Penicillin and amoxicillin are the first-line medications for strep throat. Both are taken by mouth for 10 days and are highly effective at killing the group A streptococcus bacteria responsible for the infection. Most people start feeling better within two to three days of their first dose, and they’re typically no longer contagious within 12 hours of starting treatment.
First-Line Antibiotics
Penicillin V and amoxicillin have been the standard treatment for strep throat for decades, and the bacteria that cause strep have not developed resistance to either one. The CDC lists both as first-choice options for children, teens, and adults.
Amoxicillin is often preferred for children because it tastes better in liquid form and can be taken just once or twice a day. Adults are typically prescribed penicillin V twice a day. Both require a full 10-day course, even though symptoms usually improve well before that. Stopping early increases the risk of the infection returning and raises the chance of complications like rheumatic fever, which can damage the heart.
Options for Penicillin Allergies
If you’re allergic to penicillin, your doctor has several alternatives. The choice depends on the type of allergic reaction you’ve had in the past.
- First-generation cephalosporins (cephalexin, cefadroxil): These are closely related to penicillin but are considered safe for people whose allergy causes a rash rather than a severe reaction like throat swelling or anaphylaxis. Both are taken for 10 days.
- Macrolides (clarithromycin, erythromycin): These belong to a completely different drug class and are appropriate for people with severe penicillin allergies. Clarithromycin is taken twice daily for 10 days.
- Clindamycin: Another alternative unrelated to penicillin, taken three times daily for 10 days. It’s sometimes chosen when other options aren’t tolerated.
All of these alternatives require the same 10-day course length as penicillin. There is no shorter antibiotic regimen currently recommended for strep throat.
Pain Relief While Antibiotics Work
Antibiotics kill the bacteria, but they don’t provide immediate pain relief. For the first couple of days, over-the-counter pain relievers do the heavy lifting. Ibuprofen (Advil, Motrin) and acetaminophen (Tylenol) both reduce throat pain and fever effectively. Ibuprofen has the added benefit of reducing inflammation in the throat.
A few simple remedies also help. Gargling with warm salt water, about a quarter teaspoon of salt in eight ounces of warm water, can ease soreness when repeated several times a day. Honey soothes irritated throat tissue (though it should never be given to children under 12 months). Cool liquids, popsicles, and soft foods can make eating more comfortable while your throat heals.
For severe throat pain, some doctors prescribe a single dose of a corticosteroid like dexamethasone alongside antibiotics. A BMJ clinical guideline found that corticosteroids increase the chance of complete pain resolution within 24 to 48 hours and shorten the time until pain relief begins. This is a one-time dose, not an ongoing medication, and it applies to both viral and bacterial sore throats in adults and children over age 5.
Why the Full 10 Days Matter
Most people feel dramatically better within two or three days of starting antibiotics. That improvement tempts many to stop taking the medication early. This is one of the most common mistakes with strep treatment.
The 10-day course exists specifically to prevent rheumatic fever, a serious inflammatory condition that can damage heart valves, joints, and the nervous system. Rheumatic fever is rare in the U.S. today precisely because antibiotics are used consistently. Stopping a course short also increases the chance of the infection lingering or bouncing back, potentially requiring a second round of treatment.
What Happens Without Treatment
Strep throat can resolve on its own in many cases, but leaving it untreated carries real risks. The bacteria can spread from the throat to the tonsils, sinuses, skin, middle ear, or even the bloodstream. Beyond direct spread, untreated strep can trigger inflammatory reactions throughout the body.
The most concerning complications include rheumatic fever, kidney inflammation (poststreptococcal glomerulonephritis), and scarlet fever, which produces a distinctive red rash. A less common condition called poststreptococcal reactive arthritis causes joint inflammation weeks after the initial infection. In children, there’s also an observed but still debated link between strep infections and worsening symptoms of OCD or tic disorders, known as PANDAS.
These complications are the reason strep throat is one of the few common sore throats that genuinely requires antibiotics. Most sore throats are viral and don’t benefit from antibiotics at all, but a confirmed strep diagnosis changes the calculation significantly.
When You Stop Being Contagious
You’re considered no longer contagious within 12 hours of taking your first antibiotic dose. Schools and daycares typically require children to have been on antibiotics for at least 12 hours before returning. Without antibiotics, strep throat remains contagious for two to three weeks, even after symptoms start to fade. This is one of the practical reasons treatment matters: it dramatically shortens the window during which you can pass the infection to others.