A Dirty Hit? (I Need Filter Advice)

[Solinari]

Has anyone heard of a "dirty hit" before? It's when you inject heroin but feel terrible after it (usually about an hour or so afterwards), symptoms include usually feeling sick (not the nausea you get from opiates), shivering and/or shaking uncontrollably, generally feeling unwell and can sometimes include a terrible headache.

My friend has had a dirty hit a few times, the first one he had was the worst because of the headache, it was the worst headache he'd ever had. Thankfully that was the only time he had a headache, well he did get a headache another time but it was mild in comparison. He has been told the only thing that helps it is another hit, but he hasn't ever tried that and has been advised against it because it could make things worse, so he just rode it out.

I am wondering if anyone else has had a dirty hit before, what symptoms did one get and did one do anything to try and get rid of it (like having another hit)? My friend doesn't use heroin as much now, but when he does he usually injects it. Sometimes after an hour or so he starts to feel sick (the first sign of a dirty hit) then he gets paranoid that he will be in for a dirty hit, thankfully it hasn't happened recently but he is still worried about it.

What do we think about dirty hits, the causes, prevention and even treatment (of sorts) to get rid of it?