UTI antibiotics, such as fosfomycin, nitrofurantoin, sulfamethoxazole + trimethoprim, and ceftriaxone, help eliminate the bacteria causing the infection. They can relieve symptoms such as pain or discomfort when urinating and a frequent urge to urinate.
A urinary tract infection can develop in any part of the urinary tract, including the bladder, urethra, or kidneys. When the infection is caused by bacteria, treatment usually involves antibiotics.
If a UTI is suspected, it is important to see a gynecologist, urologist, or primary care provider. A doctor can confirm whether antibiotics are needed and recommend the most appropriate treatment.
UTI antibiotics
The most commonly prescribed UTI antibiotics are:
1. Fosfomycin
Fosfomycin is a single-dose UTI antibiotic that is usually used to treat cystitis, especially in women who are not pregnant and do not have a history of urinary tract abnormalities.
After treatment with fosfomycin, UTI symptoms are expected to improve within 2 to 3 days.
How to take: The contents of 1 fosfomycin packet should be dissolved in about 3 to 4 ounces of water and mixed with a spoon. This mixture should preferably be taken at night on an empty stomach, before going to bed and after urinating.
2. Nitrofurantoin
Nitrofurantoin is one of the most commonly prescribed antibiotics for acute urinary tract infections, such as cystitis. It may also be used to treat asymptomatic bacteriuria during pregnancy and, in some cases, to help prevent UTIs.
How to take: Nitrofurantoin should be taken exactly as prescribed by a doctor. For the monohydrate/macrocrystals formulation, 100 mg is commonly taken with food every 12 hours for 5 days. Other nitrofurantoin formulations may be taken every 6 hours for 7 days, depending on the doctor’s instructions.
3. Sulfamethoxazole + trimethoprim
The combination of sulfamethoxazole + trimethoprim is an antibiotic that is usually prescribed for UTIs caused by susceptible microorganisms. It is one of the main treatment options for cystitis.
In the US, sulfamethoxazole + trimethoprim is commonly available as a generic medication and under brand names such as Bactrim and Septra.
How to take: For adults and children over 12 years old, the usual dose is 2 tablets of sulfamethoxazole + trimethoprim 400 mg + 80 mg, or 1 double-strength tablet of 800 mg + 160 mg, every 12 hours. Treatment duration varies according to the doctor’s instructions.
4. Amoxicillin + clavulanate
Amoxicillin + clavulanate is an alternative for treating UTIs, especially in cases of cystitis or when other UTI antibiotics cannot be used.
This antibiotic is available as tablets and oral suspensions in different strengths. In the US, it is commonly available as a generic medication and under the brand name Augmentin.
How to take: Amoxicillin + clavulanate 500 mg + 125 mg tablets are usually taken as 1 tablet every 8 hours. Treatment typically lasts 3 to 7 days, depending on the doctor’s instructions.
5. Ciprofloxacin
Ciprofloxacin is an antibiotic that is usually prescribed for more serious cases of UTI, such as pyelonephritis. It may also be used for people with a urinary catheter or urinary tract malformations, for example.
How to take: The dose of ciprofloxacin for a UTI varies depending on the severity of the infection. In milder cases, 1 tablet of 250 mg every 12 hours for up to 7 days is usually prescribed.
6. Ceftriaxone
Ceftriaxone is a UTI antibiotic that is usually used in more serious cases, such as pyelonephritis. It can be given as an injection directly into a vein or muscle.
In some cases, ceftriaxone may also be used as a single-dose treatment for a UTI.
How to take: The usual ceftriaxone dose for adults and children over 12 years old ranges from 1 to 2 g given directly into a vein once daily.
Possible side effects
The most common side effects of UTI antibiotics are:
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Diarrhea;
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Nausea;
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Vomiting;
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Abdominal discomfort or pain;
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Headache;
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Dizziness;
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Skin redness;
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Itching on the body.
Although rare, serious allergic reactions can also occur during treatment with UTI antibiotics, such as anaphylactic shock and angioedema. These reactions may cause symptoms such as swelling in parts of the body or shortness of breath.
When to use antibiotics
UTI antibiotics are usually prescribed when cystitis or pyelonephritis caused by bacteria is suspected. It is important to see a gynecologist, urologist, or primary care provider so that the most appropriate antibiotic can be prescribed.
The doctor may also order urine tests, such as a urine culture with an antibiotic susceptibility test, to identify the microorganism causing the infection and the best antibiotics for treating the UTI.
Care during treatment
Some precautions are recommended during treatment with UTI antibiotics, such as:
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Taking the antibiotic correctly, according to the doctor’s instructions;
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Completing the full course of treatment, even if symptoms improve, and not stopping the antibiotic early;
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Seeing the doctor again if symptoms do not improve after 3 to 4 days of treatment;
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Asking the doctor or pharmacist any questions about how to use the antibiotic, such as when to take it and whether it can be taken with food or milk.
It is important to follow the doctor’s instructions to prevent the infection from coming back and to avoid bacterial resistance, which can make treatment more difficult and take longer.