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What is Co-Trimoxazole?

By Dulce Corazon
Updated May 17, 2024
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Co-trimoxazole is a popular sulfonamide antibiotic that is made up of two drugs, sulfamethoxazole and trimethoprim. It is frequently prescribed for the prevention and treatment of various bacterial infections such as otitis media or middle ear infection, traveler's diarrhea, chronic bronchitis, and urinary tract infections. Most co-trimoxazole are also effective in the treatment of a lung infection called pneumocystis jiroveci pneumonia, previously known as pneumocystis carinii pneumonia. This drug is not usually effective in treating infections caused by viruses.

For children with infections, co-trimoxazole is often given in liquid form. It also has a tablet form for older children and adults. In severe cases, the drug can also be administered through the veins of hospitalized patients. It is often advised to take co-trimoxazole as prescribed or directed by the physician.

Several instructions are also frequently given to patients taking co-trimoxazole. The medicine is best taken with a glass of water, usually an hour before eating or after two hours of eating. It can, however, be taken during mealtimes when it causes an upset stomach. Even when one is feeling better after a few doses of treatment, it is often necessary to finish the whole prescription.

Like most drugs, co-trimoxazole also has several side effects. Mild side effects include headache, fatigue, nausea, loss of appetite, and vomiting. One may also experience greater sensitivity to sunlight, thus most patients are instructed to use sunblock and to wear protective gear when out in the sun. Prolonged use can lead to growth of other organisms, like fungi. Severe side effect of the drug may take the form of bone marrow suppression. Individuals with suppressed bone marrow usually develop bruises, tiredness, bleeding, and frequent infections.

Individuals with allergies to the components of co-trimoxazole are often advised to avoid taking this drug. It is also necessary to tell the physician about the types of drugs one is allergic to during each consultation. Symptoms of an allergic reaction include skin rashes, breathing difficulty, chest pain, swallowing difficulty, and swelling of the face and lips. When this happens, one should stop taking the drug and seek immediate medical intervention.

Aside from those with allergies to co-trimoxazole, this drug is also not prescribed for women who are 36 weeks or more pregnant. Other individuals who should avoid this medication are babies younger than two months old and mothers who are breastfeeding. Older individuals suffering from liver and kidney disorders may need to have lesser doses of this medicine.

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Discussion Comments

By starrynight — On Nov 08, 2011

@indemnifyme - It's interesting that you're able to take this medicine, even though you have allergies. I actually read somewhere that co-trimoxazole has a pretty high incidence of allergic reaction.

Since it's a combination of two different kinds of antibiotics, the chance of side effects and allergic reactions are fairly high. And in fact, some countries restrict the usage of this kind of antibiotic! Some countries only allow doctors to prescribe co-trimoxazole when it will be the most effective drug for the medical condition.

By indemnifyme — On Nov 07, 2011

I'm allergic to penicillin, so when I get a urinary tract infection, I usually take co-trimoxazole. It works fine, but I have experienced some co-trimoxazole side effects, unfortunately.

The worst side effect I usually get is stomach issues. In fact, the first time I took this anti-biotic it actually made me throw up. I thought since it said on the bottle to take it on an empty stomach, it wouldn't work if I took it with food.

However, I decide to call the pharmacy and check, and they let me know I could take it with food and it would still work. I was so relieved!

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