Med of the Month: Digoxin

Digoxin is a medication where small changes can have outsized consequences. Used to manage heart failure and atrial fibrillation, it has a narrow therapeutic index, which means the difference between a therapeutic dose and a toxic one can be relatively small.

That matters in dentistry because changes in kidney function, electrolytes, and interacting medications can all affect digoxin levels and toxicity risk. Several medications commonly prescribed in dental practice may interact with it, and epinephrine requires additional consideration. In other words, digoxin is one medication on the health history that deserves more than a passing glance.

Generic Name: Digoxin

Brand Name(s): Lanoxin®, Cardoxin®, Digitek®, Lanoxicaps®

Pronunciation: di JOX in

About digoxin:

• Digoxin is used to treat heart failure and atrial fibrillation.

• It should not be used in those who have had "sick sinus syndrome" or "AV block" without a pacemaker.

Dentistry-related tidbits:

If you're treating a patient taking digoxin, a few considerations are worth keeping in mind:

Local Anesthetic Warnings: 

• Speak with the patient's physician before using local anesthetics with epinephrine or a retraction cord containing epinephrine.

• Monitor heart rate when administering the following local anesthetics to a patient taking digoxin, as this combination may increase the risk of bradycardia:

  • Articaine (Septocaine, Ultracan, Ultacan Forte, Articadent Dental with Epinephrine, Orabloc)

  • Bupivacaine (Marcaine, Sensorcaine)

  • Lidocaine (Xylocaine, Ztlido)

  • Mepivacaine (Carbocaine, Polocaine)

  • Ropivacaine (Naropin)

• When administering epinephrine to a patient taking digoxin, exercise caution and monitor heart rate because the combination may increase cardiac irritability and the risk of arrhythmias. In adults, limit the Epinephrine dose to 0.04 mg or the following:

  • 1 cartridge of anesthetic containing 1:50,000 Epinephrine

  • 2 cartridges of anesthetic containing 1:100,000 Epinephrine

  • 4 cartridges of anesthetic containing 1:200,000 Epinephrine

Treatment Considerations:

• Speak with the patient's physician before beginning dental treatment beyond a prophylaxis and examination, prescribing medications, administering local anesthetics, or using a retraction cord containing epinephrine.

• Thrombocytopenia has been reported in rare instances.

Staying Safe: important interactions to be aware of

Using a tool like MedAssent DDS Rx Check can help support safe prescribing and identify clinically relevant interactions.

Some of the most clinically important interactions with digoxin include:

• Medications that may increase digoxin levels and the risk of bradycardia or AV block include:

  • Alprazolam

  • Macrolide antibiotics: Azithromycin, clarithromycin, erythromycin

    • Of these, azithromycin is the safest to use

  • Tetracycline antibiotics: Doxycycline, minocycline, tetracycline

  • Other antibiotics: Amoxicillin, trimethoprim, metronidazole

  • NSAIDs: Celecoxib, diclofenac (including topical), etodolac, fenoprofen, flurbiprofen, ibuprofen, ketorolac, naproxen

  • Antifungals: Itraconazole, ketoconazole

  • Tramadol

• Medications that may increase the risk of digoxin toxicity and cardiac arrhythmias include:

  • Amphotericin

  • Steroids: Betamethasone, cortisone, dexamethasone, hydrocortisone, prednisone, prednisolone, methylprednisolone (may also increase the risk of hypokalemia)

• Carbamazepine may decrease digoxin levels and effectiveness. The combination may also increase the risk of PR-interval prolongation, AV block, and bradycardia.

• Propofol in combination with digoxin may increase the risk of bradycardia.

Fun facts:

• Digoxin comes from foxglove. It is a cardiac glycoside derived from Digitalis lanata, also known as woolly foxglove. Medicinal use of digitalis preparations dates back centuries, with physician William Withering publishing his landmark account of foxglove for the treatment of “dropsy,” now recognized as edema associated with conditions such as heart failure, in 1785.

• Its therapeutic window is unusually narrow. Digoxin is considered a narrow therapeutic index drug, so relatively small changes in drug exposure can have meaningful clinical consequences. Age, kidney function, electrolyte abnormalities, body weight, and interacting medications can all affect the risk of toxicity.

• Digoxin toxicity can literally change the way a patient sees the world. In addition to nausea, vomiting, and cardiac arrhythmias, toxicity can cause blurred vision, halos, and characteristic disturbances in color vision, including a yellow-green tint.

• A prescription from the dental office can matter. Digoxin is a substrate of P-glycoprotein, and a variety of medications can alter its absorption or clearance. Some antibiotics and antifungals relevant to dental prescribing can substantially increase digoxin exposure, which is one reason reviewing the full medication list matters before reaching for the prescription pad.

Get more dental-specific drug information with the Digital Drug Handbook (web) or BrushUp Rx (mobile app).