Tonsillitis, a common condition often referred to as a sore throat, is an inflammation of the tonsils caused by either a bacterial or viral infection. Treatment depends on the cause and usually is delayed until lab test results are known. If viral, only symptom relief medications are given and the body will fight the infection on its own. If the tonsillitis is caused by bacteria, antibiotics are prescribed.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.


A throat swab culture, also known as culture and sensitivity, is done to identify the organisms that are causing the infection and to determine which antibiotics, if any, will work best to get rid of it. According to MedlinePlus, the vast majority of sore throats are viral infections. Group A streptococcus is the most common bacterial cause of a sore throat or tonsillitis. A rapid strep test screens for the group A streptococcus organism only and will not detect other causes of a sore throat.

Penicillin and Its Derivatives

According to the Mayo Clinic, penicillin, or one of its derivatives, taken by mouth for 10 days is the antibiotic treatment of choice for tonsillitis caused by group A streptococcus 1. A one-time injection of penicillin is occasionally used to treat bacterial tonsillitis. Other penicillin-like antibiotics include ampicillin, augmentin and azithromycin.


According to the National Information Program on Antibiotics, amoxicillin, a synthetic laboratory-made penicillin, doesn’t kill bacteria but stops their development by preventing them from creating walls that are vital for bacterial survival, as it keeps the content of the bacterial cell together 2.


Cephalosporin has similar chemical components as penicillin. Cephalexin, a type of cephalosporin, works by hindering the bacteria’s cell wall formation thus weakening the wall, causing it to rupture, which kills the bacteria.

Erythromycin and Tetracycline

Many people are allergic to penicillin and its derivatives. Erythromycin is a broad-spectrum antibiotic that is an active against a wide variety of bacteria. It has a range of antibacterial activity similar to penicillin so it is often used as an alternative for people who are allergic to penicillin. Tetracycline works by interfering with bacterial protein synthesis, thus preventing bacteria from manufacturing proteins vital for existence. It is an all-purpose antibiotic used for those allergic to penicillin to treat a wide range of bacterial infections.


Tonsillitis symptoms usually improve two or three days after treatment starts. The infection usually is cured after treatment is completed, but some people may need more than one course of antibiotics. The Mayo Clinic warns that failure to take all of the medication as directed may result in the infection worsening or spreading to other parts of the body 1.