What is the most appropriate drug of choice for a 42-year-old patient with bacterial tonsillitis who is allergic to penicillins?

In the case of bacterial tonsillitis, particularly in patients with an allergy to penicillins, the use of erythromycin is favored as the most appropriate treatment. Erythromycin is a macrolide antibiotic that is effective against many bacteria that cause tonsillitis, including streptococci, which are often implicated.

Doxycycline, while effective for various bacterial infections, is not typically the first choice for tonsillitis due to its broader spectrum of activity and potential side effects. It is not generally used as a first-line agent for this particular condition.

Amoxicillin would usually be recommended for bacterial tonsillitis but is contraindicated in this case due to the patient's allergy to penicillins. Therefore, it would not be an appropriate choice.

Ciprofloxacin, a fluoroquinolone antibiotic, is generally not indicated for first-line treatment of tonsillitis and is reserved for more complicated or resistant cases.

Erythromycin is well-tolerated in patients allergic to penicillins and targets the common pathogens involved in tonsillitis effectively, making it the most suitable choice in this scenario.