Full Clinical Explanation of Ernest’s Medication Risk

“Ernest” Medication Risk mailer – 11/17

Ernest is on many medications, and he is at moderate risk for a medication-related problem. Overall, his medications are moderately sedating and may cause some cognitive impairment. Because four of these medications are competing for two metabolizing pathways, it is important that his pharmacist advise on time of day dosing, to ensure optimal efficacy and symptom control.

Ernest’s Medication List:

  • Spironolactone
  • Montelukast
  • Metoprolol
  • Lisinopril
  • Furosemide
  • Formoterol/budesonide
  • Clonidine
  • Bupropion
  • Atorvastatin

1. Medication Count
Ernest is receiving a total of 10 medications. Studies show that polypharmacy, the practice of administering numerous medications, has been shown to lead to increased adverse events, falls, and reduced adherence. Evaluate the continued need for duplicate therapy with diuretics including spironolactone and furosemide. What is the indication? If appropriate at this time, consider optimizing monotherapy with a single diuretic to reduce pharmacy burden, costs, and potential adverse effects. Blood pressure and potassium should be monitored with medication changes.

2. Sedative Burden
Ernest has a sedative burden of 7. Monitor and assess for daytime sedation. Higher sedative burdens are associated with lower objective physical function over time and frailty. Evaluate the continued use of sedating medications and ensure that the doses remain appropriate for his age and renal function.

Because of potential side effects, including reported drowsiness, clonidine may not be considered a drug of choice for this elderly participant. Determine what therapies to manage hypertension have been tried in the past. Evaluate the participant’s adherence to antihypertensives. If there is a history of nonadherence, discuss discontinuing multiple therapies. If possible, consider optimizing metoprolol, lisinopril, and furosemide, and using combination therapies when appropriate. A smaller medication burden comprised of tolerable medications may improve adherence and optimize blood pressure.

3. Competing medications
Four of his medications are competing for two metabolizing pathways. Both metoprolol and bupropion are metabolized by CYP2D6, and are taken at the same time of the day. Bupropion demonstrates a higher affinity for this metabolizing enzyme. Due to metoprolol’s weaker affinity, its metabolism is impeded by the co-administration of bupropion. Thus, we expect increased concentrations of metoprolol. Consider careful monitoring of blood pressure and heart rate. If the participant is experiencing adverse effects of metoprolol, the dose may be lowered or the two interacting medications separated.

Although atorvastatin, montelukast, and metoprolol are metabolized by CYP3A4, the effect of this multi-drug interaction is minimal. This is because CYP3A4 is not the major metabolic pathway for montelukast and metoprolol and thus, the effect is not likely to be clinically significant. Nonetheless, continue to monitor for side effects of all medications.

4. Drug-Drug Interactions
Spironolactone, lisinopril, and furosemide all affect potassium in the body. Potassium-sparing diuretics, such as spironolactone, enhance the hyperkalemic effect of lisinopril, and other angiotensin-converting enzyme inhibitions. On the contrary, furosemide, a loop diuretic, may deplete potassium stores. Thus, potassium level should be closely monitored to make sure that they remain at an appropriate level.