After taking medicine, how long is a tonsil infection (possible strep)infectious for?

My friend woke up today feeling physically miserable, she went to the Dr. and they said she has a tonsil infection and it’s possibly strep (No lab results yet). She took her anti-biotics at 1PM and it’s now about 6PM. The anti-biotics they gave her she said “started with a ‘z’” (I’m not sure) She was to take 2 right away then one per day for the next five days.

She is afraid to be alone when she gets sick but I certainly don’t want to get sick either. I want to be with her but I have the fear that I will get it as well. How long is she contagious for? I seem to remember there being a certain amount of time you are still infectious for after taking the antibiotics. When would be the first safe time to see her?


Zithromycin? Comes in a foldable cardboard and foil blister pack thingie? That’s some hardcore stuff.

No clue about your actual question, though - I’ll be curious to see the answers, because I’ve had strep a bunch of times over the years and have never gotten a straight answer on that myself.

Every time I’ve been on any antibiotic the doctor has said that I’ll be infectious for 24 hours after the first dose.

Zithromax. Good stuff.

Same thing I’ve always heard, and also the rule of thumb they use at my kids’ old day care center.

BTW, just because your friend has strep doesn’t mean you’ll catch it if you sit in the same room and keep her company. After all, if that were the case, doctors and nurses would have strep constantly. My kids have had strep lots of times and I only got it once. It’s spread primarily though saliva so don’t get sneezed or coughed on, minimize touching, wash hands frequently. The fact you know she has strep is the best protection; it is usually spread before the sick person knows he’s sick.

From UpToDate (a superb source for practising docs):

The comment that data exists only for penicillin is not just filler. Penicillin works by killing the bug, whereas other antibiotics may only inhibit its replication thereby making it easier for the body’s natural immune system to deal with it (i.e. smaller numbers).

*GAS = group A streptococcus = the agent causing strept throat