Any GPs around please - have a penicillin allergy question

[Feenie]

Will try to be brief.

My 5 year old ds has to have a tooth out under general anaesthetic in 2 weeks. He has some pain and we visited the dentist, who prescribed Amoxycillin.

I am allergic to penicillin, as are my sister and my two nieces. For this reason, any GPs have avoided giving penicillin to ds thus far. I am aware that penicillin allergies tend not to run in families, but GPs have decided (not me) that this does not seem to be the case in our family, and that it would be prudent to avoid it until he is older, at least.

This is on ds's dental notes, but dh took him, and failed to spot that this prescription was a derivative of the penicillin family.

I noticed straight away (I had anaphylactic shock as a baby when prescribed penicillin) and phoned the dentist. She insisted that amoxycillin is not penicillin, that she was 'well aware' of ds's notes, but that because it is not penicillin it was safe.

I disagreed, and took him to the GP, who said it is in the penicillin family, he should not be prescribed it and prescribed Erythamycin on the spot.

The dentist's receptionist says they will phone on Monday, and I will tell her what happened. My question is, what could the potential effects have been, at worst, if I had taken her advice and given ds the amoxycillin, and he turned out to be as allergic as I am?

Would like to spell it out to her so that she does not prescribe this to anyone else who could be allergic - if she prescribed it for me, for example, in her insistence that it is not penicillin, I assume the consequences could be very serious indeed?

Thank you for reading - this turned out to be very long!

[downpipe]

Dentist is wrong:Amoxicillin IS a type of penicillin.

Her confusion may lie in the fact that it is not Penicillin V,which is a specific type of penicillin that dentists may often prescribe.

But they are both in the penicillin family and in the case of allergy to one known type, all should be avoided.

She needs to read the BNF properly (British National Formulary, doctors drugs bible).

If someone is allergic to any type of penicillin, all should be avoided to minimise risk of allergic reaction.
If it was on the notes that your DS should not have penicillin, amoxicillin should not have been prescribed.Don't know what systems dentists use but on a GP's computer this would have been flagged up as a hazard before a prescription was issued even if the GP had not noticed it.If dentists hand write their prescriptions, the computer safety net is absent so their pharmacology knowledge has to be good but they can & should always refer to the BNF if in doubt.
IF your DS was truly allergic, worse case scenario could have been that amoxicillin may have caused severe anaphylaxis requiring emergency hospital treatment ,steroids, adrenalin, possibly ventilation if very severe.Anaphylaxis can be very rapid and very serious.
If anything had happened, her defence of thinking amoxicillin is not a penicillin would be inexcusable, it is a very basic pharmacological fact.
Hope this helps (I am a GP BTW).Glad your GP knows what he is doing!

[Feenie]

Thank you very much for your answer, downpipe - that's what I suspected, but didn't ask our GP outright what the potential consequences could have been.

Will relay this to the receptionist on Monday, and we will leave her practice. But would like her to know so that harm to anyone else can be avoided.

Thanks again