Medicines for rhythm problems

There are lots of medicines out there for heart rhythm issues.

The first line that are beta blockers (eg bisoprolol) or calcium channel antagonists (eg diltiazem).  These generally slow the heart and can reduce extra beats, but aren’t very good at keeping you in a normal rhythm.

Anti-arrhythmic drugs can keep you in a normal rhythm. The most effective is a drug called amiodarone. This is a very powerful anti-arrhythmic, but it’s by no means perfect. It increases the time to recurrence of atrial fibrillation, reduces recurrent symptoms but doesn’t abolish them (ie it’s not 100% efficacious – probably more like 60%).  It does reduce ventricular tachycardia episodes.  It is overkill for supraventricular tachycardias and hangs around for ages so is generally avoided in this situation.

It also has lots of potentially nasty and lethal side effects. Most of these only occur after prolonged exposure after many years or decades but some can occur early. Initially the drug was used at doses of 400mg a day, but now we commonly use it at 200mg or even 100mg a day. The commonest side effects include problems with the thyroid gland but it can also cause grey discolouration of the skin, sensitivity to the sun, deposits on the surface of the eye causing issues with glare of vision particularly at night, taste problems, lung fibrosis, liver problems, damage to the peripheral nerves.

There are alternatives. The great hope for atrial fibrillation was dronedarone which was supposed to be as good as amiodarone but safer. It actually has the best evidence base of any antiarrhythmic ever but this is probably as it is the latest drug. Unfortunately it doesn’t seem to be as good as amiodarone and is dangerous in people with impaired heart function and has a warning against it that it can cause liver failure so it’s not so popular with doctors.

Flecainide or propafenone are pretty good in patients without heart disease and are pretty safe. In fact flecainide is my go to antiarrhythmic in pregnant patients. Sotalol is another option but isn’t particularly effective.

It can be quite complex choosing the right medication for yourself so it’s always helpful to see a specialist to discuss options and come up with a tailored personalised management plan.  Feel free to get in touch and make an appointment

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