1. PRN Medications Indications & Use Bindu Swaroop, MD
Fundamentals of Medicine
July 2015

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 Pain Sleep Cardiovascular: Hypertension
Sedatives: ETOH withdrawal, agitation
Pulmonary: Nebulizers, Mucolytics
GI: Bowels, Heartburn, Constipation

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 bpm
Start with case vignette based on real admission at the Long Beach VA.
AVNRT= av nodal re-entry tachycardia

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
Problems with the orders: albuterol will worsen tachycardia, acetaminophen order is higher than recommended allowance for 24hrs, and ibuprofen should not be used in setting of hematemesis

6. Case Vignette Are these appropriate meds to give to the patient?
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?
Again- no ibuprofen in pt with hematemesis; in addition think about alternative analgesics before jumping to IV narcotics. Think about degree of pain, etiology and start with non-opiates and oral prior to IV if possible.

7. Analgesics Non-Opiods Opiods Oral Pain Severity SC/IM/IV
Adverse Effects
Non-Opiods
Acetaminophen mg
Mild
Ketorolac
30-60mg
Moderate
Caution in hepatic or renal impairment
Ibuprofen mg
PUD, GI bleed, renal toxicity
Opiods
Tramadol
50-100mg
Mild to Moderate
Tylenol w/ codeine
30mg-60mg/300mg
Morphine
Moderate to Severe
Constipation, Ileus, n/v, respiratory depression, urinary retention
Vicodin
(5mg/300mg)
Norco
(10mg/325mg)
Dilaudid
Severe
Caution Hepatic or Renal Impairment
Percocet
(5mg/325mg)
Fentanyl
I print this out and give it to the team.

8. Think about the analgesic ladder and use based on patient’s pain scale and etiology of pain.

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/ 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?
#3: pt is in withdrawal, likely causing the hypertension; also may have continued pain contributing to elevated BP
#4: could precipitate ischemic event such as MI or stroke
#5: use ativan for withdrawal or analgesics for pain

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
Emphasize that in cases where there is an unexpected elevation of BP, the etiology needs to be determined as per above list.

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 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
There is really NO indication for acute reduction in BP unless patient meets one of the above criteria.

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
Emphasize that there is rarely a need for acute reduction in the middle of the night for BP unless hypertensive urgency or emergency is present. In addition, there is no indication for IV medication unless patient is NPO or there is hypertensive emergency present.

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?
#7: benadryl is an anti-cholinergic, can lead to urinary retention. In addition an adverse effect of morphine is urinary retention.
#8: alternatives: ambien (zolpidem). See next slide of alternatives.

15. Hypnotics Benadryl 25mg-50mg Beers high severity Temazepam (Restoril)
Anti-cholinergic effects (confusion, dry mouth, urinary retention, wheezing; caution in pts with glaucoma and BPH
Temazepam (Restoril)
15-30mg
(geriatric 7.5mg)
Same AE as any benzo; contraindicated in glaucoma
caution in those with falls risk, hepatic or renal impairment
Trazodone (unlabeled use)
25-50mg
Okay in elderly
Hypotension, increased bleeding risk if on NSAID’s or warfarin, priapism, serotonin syndrome, caution post-MI or with h/o seizures
Zolpidem (Ambien)
5-10mg
Okay in elderly (avoid chronic use >90 days)
HA, dizziness, caution in those with respiratory compromise, myasthenia gravis

16. What could be contributing to the fall and gait impairment?
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?
#9: continued use of benzodiazepines in this patient.

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?
#10: albuterol nebs were prescribed on admission. Likely contributing to the tachycardia.

19. 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 bpm
Start with case vignette based on real admission at the Long Beach VA.
AVNRT= av nodal re-entry tachycardia

20. 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
Problems with the orders: albuterol will worsen tachycardia, acetaminophen order is higher than recommended allowance for 24hrs, and ibuprofen should not be used in setting of hematemesis

21. Pulmonary Nebulizers: Mucolytics:
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 minutes after bronchodilator administration
We often think of these medications as “benign” but it is important to be aware there are side effects that need to be monitored

22. Is this an appropriate order?
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?
#11: No, unless c.diff is ruled out you should not use anti-diarrheal agents. In addition lomotil has anti-cholinergic activity which could worsen his urinary retention.

23. 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. diff colitis
Loperamide (Immodium): caution in hepatic impairment
Lomotil (diphenoxylate/atropine): anti-cholinergic side effects)

24. Are these appropriate orders?
Case Vignette
The patient subsequently does well and is discharged. Upon discharging the patient, you order the following outpatient medication regimen:
Ibuprofen 600mg po tid prn
Norco 2 tabs q6hr prn
Combivent inhaler q4hr prn
Benadryl 25mg po qhs prn
Librium taper
Are these appropriate orders?
Not appropriate orders: ibuprofen should not be used given h/o hematemesis, total amount of vicodin should be <2g/day if he has liver disease; combivent should not be more frequent than q6h particularly with his history of tachycardia; no benadryl given anti-cholinergic side effects; benzos should be discontinued given his lethargy and altered mental status.

25. Convert frequently administered PRN meds into standing orders
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
Emphasize that prn orders should NOT be used to avoid night float from being called; they still need to assess the patient and determine the etiology of the acute problem. If patient is requiring frequent use of a prn order, then convert it to a standing order or long acting medication (such as anti-hypertensive, analgesics, etc)