Question

Samuel is an 82-year-old male brought in by his daughter for complaints of low blood sugar. Samuel has a history of type II diabetes well-controlled with glyburide and diet. He was treated last week at an urgent care for a suspected staph infection to his arm with sulfamethoxazole and trimethoprim. He also takes lisinopril, Lipitor, Flomax, Paxil, Coenzyme Q10, and a multivitamin. His daughter also found old prescriptions for alprazolam, atenolol, and terazosin in his medicine cabinet.

1. With what you know about drug-drug interaction in older adults, what could be the cause of his hypoglycemia?

2. What questions do you need to ask the patient and his daughter about safe medication management?

3. What education should be offered to this patient and his family?

Answer 1

Drug-drug interactions : Drug-drug interactions (DDIs) represent an escalating concern for older adults attributed to polypharmacy, multi-morbidity and organ dysfunction.
A drug given to treat one disease can exacerbate another disease regardless of patient age, but such interactions are of special concern in older adults. Distinguishing often subtle adverse drug effects from the effects of disease is difficult (see table Drug-Disease Interactions of Concern in Older Adults) and may lead to a prescribing cascade.
Drug-drug interactions in older adults differ little from those in the general population. However, induction of cytochrome P-450 (CYP450) drug metabolism by certain drugs (eg, phenytoin, carbamazepine, rifampin) may be decreased in older adults
The change (increase) in drug metabolism may be less pronounced in older adults.
Many other drugs inhibit CYP450 metabolism and thus increase the risk of toxicity of drugs that depend on that pathway for elimination. Because older adults typically use a larger number of drugs, they are at greater risk of multiple, difficult-to-predict CYP450 interactions.
Also, concurrent use of ≥ 1 drug with similar adverse effects can increase risk or severity of adverse effects.
What could be the cause of his hypoglycemia?

Mr. Samuel is on glyburide and the drug will not interact with sulfamethoxazole(antibiotic), because this drug is a CYP2C9 inhibitor with unspecified potency. The interaction of these two drugs will cause hypoglycemia.

What questions do you need to ask the patient and his daughter about safe medication management?

Does the patient experienced similar problem yet before?
If so, how did you managed?
At what timings you are taking all these drugs?
Do you have any other associated symptoms other than low blood sugar?
Have you mentioned the name of the hypoglycemic agent to the physician you met last week for staph infection?
Are you keeping all these medications together?
Had you missed any of these drugs at anytime?
What you did immediately after hypoglycemia?
When you were diagnosed with diabetes mellitus?
From that time, are you on the same medication?
What education should be offered to this patient and his family?

1) Effectively Communicating Signs and Symptoms

Educate the patient and daughter regarding the receiving medications known to cause hypoglycemia, providing education regarding the associated signs and symptoms
the importance of follow-up testing, and the need for careful management and close medical supervision is imperative.
2) Patient education

MTM interactions
Comprehensive teaching of appropriate management strategies involving patients and their families and caregivers.