i have done a search to no avail.
i was wondering if speed interfers with your immune system, like mdma does?
Also how does penicillin react with drugs such as speed and mdma??
Yes, speed/meth weakens the immune system in much the same way that MDMA does.
Do a search in the Health forum -- there is a FAQ about antibiotics and MDMA -- and what applies to MDMA will also usually apply to other amphetamines.