I guess it would be your call....I'm not sure if there would be any negative effect if you started one med. and then switched to another. Tylan is used for reptiles with a R.I., so if you have to decide if you trust your friend enough to give you the proper dosage, and then decide if you think it's O.K. to switch. Esther mentioned sending a p.m. to Drache613, so with your question about the 2 drugs it would be good to ask her....or just go with the Tylan if this guy is experienced with it's use. Try not to worry too much, if she's been healthy all her life she should get through this just fine. Be sure to keep her temps. around 80 at night , and get a probiotic like Benebac, Acidophiliz+ or soy yogurt to build up her good gut flora.