDA, 2016). Drugs in categories A and B were considered safe for use, whereas drugs in category C were to be used only if the benefits outweighed the risks.
Drugs in category D were to be avoided except in certain exceptional circumstances (i.e., life-threatening condition to mother). The use of category X drugs in pregnant women was stringently proscribed. The categorization for
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