s.o.s., si op. sit means si opus sit - if there is a need in Prescription
Similar to s.o.s., si op. sit
a.u. - auris utraque - both ears aa - ana - of each ad - ad - up to ad lib. - ad libitum - use as much as one desires; freely admov. - admove - apply agit - agita - stir/shake alt. h. - alternis horis - every other hour