My 18 Year Old Daughter Was Prescribed Clindamycin For A

My 18 year old daughter was prescribed clindamycin for a serious infection from a recent root canal. She has been taking them since Thursday afternoon, 300 mg 4x a day. Since she started them she has been having terrible lower leg and foot spasms/cramps to the point where she finds it hard to sleep and can only find comfort while she is standing. Lying or sitting seems to make them occur. She is deathly allergic to penicillin, not sure if that has anything to do with this particular antibiotic. Any advice would sure bring comfort to her and myself. Thank you
Patricia Jenkins