Sorry if I missed this in your post. I think you need to see a doctor as soon as possible. An allergic (my assumption) reaction to an insect bite can be very dangerous...I believe.
I don't know what epinephrine is, but if it is a prescription medication, the best advice is to take it only for what it was prescribed for. Do not self prescribe to another condition because you have some left over on hand.
If a doctor gave you the prescription for your sting problem, then just be sure the doctor knows all of your conditions and medications.
I think only your doctor could answer your question. But I wouldn't fool around with what sounds like a fairly strong allergic reaction. Call the doctor and ask.
I'm very allergic to just about all antibiotics, and just started having heartbeat irregularities. So I'm concerned about epinephrine too. Guess I should ask my doctor also. Thanks for a good question.
Epinephrine is basically like adrenaline and for an adregenic afibber such as my self it is a definate no-no. I even have to ask for the Epi free form of novacaine at the dentist office.
I would definately see a Dr and tell him my contidions and see what they say.
De sure to tell him about your MVP.
You said you had "atrial misfire." Can you be more specific? Is that premature atrial contractions for example or some kind of atrial tachy? And how is your MVP graded - trace, mild, moderate, severe?
I have atrial arrhythmias and a moderate murmur. I also have asthma but use albuterol which is an adrenergic medication. It acts like adrenalin on the body. Yes, my heart rate increases when I use it but that's all.
You need to have the insect sting managed. Anytime you have red streaks spreading out from a bite or wound, it's considered a medical emergency. When you go in, tell them your heart problems and let them decide which treatment to use. From your description your heart could be having minor issues or more severe. It's hard to tell from your general description.