▁ad verse ▁effects ▁include ▁fe ver , ▁vom iting , ▁er yth ema , ▁der mat itis , ▁ang io ed ema , ▁pseud om emb ran ous ▁col itis . ▁ ▁P ain ▁and ▁infl amm ation ▁at ▁the ▁injection ▁site ▁is ▁also ▁common ▁for ▁parent er ally ▁admin ister ed ▁ β - la ct am ▁ant ib iot ics . ▁ ▁All er gy / h yp ers ens itivity ▁Im mun olog ically ▁medi ated ▁ad verse ▁re actions ▁to ▁any ▁ β - la ct am ▁ant ib i otic ▁may ▁occur ▁in ▁up ▁to ▁ 1 0 % ▁of ▁patients ▁receiving ▁that ▁agent ▁( a ▁small ▁fraction ▁of ▁which ▁are ▁truly ▁Ig E - medi ated ▁all erg ic ▁re actions , ▁see ▁am ox ic ill in ▁r ash ). ▁An ap hy la xis ▁will ▁occur ▁in ▁approximately ▁ 0 . 0 1 % ▁of ▁patients . ▁There ▁is ▁perhaps ▁a ▁ 5 – 1 0 % ▁cross - sens itivity ▁between ▁pen ic ill in - der iv atives , ▁ce phal os por ins , ▁and ▁car b ap en ems ; ▁but ▁this ▁figure ▁has ▁been ▁challeng ed ▁by ▁various ▁investig ators . ▁ ▁Nevertheless , ▁the ▁risk ▁of ▁cross - react ivity ▁is ▁sufficient ▁to ▁war rant ▁the ▁contra ind ic ation ▁of ▁all ▁ β - la ct am ▁ant ib iot ics ▁in ▁patients ▁with ▁a ▁history ▁of ▁severe ▁all erg ic ▁re actions ▁( urt ic aria ,