Is heart block caused by medication reversible?

Yes,most of the time. Heart block caused by antibiotics or beta blocker or calcium channel blockers should improve after removal of the offending agent. It is imperative during the waiting time to watch for symptoms of syncope, dizziness and weakness and seek medical attention if any develop.
Yes. Generally when the medication is stopped the heart block should resolve. Some of the medications causing AV block include beta-blockers, calcium channel blockers, antiarrhythmics, and digoxin.