Presentation and Status in Health Basket
This drug is not recommended for use in infants less than 2 months of age.
Urinary Tract Infections and Shigellosis in Adults and Children, Acute Otitis Media in Children:
Adults: 1 “Resprim Forte” Tablet, 2 “Resprim” Tablets, or 4 teaspoonfuls of pediatric suspension, every 12 hours. Treatment of shigellosis should be continued for 5 days. Treatment of urinary tract infections should be continued for 10-14 days.
Children: The recommended dosage is 8 mg/kg body weight/day trimethoprim and 40 mg/kg body weight/day sulfamethoxazole, administered in 2 divided doses.
Children weight 10 kg: 1 teaspoonsful (5 ml) every 12 hours.
Children weight 20 kg: 2 teaspoonsful (10 ml) every 12 hours.
Children weight 30 kg: 3 teaspoonsful (15 ml) every 12 hours.
Children weight 40 kg: 4 teaspoonsful (20 ml) every 12 hours.
Treatment of shigellosis should be continued for 5 days. Treatment of urinary tract infections or acute otitis media should be continued for 10 days.
Acute Exacerbations of Chronic Bronchitis in Adults: 1 “Resprim Forte” Tablet, 2 “Resprim” Tablets or 4 teaspoonfuls of pediatric suspension every 12 hours, for 14 days.
Pneumocystis Carinii Pneumonitis in Children: The recommended dosage is 20 mg/kg body weight/day trimethoprim and 100 mg/kg body weight/day sulfamethoxazole, administered in equally divided doses every 6 hours for 14 days.
Children weight 8 kg: 1 teaspoonsful (5 ml) every 6 hours.
Children weight 16 kg: 2 teaspoonsful (10 ml) every 6 hours.
Children weight 24 kg: 3 teaspoonsful (15 ml) every 6 hours.
Children weight 32 kg: 4 teaspoonsful (20 ml) every 6 hours.
Renal Impairment: For patients with creatinine clearance greater than 30 ml/min the full recommended dosage may be administered. Dosage should be reduced to half the usual dose in patients with creatinine clearance between 30-15 ml/min. It is not recommended in patients with creatinine clearance less than 15 ml/min.
Upper and lower respiratory tract infections, urinary tract infections, genital tract infections, gastro-intestinal tract infections, haemophilus influenza and proteus species bacteria infections.
Known hypersensitivity to trimethoprim or sulfonamides or to any other ingredient of the preparation. Patients showing marked liver parenchymal damage. Patients with severe renal insufficiency where repeated measurements of the plasma concentration cannot be performed. Cotrimoxazole is contraindicated in pregnancy at term, during nursing, in premature babies and during the first 2 months of life. Documented megaloblastic anemia due to folate deficiency.
Sulfonamide-associated deaths, although rare, have occurred due to severe reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia and other blood dyscrasias and hypersensitivity of the respiratory tract. The preparation should be discontinued at the first appearance of skin rash, or any sign of adverse reaction. An adequate urinary output should be maintained at all times. Evidence of crystalluria in vivo is rare, although sulphonamide crystals have been noted in cooled urine from treated patients. In patients suffering from malnutrition the risk may be increased. Regular monthly blood counts are advisable when the product is given for long periods, or to folate deficient patients or to the elderly, since there exists a possibility of asymptomatic changes in hematological laboratory indices due to lack of available folate. These changes may be reversed by administration of folinic acid (5 to 10 mg/day) without interfering with the antibacterial activity. Trimethoprim has been noted to impair phenylalanine metabolism but this is of no significance in phenylketonuric patients on appropriate dietary restriction. Close monitoring of serum potassium and sodium is warranted in patients at risk of hyperkalemia and hyponatremia. The combination of antibiotics in Resprim should only be used where, in the judgement of the physician, the benefits of treatment outweigh any possible risks; consideration should be given to the use of a single effective antibacterial agent
Streptococcal Pharyngitis: Do not use to treat streptococcal pharyngitis. Patients with group A β-hemolytic streptococcal tonsillopharyngitis have a greater incidence of bacteriologic failure with this combination than with penicillin.
Hematological Effects: Hematological hypersensitivity reactions have been reported with sulfonamides, and rarely with trimethoprim, especially when used in large doses and/or for prolonged periods. Clinical signs such as sore throat, fever, pallor, purpura or jaundice may be early indications of serious blood disorders. If any of these signs are noted, a complete blood count should be performed. If a significant reduction in the count of any formed blood element is found, the drug should be discontinued. Except under careful supervision this product should not be given to patients with serious hematological disorders. Cotrimoxazole has been given to patients receiving cytotoxic therapy with little or no additional effect on the bone marrow or peripheral blood.
Use in the Treatment of and Prophylaxis for Pneumocystis Carinii Pneumonia in Patients with Acquired Immunodeficiency Syndrome (AIDS): AIDS patients may not tolerate or respond to cotrimoxazole in the same manner as non-AIDS patients.The incidence of side effects, particularly rash, fever, leukopenia and elevated aminotransferase (transaminase) values, with cotrimoxazole therapy in AIDS patients who are being treated for Pneumocystis carinii pneumonia has been reported to be greatly increased compared with the incidence normally associated with the use of cotrimoxazole in non-AIDS patients.The incidence of hyperkalemia appears to be increased in AIDS patients receiving cotrimoxazole. Adverse effects are generally less severe in patients receiving cotrimoxazole for prophylaxis. A history of mild intolerance to cotrimoxazole in AIDS patients does not appear to predict intolerance of subsequent secondary prophylaxis. However, if a patient develops skin rash or any sign of adverse reaction, therapy with cotrimoxazole should be reevaluated. High dosage of trimethoprim, as used in patients with Pneumocystis carinii pneumonia, Induces a progressive but reversible increase of serum potassium concentrations in a substantial number of patients. Even treatment with recommended doses may cause hyperkalemia when trimethoprim is administered to patients with underlying disorders of potassium metabolism, with renal insufficiency, or if drugs known to induce hyperkalemia are given concomitantly. Close monitoring of serum potassium is warranted in these patients.
During treatment,adequate fluid intake and urinary output should be ensured to prevent crystalluria. Patients who are “slow acetylators” may be more prone to idiosyncratic reactions to sulfonamides.
Use in Pediatrics: The preparation is contraindicated for use in infants less than 2 months of age.
Use in the Elderly: There may be an increased risk of severe adverse reactions in elderly patients, particularly when complicating conditions exist (e.g. impaired kidney and/or liver function), or other drugs are being used concomitantly. Severe skin reactions, generalized bone marrow suppression, or a specific decrease in platelets (with or without purpura) are the most frequently reported severe adverse reactions in elderly patients. In patients concurrently receiving certain diuretics, primarily thiazides, an increased incidence of thrombocytopenia with purpura has been reported. Appropriate dosage adjustments should be made for patients with impaired kidney function. For full details see prescribing information.
Effects on ability to drive and use machines: There have been no studies to investigate the effect of cotimoxazole on driving performance or the ability to operate machinery. Further a detrimental effect on such activities cannot be predicted from the pharmacology of the drug. Nevertheless the clinical status of the patient and the adverse events profile of the product should be borne in mind when considering the patients ability to operate machinery.
Gastrointestinal disturbances and allergic skin reactions, hepatitis, leukopenia, agranulocytosis, thrombocytopenia, methemo-globinemia, aplastic anemia, renal failure, interstital nephritis, BUN and serum creatinine elevation, toxic nephrosis with oliguria and anuria and crystalluria. Aseptic meningitis, convulsions, peripheral neuritis, ataxia, vertigo, tinnitus, headache, hallucinations, depression, apathy, nervousness, arthralgia and myalgia, pulmonary infiltrates, weakness, fatigue, insomnia.
See prescribing information for full details.
Sulfamethoxazole/ Warfarin: Cotrimoxazole has been shown to potentiate the anticoagulant activity of warfarin via stereo-selective inhibition of its metabolism Sulfamethoxazole may displace warfarin from plasma-albumin protein-binding sites in vitro. Thus cotrimoxazole may prolong the prothrombin time of patients who are receiving warfarin. This interaction should be kept in mind when the drug is given to patients on anticoagulant therapy, and the coagulation time should be reassessed.
Sulfamethoxazole/ Sulfonylureas: The hypoglycemic response to sulfonylurea oral antidiabetic agents may be increased due to their displacement from protein binding sites.
Sulfamethoxazole/ Methenamine: In acid urine, methenamine breaks down into formaldehyde which may form an insoluble precipitate with sulfamethoxazole and may also increase the risk of crystalluria. Avoid concurrent use. Sulfamethoxazole/ Methotrexate: Methotrexate may be displaced from protein binding sites, with increase in its free plasma levels, leading to megaloblastic changes. It is therefore recommended that caution be exercised if these agents are to be administered concurrently. The hematological status of the patient should be closely monitored, and either or both agents may have to be discontinued if anemia occurs. The administration of folic acid may be considered. Sulfamethoxazole/ Penicillins: Since bacteriostatic drugs may interfere with the bactericidal effect of penicillins in the treatment of meningitis, or in other situations where a rapid bactericidal effect is necessary, it is best to avoid concurrent therapy.
Sulfamethoxazole/ Zidovudine: Sulfonamides may completely inhibit the hepatic glucuronidation and decrease the clearance of zidovudine. Concurrent use should be avoided since the toxicity of zidovudine may be potentiated. Concomitant treatment may also increase the risk of hematological adverse reactions to cotrimoxazole.
Sulfamethoxazole/ Photosensitizing Medications: Caution in the concurrent use of these medicines with sulfonamides is recommended, because of the possible additive photosensitizing effects.
Sulfamethoxazole/Indomethacin: Increased sulfamethoxazole blood levels may occur in patients who are receiving indomethacin.
Trimethoprim/ Folate Antagonists: Concurrent use, or use of trimethoprim between courses of other folic acid antagonists, whether antineoplastics (e.g. methotrexate) or antimalarials (e.g. pyrimethamine), is not recommended because of the possibility of megaloblastic anemia. Occasional reports suggest that patients receiving pyrimethamine at doses in excess of 25 mg weekly may develop megaloblastic anemia should cotrimoxazole be prescribed concurrently. Trimethoprim/ Rifamipicin: Concurrent use may significantly increase the elimination and shorten the serum half-life of trimethoprim.
Trimethoprim/Drugs That Form Cations at Physiological pH: When trimethoprim is administered simultaneously with drugs that form cations at physiological pH, and are also partly excreted by active renal secretion (eg. procainamide, amantadine), there is the possibility of competitive inhibition of this process which may lead to an increase in plasma concentration of one or both of the drugs.
Trimethoprim/Digoxin: Concomitant use of trimethoprim with digoxin has been shown to increase plasma digoxin levels in a proportion of elderly patients.
Cotrimoxazole/Diuretics: In elderly patients concurrently receiving diuretics, mainly thiazides, there appears to be an increased risk of thrombocytopenia with or without purpura.
Cotrimoxazole/Lamivudine: Administration of trimethoprim/sulfamethoxazole 160mg/800mg causes a 40% increase in lamivudine exposure because of the trimethoprim component. Lamivudine has no effect on the pharmacokinetics of trimethoprim or sulfamethoxazole.
Cotrimoxazole/Drugs That Cause Hyperkalemia: Caution should be exercised in patients taking any other drugs that can cause hyperkalemia.
Cotrimoxazole/ Phenytoin: Cotrimoxazole may inhibit phenytoin metabolism, resulting in a prolonged half-life and excessive phenytoin effect (increased incidence of nystagmus, ataxia or other toxic signs).
Cotrimoxazole/Cyclosporin: Reversible deterioration in renal function has been observed in patients treated with cotrimoxazole and cyclosporin following renal transplantation.
Cotrimoxazole/Tricyclic Antidepressants: The efficacy of tricyclic antidepressants can decrease when coadministered with cotrimoxazole.
Cotrimoxazole/Amantadine: In the literature,a single case of toxic delirium has been reported after concomitant intake of cotrimoxazole and amantadine.
Cotrimoxazole/Angiotensin Converting Enzyme Inhibitors (ACE Inhibitors) In the literature, 3 cases of hyperkalemia in elderly patients have been reported after concomitant intake of cotrimoxazole and an angiotensin converting enzyme inhibitor.
Pregnancy and Lactation
Pregnancy: Because trimethoprim and sulfamethoxazole may interfere with folic acid metabolism, the drug should be used during pregnancy only if the potential benefits to the mother outweigh the possible risks to the fetus. There are not any adequate data from the use of this product in pregnant women. Case-control studies have shown that there may be an association between exposure to folate antagonists and birth defects in humans. Trimethoprim is a folate antagonist and, in animal studies, both agents have been shown to cause foetal abnormalities . Resprim should not be used in pregnancy, particularly in the first trimester, unless clearly necessary. Folate supplementation should be considered if Resprim is used in pregnancy. Sulfamethoxazole competes with bilirubin for binding to plasma albumin. As significantly maternally derived drug levels persist for several days in the newborn, there may be a risk of precipitating or exacerbating neonatal hyperbilirubinaemia, with an associated theoretical risk of kernicterus, when this product is administered to the mother near the time of delivery. This theoretical risk is particularly relevant in infants at increased risk of hyperbilirubinaemia, such as those who are preterm and those with glucose-6-phosphate dehydrogenase deficiency.
Breastfeeding: Trimethoprim and sulfamethoxazole are excreted into breast milk. Administration of cotrimoxazole should be avoided in late pregnancy and in lactating mothers where the mother or infant has, or is at particular risk of developing, hyperbilirubinemia. Additonally, administration of cotrimoxazole should be avoided in infants younger than eight weeks in view of the predisposition of young infants to hyperbilirubinaemia.
Acute: Signs and symptoms of overdose reported with sulfonamides include anorexia, colic nausea, vomiting, dizziness, headache, drowsiness and unconsciousness. Pyrexia, hematuria and crystalluria may be noted. Blood dyscrasias and jaundice are potential late manifestations of overdose. Signs of acute overdose with trimethoprim include nausea, vomiting, dizziness, headache, mental depression, confusion and bone marrow depression.
Chronic: Use of cotrimoxazole in high doses and/or for extended periods of time may cause bone marrow depression. This is manifested as thrombocytopenia, leukopenia and/or megaloblastic anemia.
Treatment: Treatment includes the institution of gastric lavage or emesis, forcing oral fluids, and the administration of intravenous fluids if urine output is low and renal function is normal. Acidification of the urine will increase renal elimination of trimethoprim. The patient should be monitored with blood counts and appropriate blood chemistries, including electrolytes. If signs of bone marrow depression occur, the patient should be given leucovorin 5-15 mg daily, until normal hematopoiesis is restored. Specific therapy should be instituted if jaundice occurs. Peritoneal dialysis is not effective, and hemodialysis is only moderately effective in eliminating trimethoprim and sulfamethoxazole