Note: This document contains side effect information about sulfamethoxazole / trimethoprim. Some of the dosage forms listed on this page may not apply to the brand name Bactrim.
Applies to sulfamethoxazole / trimethoprim: oral suspension, oral tablet
Other dosage forms:
Along with its needed effects, sulfamethoxazole/trimethoprim may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur while taking sulfamethoxazole / trimethoprim:
Incidence not known
Some side effects of sulfamethoxazole / trimethoprim may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Incidence not known
Applies to sulfamethoxazole / trimethoprim: intravenous solution, oral suspension, oral tablet
The most common side effects were gastrointestinal disturbances (nausea, vomiting, anorexia) and allergic skin reactions (e.g., rash, urticaria).
Effects associated with Pneumocystis jirovecii pneumonia management have included severe hypersensitivity reactions, rash, pyrexia, neutropenia, thrombocytopenia, elevated liver enzymes, hyperkalemia, hyponatremia, and rhabdomyolysis; such effects were very rare.
Although rare, fatalities associated with sulfonamide use have occurred due to severe reactions, including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, other blood dyscrasias, and respiratory hypersensitivity.
Hypoglycemia has been reported in patients using sulfonamides.
Very common (10% or more): Hyperkalemia
Frequency not reported: Anorexia, hypoglycemia, hyponatremia, decreased appetite
Postmarketing reports: Metabolic acidosis
Common (1% to 10%): Nausea, diarrhea
Uncommon (0.1% to 1%): Vomiting
Frequency not reported: Glossitis, stomatitis, pseudomembranous enterocolitis, pancreatitis, emesis, abdominal pain, pseudomembranous colitis, Clostridium difficile-associated diarrhea, constipation, sore mouth
Aseptic meningitis was rapidly reversible when this drug was stopped but recurred in several cases upon re-exposure to either this combination drug or to trimethoprim alone.
Tremor and other neurological manifestations (e.g., ataxia, ankle clonus, apathy) occurred during therapy with this drug in several patients with AIDS; although such effects have also been associated with the underlying disease process, these symptoms resolved within 2 to 3 days after stopping this drug.
Common (1% to 10%): Headache
Frequency not reported: Aseptic meningitis, convulsions/seizures, peripheral neuritis/neuropathy, ataxia, dizziness, vertigo, tinnitus, tremor, other neurological manifestations (e.g., ataxia, ankle clonus, apathy), lethargy, paresthesia, syncope
Common (1% to 10%): Rash
Frequency not reported: Diffuse rash, erythematous rash, maculopapular rash, morbilliform rash, pruritic rash, urticaria, photosensitivity, pruritus, exfoliative dermatitis, fixed drug eruption, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, Henoch-Schonlein purpura, drug reaction with eosinophilia and systemic symptoms (DRESS), generalized skin eruptions, purpura, angioedema, generalized pustular dermatosis, alopecia, allergic/hypersensitivity vasculitis resembling Henoch-Schonlein purpura, erythema nodosum, bullous dermatitis
Common (1% to 10%): Fungal/monilial overgrowth
Frequency not reported: Drug fever, chills, weakness, fatigue, abnormal elevations in alkaline phosphatase, positive lupus erythematous phenomenon, moniliasis
Frequency not reported: Thrombophlebitis, allergic myocarditis, polyarteritis/periarteritis nodosa
Postmarketing reports: QT prolongation (resulting in ventricular tachycardia and torsade de pointes)
Frequency not reported: Leucopenia, neutropenia, thrombocytopenia, bone marrow depression, agranulocytosis, aplastic anemia, hemolytic anemia, megaloblastic anemia, methemoglobinemia, hypoprothrombinemia, eosinophilia, hematological toxicity, hemolysis, pancytopenia, granulocytopenia
Postmarketing reports: Thrombotic thrombocytopenic purpura, idiopathic thrombocytopenic purpura
Severe cases of thrombocytopenia that were fatal or life-threatening have been reported. Thrombocytopenia generally resolved within a week when this drug was discontinued.
Hemolysis has been reported in certain susceptible glucose-6-phosphate deficient patients.
Frequency not reported: Hepatitis, cholestatic jaundice, hepatic necrosis, elevated serum transaminase, elevated bilirubin, hepatic changes, abnormal elevations in serum transaminase levels, jaundice, elevated liver enzymes, disturbance in liver enzymes
Cases of cholestatic jaundice and hepatic necrosis have been fatal.
Jaundice (generally mild and transient) has been reported rarely, often occurring in patients with history of infectious hepatitis.
Frequency not reported: Hypersensitivity, allergic skin reactions, anaphylaxis, serum sickness-like syndrome, generalized allergic reactions, anaphylactic/anaphylactoid reactions, severe hypersensitivity reactions (including associated with P jirovecii pneumonia), serum sickness
Frequency not reported: Local reaction, pain, slight/local irritation, inflammation
Local reaction, pain, and slight irritation were reported infrequently with IV administration.
Frequency not reported: Arthralgia, myalgia, rhabdomyolysis, systemic lupus erythematosus, muscle weakness
Rhabdomyolysis has been reported with this drug, primarily in patients with AIDS.
Frequency not reported: Uveitis, conjunctival and scleral injection/redness/edema, periorbital edema, corneal ring infiltrates, vision problems
Frequency not reported: Depression/mental depression, hallucinations, apathy, nervousness, insomnia, psychotic disorder, confusional state, agitation, anxiety, abnormal behavior, nightmares
Nephrotoxicity has been reported in association with cyclosporine.
Frequency not reported: Renal impairment/failure, interstitial nephritis, tubulointerstitial nephritis and uveitis syndrome, elevated BUN, elevated serum creatinine, toxic nephrosis, renal tubular acidosis, nephrotoxicity, functional kidney changes, abnormal elevations in serum urea, abnormal elevations in serum creatinine, stone formation, tubular necrosis, aggravation of renal disease, azotemia, hyperkalemic renal tubular acidosis, overestimations of normal creatinine values
Frequency not reported: Oliguria, anuria, crystalluria, diuresis, dysuria, hematuria, urgency changes, abnormal elevations in urine protein levels
Diuresis has been reported in patients using sulfonamides.
Frequency not reported: Cough, dyspnea/shortness of breath, pulmonary infiltrates/lung infiltration, epistaxis, eosinophilic/allergic alveolitis, wheezing
Cough, dyspnea, and lung infiltration have been early indicators of respiratory hypersensitivity which, while very rare, has been fatal.
Medically reviewed by BestRx Medical Team Last updated on 1/1/2020.
Source: Drugs.com Bactrim Ds