Nortriptyline, increased heart rate and training

Morning folks.

After a neck injury and a bit of nerve damage in my neck I have been prescribed Nortriptyline. This is traditionally an anti- depressant but in lower doses is used for nerve pain too.

Since taking this drug I have noticed a big increase in resting heart rate and my heart rate whilst doing workouts. My resting heart rate before was 45bpm and if I was doing sweet spot workouts would top out at about 170bpm.

Current my resting heart rate is now around 65 bpm and whilst doing sweet spot workouts I’m topping out at 195bpm which normally be my top end doing anaerobic workouts.

It’s noticeably harder to finish sweet spot now probably due to extra strain on the CV system. I have also completed another ramp test to adjust my FTP. I have an appointment with my GP but will unlikely get any sports specific advice.

I haven’t tried any VO2 or anaerobic yet either as I’m sure this will push my heart rate in the 200s.

Have anybody had similar experiences or advice?