Antibiotics for strep throat

Examples

Generic Name	Brand Name
amoxicillin	Amoxil
cephalexin	Keflex
erythromycin
penicillin

Penicillin is often the first choice of antibiotic for strep throat unless you are allergic to it.¹

Most antibiotics are taken for 10 days. Or, a single shot of penicillin may be given. The shot does not help you get better any faster than other types of penicillin.

How It Works

Antibiotics help kill the bacteria that cause infection. They also help the body's natural defences get rid of infection more quickly. Antibiotics may reduce your symptom of a sore throat but only by about 1½ days. Antibiotics are prescribed for strep throat mainly to reduce the risk of the infection spreading or the development of other complications.²

Why It Is Used

Antibiotics may be prescribed if you have strep throat. Your doctor may diagnose strep throat by talking to you, examining you, and looking in your mouth. The doctor also may lightly rub the back of your throat with a long cotton swab, to test for strep bacteria.

How Well It Works

Antibiotics may be prescribed if you have strep throat. Your doctor may diagnose strep throat by talking to you, examining you, and looking in your mouth. The doctor also may lightly rub the back of your throat with a long cotton swab, to test for strep bacteria.

Side Effects

Side effects of antibiotics may include:

• A skin rash.
• Diarrhea.
• Nausea.
• In rare cases, a life-threatening reaction (anaphylaxis) along with hives, shortness of breath, and shock.

Antibiotics also can change the normal bacteria in your body. This can lead to problems such as:

• A vaginal yeast infection.
• An infection of the intestines caused by Clostridium difficile bacteria (pseudomembranous enterocolitis).

A recent large study indicates that people who take erythromycin along with certain common medicines may have a greater risk of sudden cardiac death.³ The study showed that the risk of sudden cardiac death is greater when erythromycin is taken with some medicines that inhibit certain liver enzymes, than when these medicines are not taken together. Examples of medicines that inhibit liver enzymes are certain calcium channel blockers, certain antifungal medicines, and some antidepressants.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

It is possible for a person to carry strep bacteria in the throat but not have any symptoms. Antibiotic treatment is not usually needed if the strep infection is not actively causing symptoms. But it may be beneficial for the person carrying strep to be treated with antibiotics if he or she has a history of rheumatic fever, frequent strep throat infections, or family members with recurring strep infections.

It is important to take all of the antibiotic your doctor prescribes. Do not stop taking the antibiotics early just because you feel better. The infection may not go away if you do not take all of the antibiotics, as prescribed by your health professional. ⁴

Although it is important to take antibiotics for strep throat, they will not help if your sore throat is caused by a virus instead of strep bacteria. If you take antibiotics when you don't need them, they may not work when you do need them. Each time you take antibiotics, you are more likely to have some bacteria that the medicine does not kill. Over time, these bacteria can change (mutate) and become harder to kill. The antibiotics that used to kill them will no longer work. These bacteria are called antibiotic-resistant bacteria.

If you have trouble taking the medicines as prescribed due to side effects or other concerns, contact your doctor.

Children who have strep throat should stay home from day care or school until they have taken at least 1 full day of antibiotics and they are feeling well enough to return.

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Author:	Carrie Henley Sabra L. Katz-Wise	Last Updated: October 24, 2006
Medical Review:	Adam Husney, MD - Family Medicine Michael J. Sexton, MD - Pediatrics Donald R. Mintz, MD - Otolaryngology
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