Hi Doctor...I am a college educated 57 year young gentleman who has not used heroin since the late 1990 s, but fell to temptation yesterday involving extremely small amounts of high grade brown heroin in California (NOT Black Tar, but far superior brown powder. The problem is almost undoubtedly any toxic additives that the sellers must have also used, added by uneducated manufacturers or mixers, etc., hence causing the present small scale crisis that I MUST keep from developing into anything worse...but be that as it may....the product in question very quickly cooked up into an excellently appearing, exquisitely smelling clear brown liquid, with the rich and proper high grade attributes one would look for. Continuing, in addition to failing hitting any good veins (which are virtually nonexistent on these arms...the only sites I ever used...) cleanly on 3-4 attempts below the elbow at various different locations...and although as I say it looked, smelled, and cooked up into what appeared to be of unusual quality for that most often dubious product...yet today I am suffering rather severe tenderness at and around the injection sites, and as this is still very early in the overall treatment regimen or process (within 18 hours), I seek to nip this in the bud properly with the right meds, and certainly before any more serious interventions become necessary. Keep in mind my total consumption involved no more than barely a 1/4 gram....an extremely small amount to give rise to such sensitivity, pain, redness etc., around the attempted sites. Now I know very well that simply throwing ANY antibiotic at this, given its early stage, is an idiot s game, and would appreciate specific recommendations as to which antibiotic meds are more likely to be appropriate under the circumstances described? I have on hand Doxycycline 50 mgs., given for an eye infection recently, and also a full Z-Pack or Azithromycin 250mg, as yet untouched, for a previous totally non-drug related problem that cleared up before I needed to begin the Z-Pack at all. That s background. Question (and by the way, God willing I should get out of this one smoothly and non-invasively): Since I have these two fresh meds on hand, am already on one....would either or both of them be properly indicated to stave off particularly all early stage infections of the forearm tissues involved, some surrounding veins, etc.? Or do I need to use other more focused specific meds. I particularly thought of adding the Z-Pack because of its wide spectrum of action on a greater number of nasty organisms that could come from strong heroin cut by idiots who essentially ruined their own product....and endangered my health, life and limb etc? A speedy response would be most urgently and particularly appreciated. It is now approx 9:30pm Pacific time, 5-12-2014. Very much hope to hear from you soon. Many thanks.