PRN Medications

1. PRN Medications Bindu Swaroop, MD Fundamentals of Medicine July 2014 Indications & Use

2. Objectives • Identify which prn medications are appropriate for inclusion in admission orders • Identify contraindications and adverse effects associated with common prn medications • Known when to evaluate the patient prior to ordering or the nurse giving a prn medication

3. Common Uses • Sleep • Pain • Cardiovascular: Hypertension • Sedatives: ETOH withdrawal, agitation • Pulmonary: Nebulizers, Mucolytics • GI: Bowels, Heartburn

4. Case Vignette • HPI: 59 year old male admitted for chest pain and acute ETOH intoxication. He also complains of hematemesis during his most recent drinking binge. • PMHx: AVNRT, Hepatitis C, insomnia, depression, COPD • Meds: combivent inhaler bid, ibuprofen 600mg po tid prn • EKG on admission reveals AVNRT @111 bpm

5. Case Vignette • He is admitted to the medicine service with the following prn orders: • -Ativan 2mg IV q4hr prn withdrawal • -Albuterol neb q6h prn, Atrovent neb q6hr prn • -Acetaminophen 650mg q4hr prn pain • -Ibuprofen 600mg po tid prn pain

6. Case Vignette • That night the patient subsequently requests pain medication for his chest pain. It is determined by the night float that there is no evidence of ACS. Since ibuprofen is ordered prn the night float instructs the nurse to give this to the patient. The patient still complains of pain later that night, and the night float writes an order for Morphine sulfate 2mg IVP q4hr prn pain. • Are these appropriate meds to give to the patient? • What other alternatives could have been given?

7. Analgesics

9. Case Vignette • The next day his BP has risen to 170/105. He is given hydralazine • 10mg IVP by the team with a drop in his BP to 125/78. • 3. What is likely contributing to the rise in BP? • 4. What side effects could occur from lowering the BP too much? • 5. How else could this patient have been treated?

10. Hypertension Goal: • -To identify and treat the underlying cause • -Prevent end-organ damage Common Causes: • Rebound • Inadequate dosing • Drug Interactions • ETOH withdrawal • Hypoxemia, respiratory distress • Pain, Anxiety • Autonomic response: urinary retention, constipation, SCI

11. Hypertension • Approach to evaluating the patient: • -Determine patient’s baseline • -Confirm accuracy, both arms, cuff size • -Screen for the underlying cause • -Determine if hypertensive emergency or urgency is present

12. Hypertension Treatment • Hypertensive Urgency • -SBP >180 or DBP >120 • -gradual reduction of BP to 160/110 over 24-48 hours • -use ORAL meds • Hypertensive Emergency • -evidence of end-organ damage -Immediate reduction of SBP by 15-20% -Use PARENTERAL agents and transfer to ICU

13. Hypertension Clinical Pearls • Hypertensive treatment rarely requires immediate treatment in the middle of the night • Avoid prn use of rapid acting agents (can precipitate ischemic events) • For patients with sustained HTN, primary team should initiate treatment with long acting regimen

14. Case Vignette • Later that night the patient requests something for sleep and receives Benadryl 25mg po, written as qhs prn per night float. On day three of admission he develops urinary retention with a PVR of 300cc. A foley catheter is placed. You review his chart and notice a prior urology note indicating the patients prostate size on DRE is 50g. • What could be contributing to the urinary retention? • What other alternatives could have been used for his insomnia?

15. Hypnotics

16. Case Vignette • He remains hospitalized due to social issues including homelessness. On day 4 of admission you are called by the nurse due to the patient falling in his room. You evaluate his gait and notice he is unsteady in addition to being more somnolent than usual. • What could be contributing to the fall and gait impairment?

17. Sedatives • Ativan: common use in ETOH withdrawal • -AE include sedation, respiratory depression • -Caution in those with acute angle glaucoma, sleep apnea, respiratory issues, hepatic/renal impairment, h/o drug abuse or falls risk • Anti-Psychotics: Typical (Haldol) & Atypical (Seroquel, Risperidone) • -anti-cholinergic side effects, QT prolongation • -careful in dementia related psychosis (increased risk of death compared to placebo)

18. Case Vignette A review indicates the patient has continued to receive Ativan despite no further evidence of withdrawal due to complaints of anxiety and insomnia. A review of his chart reveals he was previously on mirtazapine but this medication had not been continued on admission. During rounds, it is noted that the tachycardia noted on admission is persistent. What else could be contributing to the tachycardia?

19. Pulmonary • Nebulizers: • Albuterol (max dose 3mL q4hours): can cause tachycardia, arrhythmia, caution in patients with ischemia • Atrovent: anti-cholinergic side effects; caution in those with glaucoma, BPH • Mucolytics: • Mucomyst: can cause bronchospasm; use 10-20 minutes after bronchodilator administration

20. Case Vignette • The patient subsequently complains of diarrhea the next day. Stool studies are sent, and the intern orders lomotil prn for loose stools. • Is this an appropriate order?

21. Gastrointestinal Heartburn: Maalox (aluminum dioxide, magnesium hydroxide) or Maalox plus AE: constipation, cramps, fecal discoloration; aluminum intoxication • Use with caution in renal impairment: hypophosphatemia or hypermagnesemia • long list of drug interactions • Must be administered one hour apart from other oral meds Constipation: phosphate (fleets) enema • Do not use in patients with renal impairment, ascites, heart failure, GI obstruction or megacolon Diarrhea: do not use in those with c.difficile colitis • Loperamide (Immodium): caution in hepatic impairment • Lomotil (diphenoxylate/atropine): anti-cholinergic side effects)

22. Case Vignette The patient subsequently does well and is discharged. Upon discharging the patient, you order the following outpatient medication regimen: • Ibuprofen 600mg potid prn • Vicodin 2 tabs q6hr prn • Combivent inhaler q4hr prn • Benadryl 25mg poqhs prn • Librium taper Are these appropriate orders?

23. Summary • For all PRN orders, know the correct dosage, common adverse effects and contraindications • Check the next day to see if your patient actually received any of the PRN meds • Convert frequently administered PRN meds into standing orders • Don’t just put in PRN orders to save night float the “trouble” of getting called • Evaluate underlying cause or condition requiring use of a PRN med and treat accordingly