I Am Taking Avodart For Years. I Received A Letter

I am taking Avodart for years. I received a letter from my insurance co. inform me that the co. dropping Avodart. They informed me there will be an alternative drug Terazonsin. I wonder if this drug will be comparable to Avodart. So far I did not notices any side effect from taking Avodart. I do not know about Terazosin, is this drug has side effect. Do i need to be concerned about it!