Cat skin is much tougher to puncture than human skin, especially boy cats. I made the mistake of using the same needle to pierce the penicillin bottle*, then the male cat's skin, which didn't go well at all. I depressed the plunger of the syringe after I "thought" I had the needle in his shoulder skin, but since I hadn't pierced his skin properly, the penicillin leaked onto his fur, which got onto DH who was holding the cat for me.
Now for a bit of backstory:
DH had some kind of infection as a child, was prescribed penicillin (not sure if pills or liquid suspension). His mother took him across the street to the pharmacy, and had him take his first dose while there. Within minutes - while still in the pharmacy - he started gasping for air and passed out. Luckily, the pharmacist had the wherewithal to arrange immediate medical attention from the medical area across the street. Ever since then, whenever asked about medicine allergies from a medical professional, he's responded that he's VERY allergic to penicillin. Of course the medical professional asks what type of reaction occurs with exposure to penicillin, which he answers: anaphylactic shock with respiratory arrest (yes, the medical professional's eyes grow wide when hearing this!)
Tonight, on day 3 of penicillin shots, DH told me that his hand that got the penicillin on it broke out in a reddened rash! OMG! Then he wondered why I went all drill sergeant on him while he was moving all around me trying to recapture the cat while I was holding an uncovered syringe with penicillin in it (I do NOT like for there to be a lot of movement nearby when I'm holding an uncovered syringe! I've heard too many needle stick injury stories I guess LOL)
The cats are sounding much better, and the girl cat's appetite has fully returned finally - they're both still getting the Lysine mixed in with their food to prevent relapse of the virus. DH's hand had already cleared up before he told me about him reacting to the dribbled penicillin. Tomorrow will be the last shot, and DH will be wearing gloves when he holds the cats! And, there'll be a lot less movement allowed in the vicinity of the uncovered needle too!
*Using the same needle to puncture both the medicine bottle dulls the needle somewhat. This doesn't matter too much if the skin receiving the injection is soft skin. But adult cat skin is challenging to me, much more so than humans, and even dogs. So after learning how tough a male cat's skin is, from now on I'll change to a fresh needle after withdrawing the meds from the bottle. To save on how many needles are used, tonight I tried filling today's injections and hopefully tomorrow's as well, but DH interrupted me with something, and I forgot which needle was the med bottle puncture needle. Next time I draw up many syringes at a time, I'll put a dot on the bottle-puncture needle with a sharpie.