As stated before, Metoprolol is often the first drug that's tried because its usually easily tolerated by most. The dose prescribed for you, 25mg is quite small. By comparison, I'm on 75mg per day, and have been as high as 200mg per day prior to my ablation for SVT. I take it now mainly for mild hypertension. Its very effective for me. I would suggest that you try and push through the tired feeling and you have should adjust to the drug. The plasma half life of Metoprolol Tartrate is around 4 hours for most people. This means that every 4 hours, the amount of drug in your blood is diminished by 50%. Some quick math will show you that within 24 hours, there is practically nothing remaining. This also means that there is minimal therapeutic effect as the day wears on. But your physician may start you on a low dose, and adjust you upwards when its shown you can tolerate it.
Safe to take.. Its the first line treatment for pvc's under a 10% or 15% burden..
Dangerous to just quit if youre taking it every day.. Never discontinue cardiac medicines without first consulting your doctor, as this can cause rebound effects that make your symptoms worse. These drugs typically require you to be weaned off them over time, or replaced with an alternate medication to mitigate symptoms. This applies pretty well to all cardiac medicine.. Its a good rule of thumb.
If the medicines not working you can just switch medicine or go for an ablation.. Just gotta keep your doctor in the loop.
It lowers your blood pressure which can make you feel tired.
The medicine youre taking works by partially blocking the sympathetic nervous system (the part of your body that deals with things like adrenaline).. This lowers ventricular irritability and should in theory lower your pvcs.
Sometimes its just not sufficient to fix the symptoms though, which is why we have alternatives available.