I have a Mirena fitted in 1995 - one of the first to be fitted with one. It was only licenced for three years when I first had it put in. After initial three months of spotting it was fine and dandy.
Then about a six months in, I had a metallic taste that lasted for three weeks out of every four. It got to the three year anniversary of the mirena, and I thought = great take it out - but was told it could stay in another 2 years.
The metallic taste remained. I saw every kind of specialist - dieticians etc - no one could tell me why.
In the end I couldn't bare the thrupenny bit taste and asked my doctor to take it out. She did and hey presto, the taste went down to about one week in every four! However, a definite improvement.
No one ever blamed the Mirena for making it so bad except me. I suspected it was a hormone connection, as this taste is often linked with pregnancy.
However, it did do it's job - because once it had been taken out in May 1999, I fell pregnant in November of that year - just as my DH's appointment had come through for the snip!
ALSO please do not be hounded into the Mirena as THE answer to flooding. At a later date a Consultant Gynae was desperate to stick one in to stop my flooding. I said NO about a hundred times. Been there done that - snip done! Even as I lay on my hospital bed to have a polyp removed, about to go under he asked me again. I wanted to hit him. He said it would stop my flooding. He said the polyp removal had nothing to do with my flooding.
HOW WRONG HE WAS! I had great joy telling his secretary I was fine once the polyp had gone!