It could be possible that a shot of ampicillin clear up strep throat?

Streph throat: This is what my family does for strepth throat. But providers sometimes don't want to use this option due to concerns about allergic reactions.

Unlikely : A single injection of long acting intramuscular benzathine penicillin g has been shown to be effective in clearing strep.It provides a continuous blood level of the antibiotic that lasts 10 days or more. Injected Ampicillin has a half life in the blood of less than 4 hours, and is out of the system in less than 24 hrs.Injections every 6 hours over a 10 day period would meet todays recommendations.

No: A shot of Ampicillin will be excreted in 6 hours. You need to take penicillins for 10 days to eradicate group a streptococcus and prevent rheumatic fever.