Antibiotics for Strep Throat (Streptococcal Pharyngitis)
- Best antibiotics for Strep throat
- How to distinguish Strep from Sore throat
- Do you need antibiotic to treat strep throat?
- Antibiotics not working for strep throat
Last updated: August 08, 2017
Based on 2012 IDSA Updated Guideline for Managing Group A Streptococcal Pharyngitis 9.
Best Antibiotics for Strep Throat
- Penicillin - #1 treatment choice according to IDSA Updated Guideline9
- Amoxicillin - very effective, safe, and inexpensive
- Cephalexin - great for penicillin-allergic people, low cost 9
- Clindamycin - only for patients with immediate type hypersensitivity to penicillins 9
The best antibiotic treatment ensures balance between effectiveness, safety, cost, and convenience.
How to Distinguish Strep from Sore Throat?
Strep throat, also called streptococcal pharyngitis, is an infection with group A beta-hemolytic streptococcus bacteria. It is characterized by inflammation of the pharynx and tonsils. The illness is most common in children aged 5-12 years.
While the terms sore throat, tonsillitis, and "strep" are used interchangeably, there are essential differences between these conditions.
The most common symptoms of strep throat are:
- sore throat
- high temperature, usually over 38°C (101°F)
- swollen lymph glands in the neck
- white or yellow spots on the tonsils or back of throat
- fever and chills
- stomach-ache (especially in children)
Strep throat checklist
|More likely to be strep throat||Less likely to be strep throat|
|Age 5-15 years||Age 45 years or older|
|High fever (> 38 °C)||Afebrile|
|Absence of a cough||Cough|
|Exudative pharyngitis or tonsillitis||Stuffy, runny nose; conjunctivitis|
|Anterior cervical adenitis (tender nodes)||Hoarseness|
|Sudden onset of sore throat||Diarrhea|
|Recent close exposure to group A strep||Discrete oral ulcerative lesions|
|Current streptococcal pharyngitis epidemic|
Do you need antibiotic for strep throat?
Current IDSA (Infectious Diseases Society of America) guidelines recommend to make a test named confirmatory throat culture before prescribing an antibiotic4. Generally, if the diagnosis of strep throat is confirmed, the doctor will likely prescribe you an antibiotic.
Antibiotic therapy can be started immediately (without testing) when:
- Patient is very ill
- Culture results will be delayed for more than 72 hours
- Patient follow-up will be difficult
Benefits of antibiotics in the treatment of strep throat:
- Kill the bacteria and shorten the time the patient is contagious. This makes infection less likely to be transmitted to close contacts. The patient usually is no longer contagious 24 to 48 hours after starting antibiotic.
- Prevent rare complications. Although uncommon, strep bacteria can spread to other parts of the body causing ear or sinus infections or an abscess near the tonsils (peritonsillar abscess). Antibiotics may also prevent the Infection may trigger immune system to attack itself, which results in serious complications like rheumatic fever or post-streptococcal glomerulonephritis. Antibiotics help prevent this attack.
- Accelerate the resolution of symptoms and hasten healing.
Antibiotic selection depends on patient allergies, bacteriologic and clinical efficacy, frequency of administration, duration of therapy, potential side effects, compliance and cost.
You may want to learn about side effects associated with antibiotics.
Further you will learn about antibiotics approved for strep throat treatment with dosage recommendations and get comprehensive knowledge for wise use of medications.
- Well-proven excellent efficacy and safety. According to the recent research8, Penicillin is still considered the best choice to treat streptococcal pharyngitis (for those non-allergic to penicillins) in both adults and children. For more than 60 years penicillin retains its ability to kill group A streptococci.
- Penicillin has a narrow-spectrum and so does not promote antimicrobial resistance.
Penicillin V dosage:9
- Children: 250 mg two or three times daily for 10 days.
- Adults: 500 mg twice daily or 250 mg 4 times daily for 10 days.
Benzathine penicillin G (intramuscular):
When a patient is unlikely to complete the entire course of oral antibiotic, a single intramuscular dose of penicillin G benzathine (Bicillin L-A) is an option.
- <27 kg: 600 000 U, 1 dose
- ≥27 kg: 1 200 000 U, 1 dose
Why penicillin may not work?
- Despite extremely high susceptibility of Group A Streptococcus to penicillin, the failure of therapy with penicillins may occur due to beta-lactamase production by oral bacteria12.
- Penicillin alone may be ineffective for eliminating chronic pharyngeal streptococcal carriage.
Amoxicillin has a broader spectrum than penicillin. However, amoxicillin has no microbiologic advantage over the less expensive penicillin.
- More convenient treatment regimen. Some studies show that amoxicillin given just once a day may work as well as penicillin V given more often.
- Amoxicillin suspensions taste better than penicillin V suspensions.
- Gastrointestinal side effects and skin rash are more common with amoxicillin.
- Children: 50 mg/kg (maximum 1,000 mg) once daily; or alternatively 25 mg/kg (maximum 500 mg) twice daily for 10 days9.
- Adults: 500 mg three times daily for 10 days.
Amoxicillin/Clavulanate Potassium (Augmentin®)
- Amoxicillin-clavulanate is resistant to degradation from beta-lactamase produced by pathogens that may colonize the tonsils and pharynx.
- Amoxicillin-clavulanate is an effective treatment for recurrent streptococcal pharyngitis and chronic pharyngeal carriage of group A streptococci9.
- Its major adverse effect is diarrhea.
Amoxicillin/Clavulanate Potassium dosage:
- Children: 40 mg amoxicillin per kg per day, in two or three divided doses for 10 days (maximum 2,000 mg amoxicillin per day)9.
- Adults: 500 to 875 mg two times daily for 10 days.
Azithromycin (Zithromax Z-Pak®)
Azithromycin, a macrolide antibiotic, is an effective treatment for group A streptococcal pharyngitis and is considered a second-line therapy.
- Reasonable choice for patients allergic to penicillins.
- May cure streptococcal infections that fail treatment with penicillins 2.
- Azithromycin achieves high tonsillar tissue concentrations.
- Very simple and short once-daily dosing, particularly suitable for persons unwilling to a 10-day antibiotic regimen.
- Relatively low risk of gastrointestinal side effects.
- Increasing bacterial resistance 13.
Azithromycin dosage (5-day course):
- Children: The recommended dosage is 12 mg/kg once daily for 5 days. Or, alternatively, 20 mg/kg once daily for 3 days. (maximum 500 mg per day)9.
- Adults: The recommended dosage is 500 mg as a single dose on the first day, followed by 250 mg once daily for 4 days 1.
- Good choice for patients allergic to penicillin.
- Very effective. One study suggests that 10 days of clarithromycin may be more effective in eradicating group A streptococci than 5 days of azithromycin 10.
- Increasing bacterial resistance 13.
- Children: 7.5 mg/kg/dose twice daily for 10 days (maximum 250 mg per dose)9.
- Adults: 250 mg every 12 hours for 10 days.
- Very low resistance. Clindamycin resistance among Group A Streptococcus isolates in the United States is approximately 1%.
- Clindamycin is a reasonable drug of choice for treating penicillin-allergic patients 4.
- Clindamycin is very effective for streptococcal pharyngotonsillitis resistant to penicillin 11, as well as for chronic pharyngeal carriage of group A beta-hemolytic streptococci 14.
- Commonly causes diarrhea.
- Children: 7 mg per kg per dose 3 times daily for 10 days (maximum 300 mg per dose)9.
- Adults: 300 mg 3 times daily for 10 days.
Cephalosporins are superior to penicillin for relapse and recurrent infections.
Clinical research shows that a 10-day course of a cephalosporin antibiotic is superior to penicillin in eradicating group A beta-hemolytic streptococci 5. Narrower-spectrum cephalosporins such as cefadroxil or cephalexin are preferable to the broader-spectrum cephalosporins such as cefaclor, cefuroxime, cefixime, and cefpodoxime.
- Very effective 5.
- Superior for relapse and recurrent infections.
- Cephalexin has a relatively narrow-spectrum and therefore is preferable to the broader-spectrum cephalosporins such as cefaclor, cefuroxime, cefixime, and cefpodoxime.
- Frequent dosing.
- Children: 20 mg per kg per dose two times for 10 days (maximum 500 mg per dose)9.
- Adults: 500 mg two times daily for 10 days.
- Convenient once daily dosing.
- Low incidence of gastrointestinal side effects.
- Suspension has a good taste.
- Children: 30 mg/kg once daily for 10 days (maximum 1 g) 9.
- Adults: 1 g daily as a single dose or in 2 divided doses for 10 days.
Cefuroxime axetil (Ceftin®)
- Very effective.
- Safe for children and pregnant women (pregnancy category B).
- Unnecessarily broad antibacterial spectrum. IDSA Practice Guidelines 9 don't recommend cefuroxime axetil because narrow-spectrum cephalosporins (cefadroxil or cephalexin) are preferred.
Cefuroxime axetil dosage:
- Adults and adolescents (13 years and older): 250 mg two times daily for 10 days.
- Currently, the recommended course of cefuroxime for strep throat is 10 days. However, clinical studies 6-7 demonstrate that short course (4-5 day) of cefuroxime axetil is also very effective in eradicating the infection and preventing post-streptococcal sequelae.
- Short course of cefuroxime axetil (20 mg/kg/day, max. 500 mg, in two divided doses for 5 days) is effective for treating children aged 1-17 years with streptococcal tonsillopharyngitis 6.
- Potent antistreptococcal activity.
- Safe for children and pregnant women (pregnancy category B).
- Cefdinir provides a slightly higher eradication rate of group A streptococcus bacteria than penicillin V 3.
- Unnecessarily very broad antibacterial spectrum. IDSA Practice Guidelines 9 don't recommend cefdinir because narrow-spectrum cephalosporins (cefadroxil or cephalexin) are preferred.
- The FDA has approved a 5-day course of Cefdinir for the treatment of streptococcal pharyngitis.
Antibiotics NOT working for strep throat
This list will help you to avoid medical errors. Antibiotics NOT recommended for streptococcal pharyngitis:
- Metronidazole - not active against Streptococcus pyogenes.
- Trimethoprim-Sulfamethoxazole (Co-trimoxazole, Bactrim) - does not reliably eradicate pharyngeal infection.
- Tetracyclines - the high prevalence of resistant Streptococcus pyogenes strains.
- Fluoroquinolones - are expensive and have an unnecessarily broad spectrum of activity.
Many people are wondering if there are any over-the-counter (OTC) antibiotics? Currently, OTC oral antibiotics are not approved in the U.S.
Causes & spread
Strep throat is caused by Group A beta-hemolytic streptococci (Streptococcus pyogenes). The bacteria are usually spread by direct person-to-person contact, most likely through droplets of saliva or nasal secretions. The infection can easily be caught in crowded environments, e.g. schools, child care centers. The peak incidence occurs during winter and early spring.
The infection has an incubation period of two to five days. Patients with Group A Streptococcal pharyngitis can spread the bacteria for 2-5 days prior to symptoms start appearing, during acute illness, and, if not treated, for a week after symptoms resolution.
Group C streptococcus (GCS) is a relatively common cause of acute pharyngitis in college students and adults.
Because many of the signs and symptoms of streptococcal pharyngitis are non-specific it is recommended that the clinical diagnosis is confirmed with laboratory tests. Throat cultures are the conventional gold standard method for confirming the diagnosis.
- 1. Hooton TM. A comparison of azithromycin and penicillin V for the treatment of streptococcal pharyngitis. Am J Med. 1991 Sep 12;91(3A):23S-26S. PubMed
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- 3. Tack KJ, Henry DC, Gooch WM, Brink DN, Keyserling CH. Free in PMC Five-day cefdinir treatment for streptococcal pharyngitis. Cefdinir Pharyngitis Study Group. Antimicrob Agents Chemother. 1998 May;42(5):1073-5. PubMed
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Published: January 20, 2009
Last updated: August 08, 2017