Tiemonium Methylsulfate

Treatment of enteritis; treatment of Pneumocystis carinii pneumonia; treatment of severe or complicated UTIs caused by susceptible strains of bacteria.

-Treatment of acute otitis media and acute exacerbations of chronic bronchitis; treatment of traveler’s diarrhea; treatment and prophylaxis of P. carinii pneumonia; Shigella enteritis; UTIs caused by susceptible strains of bacteria.

-Treatment of cholera, salmonella-type infections, and nocardiosis; prevention of recurrent UTIs in women; prophylaxis of bacterial infections in susceptible patients; treatment of acute and chronic bacterial prostatitis; treatment of skin and soft-tissue infections caused by Staphylococcus aureus.

Trimethoprim is contraindicated in individuals hypersensitive to trimethoprim and in those with documented megaloblastic anemia due to folate deficiency.

ACE inhibitors

Hyperkalemia, possibly with cardiac arrhythmias or cardiac arrest, may occur during coadministration.

Amantadine

A case of toxic delirium has been reported after coadministration with sulfamethoxazole/trimethoprim.

Antiarrhythmic agents (eg, amiodarone, bretylium, disopyramide, dofetilide, procainamide, quinidine, sotalol), arsenic trioxide, chlorpromazine, cisapride, dolasetron, droperidol, mefloquine, mesoridazine, moxifloxacin, pentamidine, pimozide, tacrolimus, thioridazine, ziprasidone

An additive effect of trimethoprim/sulfamethoxazole with other drugs that prolong the QT interval cannot be excluded.

Cyclosporine

May cause decreased therapeutic effect of cyclosporine and increased risk of nephrotoxicity.

Digoxin

Increased digoxin levels may occur.

Diuretics (eg, thiazides)

An increased incidence of thrombocytopenia with purpura has been reported during coadministration.

Indomethacin

Sulfamethoxazole blood levels may be increased.

Methenamine

Methenamine is contraindicated for use with sulfonamides because of the potential of formation of insoluble precipitates in the urine.

Methotrexate

May displace methotrexate from protein-binding sites, thus increasing free methotrexate levels.

Phenytoin

Trimethoprim may inhibit metabolism of phenytoin or other hydantoins.

Procainamide

Trimethoprim may inhibit renal elimination of procainamide and its metabolites.

Sulfones (eg, dapsone)

The plasma concentration of both drugs may be increased.

Sulfonylureas

May increase hypoglycemic response to sulfonylureas because of displacement from protein-binding sites or inhibition of hepatic metabolism.

Tricyclic antidepressants

Efficacy may be decreased.

Vaccines, live

The effectiveness of live vaccines may be decreased.

Warfarin

May cause prolonged PT.

Laboratory Test Interactions

Can interfere with serum methotrexate assay as determined by competitive binding protein technique when bacterial dihydrofolate reductase is used as binding protein. May interfere with Jaffe alkaline picrate reaction assay for creatinine, resulting in overestimations

CNS

Apathy, aseptic meningitis, ataxia, convulsions, depression, fatigue, hallucinations, headache, insomnia, nervousness, peripheral neuritis, vertigo, weakness.

EENT

Tinnitus.

Endocrine

Diuresis, hypoglycemia.

Hematologic

Agranulocytosis, aplastic anemia, eosinophilia, hemolytic anemia, hypoprothrombinemia, leukopenia, megaloblastic anemia, methemoglobinemia, neutropenia, thrombocytopenia.

Hypersensitivity

Allergic myocarditis, anaphylaxis, angioedema, chills, conjunctival and scleral injection, drug fever, erythema multiforme, exfoliative dermatitis, generalized allergic reactions, generalized skin eruptions, Henoch-Schoenlein purpura, periarteritis nodosa, photosensitivity, pruritus, rash, serum sickness–like syndrome, Stevens-Johnson syndrome, systemic lupus erythematosus, toxic epidermal necrolysis, urticaria.

GI

Abdominal pain, anorexia, diarrhea, elevation of serum transaminase and bilirubin, emesis, glossitis, hepatitis (including cholestatic jaundice and hepatic necrosis), nausea, pancreatitis, pseudomembranous enterocolitis, stomatitis, vomiting.

Genitourinary

BUN and serum creatinine elevation, crystalluria and nephrotoxicity in association with cyclosporine, interstitial nephritis, renal failure, toxic nephrosis with oliguria and anuria.

Metabolic

Hyperkalemia.

Musculoskeletal

Arthralgia, myalgia, rhabdomyolysis.

Respiratory

Cough, pulmonary infiltrates, shortness of breath.