Allergic reactions to antibiotics do not typically manifest as dizziness or fogginess, but rather rash, itching, angioedema (swelling of the mouth, and in severe cases the airway). Corticosteroids can lead to several
side effects including a sense
of fogginess (and
in others a sense of euphoria/insomnia), typically high rather than low blood pressure, and other side effects (even one dose of high doses of steroids can lead to acute confusion in older adults).