Which drug is not acetylated?

Activation of which of the following receptors would be expected to decrease anxiety________?

A patient has seasonal allergic rhinitis and is on terfenadine, He develps cardiac arrhythmias after a course of antibiotics. Which of the following antibiotic could have been given________?

All of the given drugs are positive inotropes EXCEPT________?

Drug which crosses placental barrier is________?

Indirect sympathomimetics can________?