What are they?
The most commonly used antibiotics for urinary tract infections (UTIs) belong to the class of fluoroquinolones (nalidixic acid, norfloxacin, ciprofloxacin, levofloxacin, ofloxacin).
Alternatively, other molecules belonging to various pharmacological classes (e.g. trimethoprim, nitrofurantoin, amoxicillin, ampicillin, cephalexin, cefuroxime, fosfomycin) are used, either as monotherapy or in combination (e.g. trimethoprim+sulfamethoxazole or amoxicillin+clavulanic acid).
All these medications must still be prescribed by your doctor.
Which one to choose
Different antibiotics and treatment regimens are used to treat UTIs, depending on:
- the localization of infection in the low (cystitis, urethritis) or upper urinary tract (pyelonephritis);
- the presence of urinary tract complications (malformations, inflammation, stones, etc.);
- the duration of infection (sporadic or recurrent form, acute or chronic infection);
- the identity of the germs involved from time to time (Escherichia coli, Staphylococcus saprophyticus, various species of Proteus and Klebsiella, Pseudomonas aeruginosa, Staphylococcus epidermidis, Enterococcus faecalis) and their sensitivity to individual molecules.
How to use them
The identity of the bacteria involved (etiological diagnosis) and their sensitivity to antibiotics are investigated by urine culture and antibiogram. The table summarizes the general indications.
| Therapy | In case of… |
|---|---|
| Empirically based antibiotic therapy using a broad-spectrum drug (i.e. active on a wide range of bacteria known to be the main culprits of UTIs) | Suspicion of an UTII in the presence of typical symptoms (urge to urinate frequently and urgently, burning when emitting urine, low abdominal pain or high lumbar) |
| Targeted antibiotic therapy, using urine culture for etiological diagnosis and antibiogram for the choice of the specific molecule for the identified germ |
Symptoms that persist or arise again after completion of therapy, thus suggesting that the bacteria responsible are not sensitive to thedrug used |
In pregnancy
In pregnancy it is particularly important to treat UTIs promptly even when they are asymptomatic (diagnosable by the presence of bacteria in the urine), taking into account, however, that some of the antibiotics mentioned are contraindicated.
Penicillins (such as amoxicillin, ampicillin), cephalosporins (such as cephalexin, cefuroxime) and fosfomycin can be taken without risk to the fetus.
The following should be avoided:
- sulfonamides (such as sulfamethoxazole), fluoroquinolones and tetracyclines throughout pregnancy;
- nitrofurantoin in the third trimester;
- trimethoprim in the first trimester.
Prophylaxis of recurrent UTIs
In recurrent forms (defined by the recurrence of at least three episodes of UTIs in 12 months or two in 6 months) antibacterial prophylaxis may be indicated.
For this purpose, prolonged therapy can be followed with one of the antibiotics mentioned or, alternatively, with cranberry extract (Vaccinium macrocarpum Aiton), whose effectiveness in reducing the frequency of relapses in patients with recurrent UTIs (in particular those, very widespread, from Escherichia coli) has now been verified by numerous clinical studies.
During treatment with cranberry extract, attention should be paid to its potential interference with some anticoagulant drugs (in particular warfarin) that may be taken during the same period.
Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.
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