Sulfa Drugs

     Sulfa drugs were the first antibacterial agent brought to market in the mid 1930’s.   It was around for the second world war and helped save many lives, but not as many as penicillin.  It was able to treat a wide range of bacterial infections when taken orally.  The trade name was Prontosil. 

     Sulfamethoxazole – sometimes combined with trimethoprim in a product called Bactrim – is a common drug used in the management of common problems in the outpatient setting. 

     Many other drugs are sulfa-based.  Some have antibacterial properties and some do not. 

What do they treat?

Sulfa drugs treat many infections including:

• Urinary tract infections
• Some respiratory tract infections (either alone or in combination with another antibiotic)
• Ear infections in kids
• Skin infections caused by MRSA
• Acne
• Some illnesses that result in diarrhea such as travelers’ diarrhea
• Some infections common in patients with HIV/AIDS

Common side effects

     Sulfa drugs are commonly associated with side effects as well as allergic reactions.  Those with HIV have a higher prevalence of adverse reactions.  Common side effects include:

• Rash (some can be serious)
• Stomach upset

Uncommon side effects

• Stevens-Johnson Syndrome (severe skin reaction)
• Hives
• Urinary tract disorders
• Blood disorders
• Toxic epidermal necrolysis (severe skin reaction)

     Those who are on this drug for long periods of time should have their blood counts monitored to watch for any blood disorders. 

The individual drugs

     Sulfamethoxazole-Trimethoprim  (Bactrim, Septra) is used in the treatment of bladder infections.  It is dosed twice a day and can be given for three days in uncomplicated infections.  It increases the risk of yeast infections. 

     The most common bacteria that causes bladder infection is E. coli.  Some communities are seeing a large increase in E. Coli resistance and therefore this drug is sometimes not used in the management of bladder infections. 

      Risk factors for resistance to Bactrim include: those who are currently on an antibiotic when diagnosed with a bladder infection, on Bactrim with in the last three months, those who have traveled to Mexico, and recent hospitalization. 

     Because of this resistance to sulfa drugs, quinolones are becoming a more popular choice for the treatment of urinary tract infections. 

Practical use

• This drug is falling out of favor
• It is often used in urinary tract infections, but with the increasing of bacterial resistance it is being used less often
• It is used for some respiratory tract infections, but is not often used because of increasing bacterial resistance