Foscarnet Injection and Sotalol: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Foscarnet Injection
Sotalol
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest)
Interaction Deep Dive
Foscarnet can prolong the QT interval in some patients, which may result in ventricular tachycardia, ventricular fibrillation, and torsades de pointes. Because Class III antiarrhythmics may also prolong the QT interval and increase the risk of arrhythmias, the concurrent administration of foscarnet and a Class III antiarrhythmic is not recommended67.
Why it happens (mechanism)
Additive cardiac effects
Literature reports
4 reports — tap to read
a) Because ibutilide prolongs the QT interval, this agent should not be given concomitantly with other drugs that also prolong the QT interval 1.
b) A 72-year-old woman developed torsade de pointes while on oral acecainide therapy. The torsade de pointes resolved when acecainide was discontinued 2.
c) In 1 patient, torsade de pointes was reported on 2 occasions soon after initiation of oral amiodarone therapy at relatively low doses. The first event occurred 36 hours after the patient received a total loading dose of 1600 milligrams and amiodarone was discontinued. Twenty days later amiodarone was restarted at 200 milligrams/day and torsade de pointes occurred on the third day of treatment. Amiodarone was discontinued 3.
d) Azimilide produces dose-dependent prolongation of QT and QTc intervals in the absence of clinically significant effects on heart rate and PR and QRS intervals. These effects occurred whether azimilide was administered as a single IV dose, as a single oral dose, or in multiple oral dose regimens 45.
Common questions
Can I take Foscarnet Injection and Sotalol together?
An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Foscarnet Injection and Sotalol interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Foscarnet Injection or Sotalol need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (7)
- Product Information: Corvert(R), ibutilide fumarate injection. Pharmacia & Upjohn Co. Kalamazoo, Michigan, 2000. DailyMed
- Chow MJ, Piergies AA, Bowsher DJ, et al: Torsade de pointes induced by N-acetylprocainamide. J Am Coll Cardiol 1984; 4:621-624. PubMed
- Faggiano P, Gardini A, D'Aloia A, et al: Torsade de pointes occurring early during oral amiodarone treatment. Int J Cardiol 1996; 55(2):205-208. DOI
- Corey AE, Agnew JR, Valentine SN, et al: Azimilide pharmacokinetics following intravenous and oral administration of a solution and capsule formulation. J Clin Pharmacol 1999; 39(12):1272-1276. PubMed
- Karam R, Marcello S, Brooks RR, et al: Azilimide dihydrochloride, a novel antiarrhythmic agent. Am J Cardiol 1998; 81(6A):40D-46D.
- Product Information: Betapace(R), sotalol HCl. Berlex Laboratories, Wayne, NJ, 2001. DailyMed
- Product Information: Foscavir(R), foscarnet. AstraZeneca, Inc. Alexandria, VA, 1998. DailyMed
Keep reading about Foscarnet Injection
Keep reading about Sotalol
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