Burmese Python RI

Hey Guys, have a sick Burm here and had a few specific questions. The culture showed sensitivity to Fortaz (Ceftadzidime). What I'd like to know is what concentration people are using.

I see 1 gram, 2 gram, and 6 gram available. Being a Burm he is a big guy, 17.4 kilograms to be exact. Obviously 6 gram seems the best choice but I'm finding only 50 mL vials which means a bigger injection. My next question is what is the largest mL amount you can inject IM?

I'm waiting for a call from a compounding pharmacy but wanted some more input. My vet hasn't dealt with a snake this large so she's not familar with more than 2 gram Fortaz reconstitution. Also seems like right now Fortaz is hard to find, some pharmacies say they can't get it till April.
Any help is appreciated. I have been nebulizing with F10 SC and he has improved as far as no more discharge but is still wheezing. Tonight would be his last treatment (day 10).

Can you vet not do a phone consult with one more familiar with the medication involved?

If your vet needs a consult SEAVS.com in Fairfax, VA is one of the best exotic vets in the country, and they have prescribed Fortaz for RI's for my critters, so they'd be familiar with dosages.

She consulted with UGA vet school and even the Dr there was unsure. The packet insert on the drug just says add recommended volume of diluent.

Thanks bcr299 I will have her contact them tomorrow.

I'm sure you turned up the heat in his cage already.

I did turn up the heat and got a brand new humidifier. Finally found a Vet that had giant python experience and was able to get the Fortaz and told me the 3.5 ML dose is okay to do all at one location. Hopefully this does the trick.
He recommended shots every 72 hours for 8 doses, so 21 days on antibiotics.