When an anxiety spell is coming on, there is no reason to siphon; there is no way to calm down until you just do calm down.
You're not the one inside of your partner's head so you can't dictate how much or how little medication he or she needs.
Sure, your partner won't always get the amount right, but it's not for you to judge, only to be supportive.
The only way there will be peace is if your partner has completed everything he or she needs to do.
It's essential that you know when your partner's freaking out and needs to be left alone and when he or she needs to be held and comforted.
These moods will vary and the only way to ensure you two are happy is knowing when you're needed and when you aren't.