Fast Heart Rate, Taking Inderal For Migraine And Chest Pain. Is This Elevated Heart Rate Dangerous?
Thank you for your query.
Inderal is propranolol, which is a beta-blocker. It acts on the pacemaker cells of the heart to reduce the rate. The dosage of the drug can be adjusted to achieve a slower heart rate.
Heart rate in the 90s is normal. Since you are taking the drug to prevent migraine and not for a cardiac cause, the dosage of the drug should be adjusted according to the episodes of migraine. The heart rate achieved is not relevant in this case. Of course, care should be taken that the heart rate does not drop to less than 60 per minute.
Since you have been on a beta-blocker for nearly 30 years, the beta receptors on the cardiac cells would have increased in number and sensitivity to the adrenergic hormones. Hence, if you do not take the drug, there will be an overshoot of beta-adrenergic effects including an increase in heart rate (due to unopposed effect of the hormones on supersensitive and increased number of receptors). That is the reason for the increase in heart rate.
Even though the LA preparation of Inderal is supposed to be a long acting drug, many a time it does not have a full 24 hour effect leading to fluctuations in heart rate towards the end of the dosing intervals.
The solutions for these could be:
1) You need a twice or thrice daily dose of Inderal which you should take care never to omit.
2) You can ask your treating doctor to switch over to a long acting, beta-1 specific beta blocker like metoprolol succinate or bisoprolol.
3) amitryptiline can sometimes cause an increase in the heart rate. Since you have switched over to another medicine, it is not relevant now.
I hope this answers your query. Feel free to contact me for any further clarifications.
With regards,
Dr RS Varma