Prescribing in the Elderly

Open Handout

 


 
Cases for Residents

Case 1

 

Mr. P-R is a 90 y/o male with HTN, Type 2 DM, hyperlipidemia, peripheral neuropathy, visual impairment, hearing impairment and disequilibrium.  Although he no longer drives secondary to visual impairment, he is otherwise functionally independent, and enjoys reading, taking walks with his wife and his family.

He presents now with 3 falls in the past 4 weeks. He has no new symptoms – all of the falls involved “losing his balance.” He has not had syncope, and he fortunately has not suffered serious injury.  He otherwise feels well and has had no changes in his daily routine. He has had no symptoms of hypoglycemia

Medication list

Hctz 25 mg a day
Amlodipine 5 mg a day
Lisinopril 40 mg a day
Metoprolol 25 mg bid
Metformin XR 1 gm a day
Simvastatin 40 mg a day
ASA 81 mg a day

Vital signs

AF, R 16, Supine BP 120/70, P 68. Standing BP 100/60, P 72 (orthostasis new)

Has several bruises on his shins, but otherwise his exam shows a non-focal neuro exam, with no obvious change in his long-standing peripheral neuropathy. On “get-up and go” test he has normal muscle strength, and some gait unsteadiness.

Labs are remarkable for a Na+ of 125 (baseline 132), K+ 4.6, BUN 18, Cr 0.9, BS 147.


STOP READING HERE

 

  1. On an index card: Write the changes you recommend making in his medication list.
  2. Reader reads these changes
  3. Discuss medication list and changes using the CHAMP approach and in light of his recent falls.

 

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Case 1

Discussion

 

Mr. P-R presents with new onset of frequent falls. He has no evidence of new neurologic event. He has multiple reasons why he might fall – vision impairment, peripheral neuropathy and disequilibrium. New findings include orthostasis and hyponatremia.  All of his BP medications can contribute to orthostasis, and several can contribute to the development of hyponatremia. As both the hyponatremia and orthostasis increase his fall risk, one or more of the anti-hypertensives should be discontinued.


Cost and Compliance

His medications are all available in generic forms, most are on the $4 drug list at many pharmacies.

His wife has always monitored his medications and he rarely forgets to take them


Hazardous Interactions

There are several interactions here –

Amlodipine – Hctz

Amlodipine –  Lisinopril

Hctz – Lisinopril

Amlodipdine – Metoprolol

Lisinopril – Metoprolol

Hctz – Metoprolol

These interactions are all related to synergestic blood pressure lowering affects, and all of these medications can be prescribed safely together with appropriate monitoring

There is a theoretical risk of metoprolol masking signs of hypoglycemia in a patient on metformin.


Aging Pharmacology

HCTZ – Older adults are more susceptible to hctz-induced hyponatremia. HCTZ increases Na+ excretion at the level of the distal tubule

Lisinopril – ACE-I can cause SIADH, perhaps by increased levels of angiotensin-1 crossing the blood-brain barrier, leading to conversion to angiotension-2, which then acts on the pituitary to increase ADH release

Metoprolol – b-blockers can further blunt impaired baroreceptor reflexes in older adults. Older adults adrenergic receptors are also less responsive to b-blockade, so that b-blockers may be less effective anti-hypertensive agents in the elderly.

Metformin – Theoretical concern for lactic acidosis exists in older patients due to decline in renal function.


Medications to Avoid

None of these medications are contraindicated in the elderly


Medication Review

He is on multiple anti-hypertensives, and at least one should be discontinued due to his orthostasis.


Polypharmacy
more medication than is clinically indicated

The patient is now normotensive and orthostatic, suggesting that he no longer requires all of his blood pressure medication.

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Case 2

 

Mrs. CB is a 71 y/o woman with a h/o multiple sclerosis, htn, depression, breast ca, s/p mastectomy, ER+, and DVT.  She is wheel-chair bound secondary to her multiple sclerosis and lives in a nursing home. She has recent symptoms of urgency and dysuria. She has had no fever, and o/w feels at baseline. A nurse calls you (on call) on a Saturday with a report that the patient’s urine culture has grown E .coli sensitive only to trimethoprim/sulfamethoxazole, ciprofloxacin and amikacin. She is afebrile and her vital signs are normal.


Medication list

Interferon sub-q weekly
Femara 5 mg q day
Coumadin 4 mg a day
Lisinopril 20 mg a day
Hctz 25 mg a day
Celexa 10 mg a day

 

STOP READING HERE

 

  1. On an index card: Write any additional information you would like to have, and what you recommend prescribing.
  2. Reader reads the answers on the cards
  3. Discuss potential interactions and what can be done to minimize the risk of these interactions. Include the antibiotics discussed.

 

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Case 2

Discussion

 

The on-call resident, the nurse and the patient are now stuck between the proverbial “rock and a hard place.” The patient has a symptomatic UTI, and the only oral medications both interact with Coumadin. The aminoglycoside, which can be given daily for uncomplicated UTI, must be given by injection. Important information that must be known before a well-informed decision can be made include the patient’s weight and creatinine (or the most recent creatinine clearance), and the patient’s INR.
The patient’s INR is 2.6, her Cr is 1.8, and her weight is 74 kg.

What is her estimated creatinine clearance?
Important interactions to consider include –

  • Sulfamethoxazole and Coumadin. Sulfamethoxazole interferes with the hepatic metabolism of the s-isomer of Coumadin. This is the most active form of Coumadin. On average, sulfa will produce the greatest rise in INR of any antibiotic, and should be avoided.
  • Ciprofloxacin also interferes with the metabolism of Coumadin, through a variety of medications, including affect on gut flora and inhibition of metabolism. The affect on INR is more variable, and while ciprofloxacin and other quinolones should be avoided, if possible, cipro can be given with either reduction of the coumadin dose and/or close monitoring of the INR.

The safest choice for this patient is amikacin, which can be given once daily in this patient due to her creatinine clearance.

This patient was actually seen in the emergency room and placed on bactrim. Several days later she developed a severe headache. She was found to have a sub-dural hemorrhage, and an INR of 7.5. She underwent craniotomy with removal of a portion of her parietal bone for decompression.

Always check for potential interactions when prescribing a medication for a patient on Coumadin.

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Case 3

 

Mr.  W is an 85 y/o man with a h/o CAD, CHF, HTN and a fib admitted for chest pain and CHF exacerbation. He is felt to have ischemia secondary to strain related to his CHF. He is placed on his home medications and his lasix dose is increased.  You are called on night float on his second hospital day because he has become hypotensive. He denies chest pain, and his shortness of breath is better than it was on admission.

VS: P 56, R18, BP 85/40, T 36.7. The patients lungs are clear, and he has no JVD or HJR. He does not appear acutely ill. His EGK is without change from admission, and shows no evidence of acute ischemia.


Medication list

Metoprolol 50 mg BID
Lisinopril 20 mg BID
Verapamil SR 120 mg BID
Warfarin 5 mg q day
KCL 10 meq q day
ASA 81 mg a day
Isosorbide dinitirate, 20 mg tid
Lasix 60 mg BID (home dose 20 mg bid).


Afternoon labs

INR 4.5, BUN 24, CR 1.2 (baseline 1 to 1.3), hgb 13.8

 

STOP READING

 

  1. On an index card, write your differential for the patient’s hypotension and elevated INR.
  2. Reader reads answers
  3. As a group, apply the CHAMP approach to this patient’s medication list and discuss.

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Case 3

Discussion

 

The patient presents with hypotension during treatment for a congestive heart failure exacerbation. The absence of chest pain and an EKG without acute changes lowers the likelihood that ischemia is the cause. The absence of fever and generally well appearance makes sepsis less likely. The elevated INR should raise suspicion for hemorrhage, and this needs to be considered, despite the recent normal Hgb. The absence of dyspnea and well appearance, and his anticoagulation status makes a PE less likely. While overdiuresis needs to be a consideration in this setting, the relatively normal BUN/Cr ratio coupled with baseline creatinine lowers the likelihood that this is the culprit.

This patient’s hypotension was due to “compliance.” At home he was not able to manage this fairly complicated drug regimen, and thus did not take his medications as prescribed. In the hospital he was prescribed his medication list, without reviewing it carefully with him. Since he was now being given all of his medications, he suffered an adverse drug event.

The goal now is to streamline his medication regimen, using as simple and effective a regimen as possible.


Cost and Compliance

This regimen is comprised of generically available drugs, and could be purchased for less than $50/month. Compliance is obviously an issue.


Hazardous Interactions

Verapamil – metoprolol – bradycardia, heart block

b-blockers and nitrates – hypotension

Asa and warfarin—increased risk of bleeding;

enalapril and k+  – hyperkalemia

Drug-disease interaction –verapamil and CHF – increased mortality in CHF


Aging pharmacology

Pharmacodynamics

Verapamil—increased receptor sensitivity leads to more constipation and a greater HR response

Coumadin – increased receptor sensitivity to Coumadin

Pharmacokinetics

Verapimil is a high first-pass clearance drug, and decreased clearance in aging

 

Medications to avoid

Avoid aspirin with anticoagulants

Avoid verapamil in patients with CHF and constipation

 

Polypharmacy

The patient is on several medications that may not be needed or whose risk exceeds the benefits. Consider tapering/discontinuing verapamil, aspirin and isosorbide.

 

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Case 4

 

Mr. RW is a 90 y/o man with moderate Alzheimer’s dementia, dysphagia, CKD (baseline Cr = 3.0), agitation and gout, admitted with nausea and vomiting, refusing food and drink. He is afebrile, his vital signs are normal, and he has a benign abdominal exam. Lab work is within normal limits, apart from an elevated BUN/CR.

He lives with his wife, who is his primary caregiver. She is 86 y/o and in poor health.

At baseline, he is able to ambulate and feed himself, but needs help with bathing, dressing and toileting.


Medication list

Exelon, 6 mg BID
Triamterene/HCTZ 37.5/25 daily
Seroquel  25 mg daily
Levothyroxine 50 mcg a day
Trazodone, 50 mg a day
Alprazolam, 0.25 mg qhs
Colchicine, 0.6 mg a day
Tolterodine, 0.4 mg a day

 

STOP READING

 

  1. On a note card, write down medications you would stop
  2. Read these aloud
  3. As a group, discuss this patient’s medication list using the CHAMP approach.
  4. Could any of his medications cause his nausea and vomiting?

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Case 4

Discussion

 

This patient’s nausea and vomiting could be secondary to Exelon (common side effect), or colchicine (particularly if he is taking this incorrectly).


Cost and Compliance

Exelon and seroquel are both expensive medications.

How is he taking the medication? Who is monitoring medication adherence?


Hazardous Interactions

Seroquel – Trazodone – Xanax:  increased risk of sedation, psychomotor impairment (synergestic effects)

Exelon-tolterodine: Exelon is pro-cholinergic; tolterodine is anti-cholinergic. These two drugs have antagonistic effects, and Exelon will likely decrease effectiveness of tolterodine.

Disease-Drug interactions:

Thiazide diuretics – gout: thiazides increase uric acid and risk of gout attack

Benzodiazapine – dementia: increase risk of falls

Seroquel and dementia – increased risk of death in patients with dementia taking antipsychotices.


Aging pharmacology

Pharmacodynamics

Benzodiazepine—increased receptor sensitivity leads to more CNS side effects

Pharmacokinetics

Xanax is fat-soluble, older patients have lower lean body mass – volume of distribution increased, leading to longer t ½

Xanax is metabolized by hepatic oxidative pathway, which is decreased in elderly, and has active metabolites, leading to prolonged t ½.

 

Medications to avoid

Avoid benzodiazapines in patients with dementia (falls, confusion)

Avoid thiazides in patients with gout

Avoid colchicine in patients with significant CKD


Polypharmacy

Patient is on several medications that interact with underlying diseases, or with each other, or may synergistically cause CNS side effects, or may not be effective.

His triamterne/hctz should be discontinued, and another BP medication substituted. This may, in itself, decrease risk of gout enough to stop his colchicine.

His alprazolam should be stopped, as well. An effort should be made to stop his trazodone – its effectiveness in agitation is not proven.

His tolteridone should also be discontinued, with monitoring for recurrence of GU symptoms.

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Case 5

 

Mr. EW is a 77 y/o male with h/o HTN, CAD s/p CABG and CKD, stage 3, BPH and hyperlipidemia. His wife brings him in because of concern for several weeks of trouble swallowing, decreased oral intake, trouble urinating and fatigue. About 3 weeks ago had developed nasal congestion and a cough. He was seen at an urgen care center, and placed on moxifloxacin (completed 5 days ago), diphenhydramine and pseudoephedrine.

On exam he is afebrile, with BP 115/72, P 74, R 16, T 36.8. He has lost 2 kg since last visit 4 weeks ago. His exam is o/w unremarkable, and he has a non-focal neuro exam.


Medication List

Lisinopril 20 mg a day
Lopressor 50 mg BID
ASA 81 mg a day
Simvastatin 40 mg a day
Diphenhydramine, 25 mg qid
Pseudoephedrine, 30 mg tid
Guiafenisin prn.

 

STOP READING

 

  1. Write, on a notecard, your differential diagnosis
  2. Reader reads cards
  3. Analyze medication list using CHAMP and discuss as a group.

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Case 5

Discussion

 

The patient has the subacute onset of trouble swallowing and decreased oral intake after being treated for what was likely a viral URI. In this setting, the most likely etiology of these symptoms is an ADR/ADE, likely secondary to diphenhydramine and pseudophedrine.  Other possibilities include an esophageal web or stricture, GERD, oropharyngeal muscle dysfunction, or a degenerative neurologic disease.

 

Cost and Compliance

This is a fairly inexpensive medical regimen.

Need to ascertain how he is taking medications.


Hazardous Interaction

Drug-Drug Interaction

Lisinopril-metoprolol: Increased blood pressure lowering through synergestic effects.

Pseudoephedrine – lisinopril/metoprolol – antagonistic effects. Pseudoephedrine may lessen anti-hypertensive effectiveness.

Drug-Disease Interaction

Pseudoephedrine-BPH: pseudoephedrine, as an a-agonist, may lead to increased difficulty urinating or urinary retention in men with BPH.


Aging pharmacology

Pharmacodynamics

Diphenhydramine: Increased receptor sensitivity, enhanced anticholinergic profile.


Medications to avoid

Diphenhydramine


Polypharmacy

On more than 5 meds. Several may not be needed any longer. No clear indication now for diphenhydramine and pseudoephedine.