Case Studies
Case 1
CS, a 77-year-old man recently diagnosed with atrial fibrillation, presents to your pharmacy with a new prescription for dabigatran etexilate 150 mg twice daily. His past medical history is significant for hypertension and type 2 diabetes (and therefore has a CHADS2 score of 3). He is currently taking metoprolol, lisinopril, and metformin. Upon talking with CS you find out that he uses a pillbox to manage his medications.
As CS’s pharmacist, what important counseling point regarding his dabigatran should you offer?
Case 2
PH, a 33-year-old woman, presents to your healthcare clinic with a 10-year history of worsening plaque psoriasis currently affecting 15% of her body. The psoriatic plaques are found on both her trunk and extremities. She has tried a variety of topical steroids and a topical vitamin D analog as well as PUVA and NB-UVB phototherapy treatment in the last 3 years, none of which optimally controlled her psoriasis. She has a history of obesity and was recently diagnosed with hypertension for which olmesartan 20 mg daily was prescribed. Her physician asks for your input on which therapy PH should try next for her psoriasis.
How do you, the pharmacist, respond to PH’s physician?
ANSWERS
Case 1: Dabigatran etexilate is an orally administered prodrug that is converted to its active form, dabigatran. It is formulated as a capsule containing pellets with a tartaric acid core coated in the drug. This formulation is used to generate the acidic microenvironment required for optimal dissolution and absorption of dabigatran. There is potential for loss of potency due to moisture-induced medication degradation if the product is not stored in its original bottle (which has a desiccant) or blister packaging. In one study dabigatran etexilate capsules were openly stored for a single day at 40°C/75% humidity; and these conditions produced up to a 0.7% increase in degradation of the medication over the day. As CS’s pharmacist, it is important to counsel him to not place dabigatran in his pillbox; but rather, to keep it in its original packaging to ensure maximum stroke prevention benefit. If CS is concerned about forgetting to take his dabigatran, the pharmacist might suggest a different method for CS to remind himself, such as setting an alarm through a digital watch or cell phone or writing himself a note and placing it in or near his pillbox.
Case 2: Guidelines suggest that patients with widespread plaque psoriasis (>5% of body surface area) receive treatment with systemic non-biologic or biologic therapy or phototherapy. Since PH’s response to phototherapy was inadequate, her options at this time include biologic (adalimumab, infliximab, etanercept, and ustekinumab) and non-biologic (methotrexate, cyclosporine, and acitretin) agents. PH is of childbearing age, therefore biologics may be preferred because they are category B while methotrexate and acitretin are category X and cyclosporine is category C. In addition, cyclosporine carries a risk of hypertension which could adversely affect PH, who recently began treatment for hypertension. The 3 tumor necrosis factor inhibitors (adalimumab, infliximab, and etanercept) are equally recommended by national guidelines. Ustekinumab, an anti-IL-12/23 approved after these guidelines, has shown superior efficacy in achieving PASI-75 when compared to etanercept at 12 weeks with long term-efficacy demonstrated for responders for up to 3 years. If PH decides to initiate one of these biologic therapies, she should be sure her vaccinations are up to date since live vaccines will be contraindicated. PH should also receive a PPD test prior to therapy since the biologics carry the risk of tuberculosis and disease reactivation.
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