A warm welcome to the forum.
I’m sorry to hear that your husband has not reacted well to the reduced serotonin related drugs. We have a lot of information on the Parkinson’s website about medications/ treatments that I think will be very useful to you - you can find it here.
In addition to this, we have a helpline service where you can speak to a Parkinson’s specialist about the concerns you have with your husband’s medication and they’ll be able to advise you accordingly.
Please contact them on 0808 800 0303 and do keep us posted on this.