Treatment Guidelines for Urinary Tract Infections (UTIs) and the role of Amoxicillin

Urinary tract infections (UTIs), while uncomfortable, are a very common type of infection. While they can impact both men and women, women are most commonly affected — up to 70% of women will experience a UTI in their lifetime, and Canadian women make about 500,000 doctor visits per year for a UTI. 

Fortunately, UTIs are treatable, especially if you see a doctor as soon as you can. There are a few antibiotics primary care providers turn to when treating UTIs. There are a few factors they consider when deciding to prescribe one antibiotic over another.

Amoxicillin is one common type of antibiotic that can be used to treat a UTI. However, you might have questions about the medication itself and how it works. In this blog, we’ll cover some treatment approaches for UTIs and highlight when amoxicillin might be helpful and why. 

Types of UTIs 

There are several types of UTIs. The type of UTI diagnosed will impact which antibiotic a primary care provider prescribes and the duration of treatment.

UTIs are often classified as uncomplicated and complicated. Because treatment can be so varied, it’s important to see a primary care provider right away to determine your next course of action.

If you’re having trouble seeing a provider at a convenient time, Maple can help. Through secure text, audio, or video call, doctors or nurse practitioners on Maple can diagnose conditions and help you with your next steps 24/7/365. When you’re tossing and turning because you can’t sleep from a UTI or can’t take the time off work, Maple can connect you within a few minutes. 

Uncomplicated UTIs

An uncomplicated UTI, or bladder infection (cystitis) are among the most common types of UTIs.

The characteristics of an uncomplicated UTI include:   

• Involves the lower urinary tract, such as the bladder and urethra.
• Occurs in women, as their anatomy makes them more susceptible to bacterial exposure from the rectum.
• Occurs in healthy individuals that have normal urinary tract anatomy. 
• Occurs in individuals who do not have any other major health conditions. 
• Typically responds well to an outpatient antibiotic treatment.  

Treating Uncomplicated UTIs

There are several antibiotics that can be given to treat a UTI. A healthcare provider will select the best antibiotic for treatment based on:

• The bacteria identified in a urine culture, which is used to diagnose UTIs
• The type of UTI diagnosed (complicated or uncomplicated)
• Any other existing medical conditions one may have 
• Other medications one may be taking  

Further consideration will also be given Canadian guidelines that recommend first-, second-, and third-line choices of antibiotics for the different types of UTIs. These guidelines have been established based on how effective the antibiotic is at killing bacteria, what types it kills, bacteria resistance patterns, and safety. Many second- and third-line antibiotics can be as effective as the first-line ones but are listed as alternatives for reasons such as intolerance, ease of administration, and cost. A primary care provider such as a doctor or nurse practitioner will be able to diagnose you appropriately and prescribe the necessary medications. 

Currently, the first-line agents —  or the first choice of antibiotics — to treat an uncomplicated UTI are: 

• Trimethoprim/sulfamethoxazole: One double-strength tablet twice daily 
• Trimethoprim: 200mg once daily 
• Nitrofurantoin: 100mg twice daily for five days
• Fosfomycin: 3g dissolved in ½ cup of cold water as a single dose

If these antibiotics cannot be used due to allergies, medication interactions or other medical conditions, second-line antibiotics that can be used to treat an uncomplicated UTI include:

• Amoxicillin 500mg three times a day for seven days
• Ciprofloxacin 500mg once daily for three days

The third-line treatments include: 

• Cephalexin 500mg twice daily 
• Levofloxacin 250mg once daily 

Complicated UTIs
Several risk factors can complicate UTIs. Because they have a higher chance of treatment failure, they may require more interventions from your doctor. 

A complicated UTI:

• Infection extends beyond the bladder.
• Occurs in men.
• Occurs in people with structural abnormalities in their urinary tract system (such as a kidney stone).
• Occurs in individuals who have undergone recent urological surgery or kidney transplant.
• Occurs in people with diabetes.
• Occurs in pregnant or immunocompromised people.  
• Has an increased risk for poor outcomes like sepsis, treatment failure, or recurrent infections. 

UTI diagnoses are based on the bacteria identified in a urine culture, your medical history, and presenting symptoms.

Symptoms of an uncomplicated UTI may include:

• Painful urination
• Urinary frequency or urgency
• Difficulty urinating or fully emptying your bladder 
• Blood in your urine 
• Pain above your pelvic bone (Suprapubic pain) 

Symptoms of a complicated UTI include any of the above as well as possible: 

• Pain on either side of your back between the bottom of your ribs and just above your hip (Flank pain)
• Fever
• Chills or rigors (shivering) 
• Nausea/vomiting 

If you don’t have urinary symptoms, it’s likely not a UTI. Identifying symptoms is critical to establishing an accurate UTI diagnosis. If there are no symptoms, you could experience a phenomenon known as asymptomatic bacteriuria (ASB). ASB is when bacteria is identified in the urine without any urinary symptoms. However, it is harmless and does not require antibiotics.  

The only people who should be considered for treatment with ASB are those who are pregnant, are immunocompromised, or have undergone recent surgery on their urinary tract system. 

Treating Complicated UTIs

The first-line agents, or the first choice of antibiotics to treat a complicated UTI include: 

• Trimethoprim/sulfamethoxazole: One double-strength tablet twice daily for 10 to 14 days
• Trimethoprim: 200mg once daily 10-14 days
• Nitrofurantoin: 100mg four times daily for 10 to 14 days
• Ciprofloxacin: 500mg twice daily for 10-14 days
• Norfloxacin: 400mg twice daily for 10-14 days
• Levofloxacin: 500mg once daily for 10 days 

If these antibiotics cannot be used due to allergies, medication interactions, or other conditions, second-line therapy can be tried using:

• Amoxicillin/Clavulanate 875mg twice daily for 10 to 14 days

IV Antibiotics for a Complicated UTI

Some people with a complicated UTI may need treatment with IV antibiotics.

People may need IV antibiotics in some of these circumstances: 

• If you can’t tolerate taking pills.
• If your gastrointestinal tract cannot absorb medication effectively.
• The bacteria in your urine is resistant to oral antibiotics.
• If you’re considered medically unstable (blood pressure and heart rate changes) due to the severity of the infection. 

Overview of Amoxicillin 

Amoxicillin is a penicillin antibiotic that can treat a range of infections, including UTIs. It works by interfering with the bacterial cell wall stopping the growth of bacteria and killing the bacteria. Amoxicillin, like other antibiotics, is only effective against bacteria. It won’t treat viral or yeast infections. 

When primary care providers are diagnosing UTIs, urine cultures will identify the type of bacteria that is causing the UTI. Further lab testing on the bacteria will determine what antibiotics can best kill the bacteria.

Due to high rates of bacteria becoming resistant to amoxicillin, a urine culture must be done to ensure the bacteria will respond to the treatment. When a urine culture confirms that amoxicillin would work at eradicating that bacteria, it can be an effective treatment.

Pregnant people, children, and people who reside in long-term care homes will often be prescribed amoxicillin. For people with asymptomatic bacteriuria requiring treatment (such as in pregnancy, pre- or post-surgery on the genitourinary tract), amoxicillin may also be a fit.

Standard dosages for Amoxicillin for UTIs

The standard doses for amoxicillin for a UTI are: 

• Adults: 500mg of amoxicillin three times a day for seven days
• Children: 40mg/Kg/day given in 3 divided doses per day for seven to 14 days

In circumstances where adults have impaired kidney function, dosing is:

• 250mg three times per day for seven days

Amoxicillin and all antibiotics must be taken as directed. Misuse, over- or under-use of amoxicillin could cause bacteria to grow resistant to the drug.

If you miss a dose of your antibiotic, do not take a double dose. Take the missed dose when you remember, or if it is near your next scheduled dose, skip it and continue to follow your schedule until your entire treatment course is complete unless directed otherwise by your healthcare provider.

Possible side effects of Amoxicillin

Typically, amoxicillin is well tolerated; however, there are some side effects to watch out for when taking this antibiotic.

Reactions and side effects may include: 

• Allergic reactions range from mild with hives to severe with anaphylaxis.
• Skin rashes
• Nausea, vomiting or diarrhea
• Oral thrush or yeast infections
• Drug-induced liver injury (elevation of liver enzymes).
• Anemia or other changes in blood cell counts.
• Clostridium Difficile Colitis, an infectious diarrhea that causes severe inflammation in the gut that is sometimes fatal. 

You should not take amoxicillin if you have a known penicillin allergy, are allergic to anything in penicillin medication, or have a confirmed or suspected mononucleosis infection. 

Understanding the right treatment for urinary tract infections is important for your recovery journey. While UTIs can be quite common, prompt medical attention and the right antibiotics, such as amoxicillin, can lead to quick and effective treatment. Don’t delay care because you can’t take the time off — doctors and nurse practitioners on Maple can give you the advice you need to get you better, faster.  

By staying informed about the treatment options available, including when amoxicillin might be indicated, you can ensure a faster recovery and better manage your health. 

The information presented here is for educational purposes and is not meant to replace the advice from your medical professional. Virtual care is not meant for medical emergencies. If you are experiencing an emergency like chest pain or difficulties breathing, for example, please call 911 or go to your nearest emergency room.