bactrim

BACTRIM & BACTRIM DS

Complete information on including dosage, side effects, interactions and pregnancy & breast feeding warnings for patient and professional use.

Overview and uses

Bactrim and Bactrim DS

Brand name and active pharmaceutical ingredient:

  • Bactrim – Sulfamethoxazole 400 mg + Trimethoprim 80 mg.
  • Bactrim DS (double strength) – Sulfamethoxazole 800 mg + Trimethoprim 160 mg.

Indication (uses): Bactrim tablets should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria.

  • Urinary tract infections due to susceptible strains like Escherichia coli, Klebsiellaspecies, Enterobacter species, Morganella morganii, Proteus mirabilis and Proteus vulgaris.
  • Acute otitis media in pediatric patients due to susceptible strains ofStreptococcus pneumoniae or Haemophilus influenza.
  • Acute exacerbations of chronic bronchitis due to susceptible strains ofStreptococcus pneumoniae or Haemophilus influenzae.
  • For the treatment of chancroid, but only as a third choice inexpensive alternative.
  • Shigellosis caused by Shigella flexneriand Shigella sonnei.
  • For the treatment and prophylaxis of Pneumocystis jirovecipneumonia in individuals who are immune suppressed and considered to be at an increased risk of developing Jiroveci pneumonia.
  • For the treatment of traveler’s diarrhea in adults due to susceptible strains of enterotoxigenic Coli.

Pharmacological classification: cotrimoxazole (fixed dose combination of Sulfamethoxazole and Trimethoprim is known as cotrimoxazole) anti bacterial.

Brand names: Gantanol, Bactrim.

Dosage form:

  • Available as tablets and double strength tablets.

Mechanism of action:

Sulfamethoxazole inhibits the formation of dihydrofolate from PABA by inhibiting folic acid synthase. Trimethoprim inhibits the formation of tetrahydrofolate by inhibiting dihydrofolate reductase. Since sulfonamides are structurally similar to PABA, they inhibit the union of PABA with pteridine residue to form dihydropteroic acid which conjugates with glutamic acid to produce dihydrofolic acid. Also, being structurally similar to PABA, sulfonamides may get directly incorporated into the bacterial cell to form an altered folate which is metabolically injurious. Individually, both the drugs are bacteriostatic. But when combined, the combination of this two drugs have bactericidal effect.

Dosage

Dosage (for adults):

  • For urinary tract infections:
    • 1 tablet of Bactrim DS or 2 tablets of Bactrim every 12 hours for 10 – 14 days.
  • For shigellosis:
    • 1 tablet of Bactrim DS or 2 tablets of Bactrim every 12 hours for 5 days.
  • Acute exacerbation of chronic bronchitis:
    • 1 tablet of Bactrim DS or 2 tablets of Bactrim every 12 hours for 14 days.
  • For traveler’s diarrhea:
    • 1 tablet of Bactrim DS or 2 tablets of Bactrim every 12 hours for 5 days.
  • For the treatment of Pneumocystis jirovecipneumonia (for adults and pediatric patients):
    • 75 to 100 mg/kg Sulfamethoxazole + 15 to 20 mg/kg Trimethoprim in 24 hours in equally divided dose every 6 hours for 14 to 21 days.
    • Dose calculation based on body weight:
      • Not recommended in patients with body weight less than 16 kg.
      • 16 kg or more but less than 24 kg – 1 Bactrim tablet every 6 hours.
      • 24 kg or more but less than 32 kg – 1.5 (one and a half) tablet of Bactrim every 6 hours.
      • 32 kg or more but less than 40 kg – 2 tablets of Bactrim or 1 tablet of Bactrim DS every 6 hours.
      • 40 kg or more but less than 48 kg – 2.5 (two and a half) tablet of Bactrim every 6 hours.
      • 48 kg or more but less than 64 kg – 3 tablets of Bactrim or 1.5 (one and a half) tablet of Bactrim DS every 6 hours.
      • 64 kg or more but less than 80 kg – 4 tablets of Bactrim or 2 tablets of Bactrim DS every 6 hours.
      • 80 kg or more – 5 tablets of Bactrim or 2.5 (two and a half) tablet of Bactrim DS every 6 hours.
    • For the prophylaxis of Pneumocystis jirovecipneumonia:
      • 1 tablet of Bactrim DS daily.
    • For the treatment of Traveler’s diarrhea in adults:
      • I tablet of Bactrim DS or 2 tablets of Bactrim every 12 hours for 5 days.

Dosage (for pediatric patients):

  • For urinary tract infections and acute otitis media:
    • 20 mg/kg of Sulfamethoxazole and 4 mg/kg of Trimethoprim every 12 hours for 10 days.
  • For shigellosis:
    • 20 mg/kg of Sulfamethoxazole and 4 mg/kg of Trimethoprim every 12 hours for 5 days.
    • Dose calculation based on body weight in children with 2 months of age or older:
      • Not recommended for body weight less than 20 kg.
      • 20 kg or more but less than 30 kg body weight: 1 tablet of Bactrim.
      • 30 kg or more but less than 40 kg body weight: 1.5 (one and a half) tablet of Bactrim.
      • 40 kg or more: 2 tablets of Bactrim or 1 tablet of Bactrim DS.
    • For the prophylaxis of Pneumocystis jirovecipneumonia:
      • Recommended dose is 750 mg/m2/day Sulfamethoxazole with 150 mg/m2/day Trimethoprim given orally in equally divided doses twice a day, on 3 consecutive days per week. The total daily dose should not exceed 1600 mg Sulfamethoxazole and 320 mg Trimethoprim.
      • Guidelines to achieve the above mentioned dose in children on the basis of body surface area is mentioned below:
        • Not recommended in children with body surface area less than 0.53 m2.
        • Body surface area more than 0.53 m2 but less than 1.06 m2 – 0.5 (half) tablet of Bactrim every 12 hours.
        • Body surface area more than 1.06 m2 – 1 tablet of Bactrim every 12 hours.

Renal dose adjustment:

  • Creatinine clearance more than 30 ml/min – usual standard dosage.
  • Creatinine clearance less than 30 but more than or equal to 15 ml/min – half the dose of standard dosage.
  • Creatinine clearance below 15 ml/min – not recommended.

Side effects or unwanted effects:

  • The most common adverse effects reported with Sulfamethoxazole and Trimethoprim combination are nausea, vomiting, urticaria, skin rash and anorexia. The severity of these adverse effects is more in patients with HIV or AIDS.
  • Occurrence of severe skin reactions, decreased platelets accompanied with or without purpura, elevated potassium levels and bone marrow suppression is more common in elderly patients.
  • Hypersensitivity reaction including urticarial rash (most common), allergic myocarditis, arthralgia, epidermal necrolysis, erythema multiforme, exfoliative dermatitis, Stevens – Johnson syndrome, urticaria, serum sickness, photo sensitization and generalized skin eruptions.
    • Consult your doctor as soon as possible if you observe skin rash, red or purple colored skin rash, facial swelling, swelling of the tongue, hives on the skin, joint pain, a painful red area on the skin that spreads quickly, peeling of the skin without blistering, fever, shortness of breath during exercise at first and then at night time while lying down, abnormal heart beat, light headedness, sharp or stabbing chest pain and fatigue are some of the symptoms. This may require immediate medical attention and discontinuation of the therapy.
  • Gastrointestinal side effects include nausea, vomiting, abdominal pain, diarrhea, anorexia, pancreatitis and stomatitis.
    • Ask your pharmacist to recommend a suitable medicine and consult your doctor.
  • Occurrence of hepatitis and jaundice, though rare cannot be ruled out.
    • Nausea, stomach pain, dark colored urine, yellowing of the skin and whites of the eye, light or clay colored stools, fever and unusual tiredness are some of the symptoms. Consult your doctor as soon as possible. This may require discontinuation of the treatment with sulfadiazine.
  • Aplastic anemia, hemolytic anemia, hypoprothrombinemia, leucopenia, purpura and agranulocytosis.
    • Purple colored spots under skin, sudden fever, chills, sore throat, weakness in limbs, mouth ulcers, bleeding gums, easy bruising and prolonged bleeding are some of the symptoms of the above mentioned condition. Consult your doctor as soon as possible as some of the above mentioned conditions are serious and life threatening.
  • Tremulousness, delirium and disorientation have been frequently reported
    • Shaking of a body part or even full body, anxiety, fear, hallucinations, irritability, rapid and unpredictable mood swings, difficulty in reading, writing, recalling or speaking of words are some of the symptoms of the above mentioned condition. Consult your doctor as soon as possible.
  • Occurrence of frank psychosis is rare.
  • Ataxia, convulsions, hallucinations, headache, insomnia, mental depression, peripheral neuritis, tinnitus and vertigo have also been reported.
  • Crystalluria, lupus periarteritis nodosa, toxic nephrosis with oliguria and anuria have also been reported.
  • Occurrence of hypoglycemia has also been reported with sulfadiazine use.
  • Kernicterus may be precipitated in new born, commonly observed with premature born babies.
  • Occurrence of hypersensitivity or anaphylaxis with Trimethoprim use, though rare but cannot be neglected.
    • Nausea, vomiting, diarrhea, dizziness, abdominal pain, fainting, low blood pressure, rapid heartbeat, tightness of the throat, troubled breathing, hives or urticaria are some of the symptoms.
    • Consult your doctor as soon as possible if you observe any of the above mentioned symptoms. This may require immediate medical attentions and probably discontinuation of the therapy.
  • Occurrence of cholestatic jaundice is also rare with Trimethoprim use.
    • Itchiness, dark stools, pale coloured urine, yellowing of the skin and whites of the eye are some of the symptoms.
    • Consult your doctor as soon as possible if you observe any of the above mentioned symptoms. This may require immediate medical attentions and probably discontinuation of the therapy.
  • Nausea, vomiting, glossitis, sore mouth, abdominal pain and epigastric distress are some of the common side effects observed with Trimethoprim use.
    • Sore and tender tongue, difficulty in speaking, swallowing or chewing, swelling of the tongue and tongue color changes are some of the symptoms of glossitis. Consult your doctor as this may require an antibiotic or steroid.
  • Occurrence of maculopapular, morbilliform and pruritic skin rash is common with Trimethoprim use.
    • Small red spots on skin, fever, headache, nausea and vomiting, measles like rash, difficulty in breathing, severe head or neck pain, swelling of the face or extremities are some of the symptoms.
    • Consult your doctor as soon as possible if you observe any of the above mentioned symptoms along with a skin rash. This may require immediate medical attention.

Pregnancy and breast feeding warnings

Pregnancy: Category D, which means there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

Nursing:

  • Sulfamethoxazole – Trimethoprim (Bactrim) is secreted in human breast milk.
  • Sulfamethoxazole – Trimethoprim (Bactrim) combination use is contraindicated in a mother nursing a G6PD deficient breast feeding infant.
  • Sulfamethoxazole – Trimethoprim (Bactrim) use in mothers nursing a premature baby or a baby with jaundice should be avoided as safety profile for Sulfamethoxazole – Trimethoprim (Bactrim) use in such cases is not established.
  • Sulfamethoxazole can be used in a mother nursing a healthy and full term baby.

Interactions

Drug – drug interactions:

  • Concomitant use of Sulfamethoxazole – Trimethoprim (Bactrim) with indomethacin, probenecid or aspirin (including all salicylates) may worsen the side effects of Sulfamethoxazole.
  • Anti-coagulants like warfarin increases the risk of bleeding when co-administered with Sulfamethoxazole – Trimethoprim (Bactrim).
  • Side effects of methotrexate and thiazide diuretics like Hydrochlorothiazide, Benzthiazide, Hydroflumethiazide and Clopamide may be increased when co-administered with Sulfamethoxazole – Trimethoprim (Bactrim).
  • Sulfonylurea’s like Glipizide, Glimepiride and Glyburide may increase the risk of low blood sugar when co-administered with Sulfamethoxazole – Trimethoprim (Bactrim).
  • Consult your doctor before taking Sulfamethoxazole – Trimethoprim (Bactrim) with clozapine, cyclosporine, anisindione, sodium nitrite, methenamine, lomitapide, mipomersen and live cholera vaccine.
  • Use of Sulfamethoxazole – Trimethoprim (Bactrim) with angiotensin converting enzyme (ACE) inhibitors like captopril, enalapril, lisinopril, perindopril, fosinopril, trandolapril, ramipril, imidapril, benazepril and quinapril is contraindicated as it may cause or worsen the pre-existing hyperkalemia.
  • Use of Sulfamethoxazole – Trimethoprim (Bactrim) with angiotensin receptor blockers like losartan, candesartan, irbesartan, valsartan, telmisartan and fimasartan is contraindicated as it may cause or worsen the pre-existing hyperkalemia.
  • Use of Sulfamethoxazole – Trimethoprim (Bactrim) with anti fungals like ketoconazole, fluconazole and itraconazole is contraindicated as it may cause or worsen the pre-existing hyperkalemia.
  • Concomitant use of Sulfamethoxazole – Trimethoprim (Bactrim) and cyclosporine, spironolactone, digoxin, penicillin G, pentamidine, tacrolimus, succinylcholine, heparin, triamterene and amilioride is contraindicated as it may cause or worsen the pre-existing hyperkalemia.
  • Use of Sulfamethoxazole – Trimethoprim (Bactrim) with beta blockers like atenolol, acebutolol, propranolol, sotalol, timolol, pindolol, labetalol, carvedilol, metoprolol, bisoprolol, esmolol, betaxolol, celiprolol and nebivolol is contraindicated as it may cause or worsen the pre-existing hyperkalemia.
  • Dofetilide use with Sulfamethoxazole – Trimethoprim (Bactrim) is contraindicated as it imposes a potential for severe heart problems.
  • Use of Sulfamethoxazole – Trimethoprim (Bactrim) or any combination containing Trimethoprim should be done with caution when used with NSAID (non steroidal anti inflammatory diseases) as these drugs are known to cause water and salt retention.

Drug-food interactions:

  • Sulfamethoxazole – Trimethoprim (Bactrim) combination can be taken with or without food.
  • Avoid consuming alcohol when taking Sulfamethoxazole – Trimethoprim combination (Bactrim).

Click here to go to Bactrim and Bactrim DS forums.

Note: The sole purpose of every information shared on this article is to bring awareness. Do not use this information as a medical advice or prescription advice or as a tool for the treatment, diagnosis or prevention of the disease.

By |2018-12-29T07:16:12+00:00May 2nd, 2017|medicines|Comments Off on bactrim

About the Author:

B. Pharm (K.L.E. society's S.V.V. Patil College of Pharmacy, Bengaluru) M. Pharm (Maharishi Arvind Institute of Pharmacy, Jaipur)

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