Bactrim - Uses - Dosages - Side Effects - Precautions

Bactrim: Frequently Asked Questions Answered

What Is Bactrim?

Bactrim is the trade name of an antibiotic combination of sulfamethoxazole and trimethoprim. It is used against various infection-causing bacteria, including opportunistic infections in immunosuppressed patients. Generally, the composition is 1:5 ratios of trimethoprim and sulfamethoxazole. Its dosages available are in oral and intravenous forms. Trimethoprim is a folate inhibitor that prevents the synthesis of bacterial DNA. Sulfamethoxazole is a sulfonamide with similar properties, and hence both are bacteriostatic in action.

What are the uses of Bactrim?

Bactrim is a potent medication used to cure resistant bacterial infections, as follows:

  • Effective against pneumocystis pneumonia among HIV/AIDS patients.
  • MRSA (methicillin-resistant Staphylococcus aureus) strains causing skin diseases.
  • Urinary tract infections.
  • Gastrointestinal tract infections.
  • Sepsis.
  • Respiratory tract infections.
  • Renal infections.
  • Toxoplasmosis in immunosuppressed patients.
  • Sensitive areas like inner ear infections.
  • Traveler’s diarrhea.
  • Cholera and typhoid.
  • Wound infections.
  • Bronchitis.
  • Shigellosis.
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What are the side effects of Bactrim?

Bactrim, a potent antibiotic amalgamation, has various adverse effects. Some are as follows:

  • Allergic reactions like hives, rashes, blisters, itching, and swelling, etc.
  • Fatal pregnancy; can cause several congenital disorders if taken during the first 3-months.
  • Chronic kidney diseases.
  • Hepatic failure.
  • Extreme sensitivity to sunlight can cause severe sunburn.
  • Jaundice.
  • Liver damage like porphyria.
  • Sometimes may cause persistent diarrhea due to Clostridium difficile infection.
  • Not advisable for patients with sulfate intolerance.
  • Blood diseases like aplastic anemia (bone marrow stops making RBC) and agranulocytosis (deficiency of WBC).
  • Yeast infection in long-term users.
S.no Product Name Dosage Form
1. Bactrim DS Sulphamethoxazole 800mg+trimethoprim 160mg Tablet
2. Bactrim Sulphamethoxazole 200mg+trimethoprim(cotrimoxazole) 40mg Suspension
3. Bactimax Miconazole 2 %w/w+mometasone 0.1 %w/w+nadifloxacin 1 % w/w Cream


Frequently Asked Questions about Bactrim

1. How to calculate Bactrim dose?

Bactrim dosages depend on the medical conditions and age of patients. For pediatric use, the dosage is calculated per body weight. For UTI treatment, the general dosage is 40 mg per kg for sulfamethoxazole, and 8 mg of trimethoprim in children after every 12 hrs daily continued for 5 days.

2. Is Bactrim stronger than Amoxicillin?

Yes. Amoxicillin is an antibiotic belonging to the drug class group penicillin used to treat bacterial infections. In contrast, Bactrim is a strong combination of antibiotics trimethoprim and sulfamethoxazole used to treat unresponsive infections. However, the side effects and precautions for amoxillinare far less than Bactrim as the latter is harmful to kidneys and lungs.

3. Is Septra and Bactrim the same thing?

Yes. Both are the same combination of antibiotics with uses to treat many acute infections like the inner ear, bronchitis, immunocompromised pneumonia, traveler’s diarrhea, etc. Both are a combination of strong antibiotics trimethoprim and sulfamethoxazole and have some anti-inflammatory properties like severe rhinosinusitis. Bactrim should be taken with precaution as it shows many adverse drug interactions.

4. Is Bactrim a sulfa drug?

Yes. Bactrim contains sulfamethoxazole which is a sulfonamide-containing antibiotic. It acts by preventing the synthesis of folic acid formation, thereby killing the bacterium. Hence, Bactrim should never be taken if a patient is allergic to sulfa drugs. One must also take precautions to have it with plenty of water to prevent damage to the kidneys.

5. Is Bactrim a strong antibiotic?

Yes. Bactrim is a potent drug combination used to treat opportunistic infections of pneumonia, skin, bronchitis, traveler’s diarrhea, respiratory and intestine infections. Both trimethoprim and sulfamethoxazole act to deprive folic acid bacteria, essential for the growth of such conditions. However, it should not be taken by pregnant and breastfeeding mothers or children younger than 2-months-old.

6. How quickly does Bactrim work?

Bactrim is a potent combination antibiotic that is absorbed quickly after ingestion and starts acting within 1 to 4 hours after administration. The bactericidal action will remain for 12 hours. Patients with urinary tract infections or UTI have reported a steady recovery within 3-days. Still, they are recommended to complete the dose to prevent the growth of antibiotic-resistant strains of bacteria within the body.

7. Can I eat yogurt with Bactrim?

Yes. There are no reports of adverse interactions between Bactrim and yogurt or other dairy products. On the contrary, some studies show that eating yogurt or probiotic-containing foods during antibiotic treatments is beneficial in preventing antibiotic-related diarrhea. However, it is always advisable to consult our experts to get a medical opinion at Yashoda Hospitals before taking any medications.

8. What bacteria does Bactrim cover?

  • Shigellosis causing Shigella sp.
  • Pneumonia causing Streptococcus pneumoniae.
  • Typhoid causing Salmonella typhi.
  • Paratyphoid causing Salmonella paratyphi.
  • Staphylococcus sp. (including MRSA strains).
  • Plague causing Yersinia pestis.
  • Cholera causing Vibrio cholerae.
  • Toxoplasma sp.
  • Klebsiella sp. that causes pneumonia, bacteremia, UTI, meningitis, etc.

9. What should I eat when taking Bactrim?

One can consume Bactrim with or without food. If symptoms of diarrhea occur, food or milk is to be taken. It is essential to drink plenty of water or liquids as Bactrim can cause kidney stones. Avoid taking any sulfate-containing foods or potassium supplements like lite salts. One should also avoid propylene glycol-containing foods like soft drinks, medicines, and certain processed foods.

10. What skin infections does Bactrim treat?

Bactrim is especially effective against numerous complicated skin infections like boils (skin abscess), cellulitis (red and painful skin rash in particular areas), folliculitis (infection at the hair follicles), impetigo (hey-colored blisters on the skin), paronychia (infection on the skin around nails). Bactrim effectively kills methicillin-resistant Staphylococcus aureus (MRSA) bacteria, which is resistant to various antibiotics.



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      Disclaimer: The information provided herein is accurate, updated and complete as per the best practices of the Company. Please note that this information should not be treated as a replacement for physical medical consultation or advice. We do not guarantee the accuracy and the completeness of the information so provided. The absence of any information and/or warning to any drug shall not be considered and assumed as an implied assurance of the Company. We do not take any responsibility for the consequences arising out of the aforementioned information and strongly recommend you for a physical consultation in case of any queries or doubts.