The most common immediate adverse reactions to transfusion are fever, chills and urticaria. The most potentially significant reactions include acute and delayed haemolytic transfusion reactions and bacterial contamination of blood products.
Penicillin allergy is an overreaction by your immune system to penicillin and other antibiotics in the beta-lactam family and closely related antibiotics. Doxycycline belongs to a class of drugs called Tetracyclines. Tetracyclines are unrelated to penicillins and therefore safe to take in hypersensitive patients. Other unrelated antibiotics include quinolones (e.g. ciprofloxacin), macrolides (e.g. clarithromycin), aminoglycosides (e.g. gentamicin) and glycopeptides (e.g. vancomycin).
Actually Doxycycline is apart of the tetracycline family, which is more commonly used to treat infections and inflammation of the skin (ie. acne) and doxycycline is also used to build your body`s resistance to Malaria.