Question

FSR is an 81-year-old man (103.65kg, 66.5 in) with hypertension, diabetes mellitus, anemia, kidney failure and gastroesophageal reflux. FSR uses Apixaban 5mg bid for DVT recurrence (2014, 2018). Other medicines include: Pantoprazole, Ferrous Sulfate, Insulin NPH, Lisinopril/HCTZ and Gabapentin. In November 2018, he was evaluated by his primary physician for a fungus on the right foot, classified as severe and refractory to topical antifungal treatment. She was consulted at the infectious clinic for the treatment of the fungus in view of her diabetes mellitus condition. The service infectologist recommended the use of oral therapy with Itraconazole 200mg bid for one week.

What are the drug-drug interactions present, if any?

Is any adjustment required in FSR drug therapy?

Answer 1

There are many drug to drug interactions present in the above scenario. The drugs and their interactions with each other are listed below:

* Itraconazole and pantoprazole

Taking pantop with itraconazole can reduce the absorption of itraconazole and making it less effective in treatment of fungal infections.

* Apixaban and itraconazole

Taking itraconazole with Apixaban can increase the risk of bleeding.

* Hydrochlorothiazide (HCTZ) and insulin NPH

Taking HCTZ can increase your blood sugar levels and reduces the effectiveness of insulin.

* Lisinopril and Insulin NPH

Taking Lisinopril along with insulin NPH can lower the blood sugar levels and can cause hypoglycemia.

Some adjustments are required in FSR's drug therapy:

- While taking itraconazole and pantoprazole, itraconazole can be taken with some acidic beverages like cola. So that it doesn't reduces the effectiveness of itraconazole.

- Advice him to take Apixaban at lower dose ie, 2.5 mg twice a day so that the risk of bleeding can be reduced due to it's interaction with itraconazole.

- Frequent monitoring of blood sugar levels should be done.

- While taking HCTZ and insulin, insulin dosage should be increased thereby it helps in managing the blood sugar levels.