Tetracycline is rarely used in pregnant and very young patients because it can:

Systemic sulfonamides are contraindicated during late pregnancy, lactation, and in ... ARF is rarely associated with newer sulfonamides, which are more soluble ... is the drug of choice because it can be given to patients with renal impairment, ...

Hello!

Tetracycline shouldn't be used in younger patients because of its effects on their teeth and bones.

In teeth, the drugs interfere with enamel development may cause a permanant yellow or gray or brown discolouration. In bone, the drugs form a stable compound in bone-forming tissue and may interfere with bone growth.

It may also harm a fetus under two months of pregnancy because of systemic sulfonamides.

I really hope this helped you out! :)