Hello and thanks for your query
is used to treat rapid heart rate
conditions like Atrial fibrillation
. It act by lowering the heart rate. As you have taken double dose accidentally, it is possible as also you have noticed the slow heart rate. This can be a emergency if your heart rate falls less than 50 in day time and less than 40 in night while sleeping. You may need temporary Pacemaker depending on the condition and heart rate.
Now do not take your second dose of Diltizem and it is better to get admitted in hospital for observation and keep a check on heart rate. If you feel dizziness
, sweating or any other abnormal symptoms than immediately rush to ER.