1. Medication Interactions Elizabeth Rash PhD, ARNP, FNP-C UCF College of Nursing CFP Physicians Group

2. Medication Interactions Good and Bad – Synergism Ex. Codeine + acetaminophen or ibuprofen = increased pain relief – Adverse drug events (ADEs) A B Unidirectional A B Bidirectional

3. Adverse Drug Events (ADEs) The numbers (U.S. Prescribing 2003) 3.4 billion Rx filled – 10.1 million/yr for <65y – 23.5 million/yr for >65y

4. Adverse Drug Events (ADEs) 701,547 patients treated for ADEs in EDs (2004-2005) – 116,318 hospitalized – 1/3 2 o allergic reactions – 1/3 2 o unintentional overdose – 2/3 rd s considered to be potentially preventable

5. Adverse Drug Events (ADEs) Most ADEs 2 o 5 classes of drugs: – Insulins – Opioids (narcotics) – Anticoagulants – Amoxicillin containing antibiotics – Antihistamine containing cold products JAMA 2006

6. Adverse Drug Events (ADEs) 21.3% > 65yr (community dwelling) at least 1 inappropriate Rx drug 23% of nursing home admissions due to medication problems (J. Am. Pharm. Assoc.:Nov 2002)

7. Polypharmacy vs. Polymedicine

8. Drug Interactions: What? Other drugs – Coumadin® and Erythromycin increase bleeding Food – Grapefruit and Verapamil increase toxicity Herbs and supplements – St. John’s Wort and Zoloft® increase serotonin crisis risk Other medical conditions or diseases – Prednisone® and Diabetes increase blood sugar

9. Drug Interactions: How? Absorption – Can slow down or speed up how rapidly the drug gets into the blood stream Ex. antacids + tetracycline

10. Drug Interactions: How? Meta bolism enzymes – Inducers: speed the metabolism of another drug and can cause ineffectiveness – Inhibitors: slow the metabolism of another drug and can cause toxicity or ineffectiveness Plavix® and PPIs (Prilosec®) – PPI inhibits the action of Plavix® a Prodrug that does not work until it Is metabolized

11. Drug Interactions: How? Receptors – Some drugs block the tissue receptors that stop other drugs or chemicals from having action on that tissue Could be good or bad – Ex. Antihistamines (Claritin®) block allergens on the histamine receptors stopping allergic reactions – Ex. Antihistamines (Ditropan®) block the cholinergic receptors and interfere with Alzheimer’s drugs like Aricept from working 

12. Drug Interactions: How? Elimination – Taking an aspirin (acidic pH) with Zegerid® (basic pH) may cause more rapid elimination of the aspirin and decrease its effect

13. Drug Interactions: How? Timing – NSAIDs (Motrin®) interfere with the platelet benefits of a preventive Aspirin. If taking both, take the aspirin first and wait at least 2 hours before taking the Motrin®

14. Common Drug Interactions Antifungal drugs that end in "-azole”, Itraconazole or Sporanox®) Some antibiotics (end in "-mycin” Erythromycin®) Antacids cimetidine (Tagamet®) Drugs that prevent convulsions, (Dilantin® and Tegretol®). Cholesterol drugs such as statins (Lipitor®) Blood thinning drugs (Coumadin®)

15. Drug Interactions: Preventing ADEs Brown bag or drug list to all providers ID bracelets Use 1 pharmacy Pharmacist consultation Communicate side effects and don’t stop abruptly without discussing with provider Follow instructions

16. Questions? Thank you! CFP Physicians Group 985 SR 436 Casselberry Fl 32707 (407) 831-5252 http://cfpphysiciansgroup.com/