Before Using

Drug information provided by: Merative, Micromedex®

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of sulfamethoxazole and trimethoprim combination in children 2 months of age and older. Because of the toxicity of the combination of sulfamethoxazole and trimethoprim, use in infants younger than 2 months of age is not recommended.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of sulfamethoxazole and trimethoprim combination in the elderly. However, elderly patients are more likely to have a folate deficiency, age-related kidney or liver problems, and may be more likely to experience unwanted side effects (eg, severe skin rash, increased potassium in the body, or problems with blood clotting or the immune system). There may be an adjustment in the dose for elderly patients receiving sulfamethoxazole and trimethoprim combination.

Breastfeeding

Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Dofetilide
  • Levomethadyl
  • Methenamine

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Acecainide
  • Acenocoumarol
  • Ajmaline
  • Amiloride
  • Amiodarone
  • Amitriptyline
  • Amoxapine
  • Aprindine
  • Arsenic Trioxide
  • Astemizole
  • Azathioprine
  • Azilsartan
  • Azilsartan Medoxomil
  • Azimilide
  • Benazepril
  • Bretylium
  • Candesartan Cilexetil
  • Captopril
  • Ceritinib
  • Chloral Hydrate
  • Chloroquine
  • Chlorpromazine
  • Cholera Vaccine, Live
  • Clarithromycin
  • Cyclosporine
  • Desipramine
  • Dibenzepin
  • Digoxin
  • Disopyramide
  • Dolasetron
  • Doxepin
  • Dronedarone
  • Droperidol
  • Enalapril
  • Enalaprilat
  • Enflurane
  • Eplerenone
  • Eprosartan
  • Erythromycin
  • Flecainide
  • Fluconazole
  • Fluoxetine
  • Foscarnet
  • Fosinopril
  • Fosphenytoin
  • Gemifloxacin
  • Glyburide
  • Halofantrine
  • Haloperidol
  • Halothane
  • Hydroquinidine
  • Ibutilide
  • Imipramine
  • Irbesartan
  • Isoflurane
  • Isradipine
  • Leucovorin
  • Lidoflazine
  • Lisinopril
  • Lorcainide
  • Losartan
  • Mefloquine
  • Mercaptopurine
  • Methotrexate
  • Moexipril
  • Nortriptyline
  • Octreotide
  • Olmesartan Medoxomil
  • Pentamidine
  • Perindopril
  • Phenytoin
  • Pirmenol
  • Porfimer
  • Prajmaline
  • Probucol
  • Procainamide
  • Prochlorperazine
  • Propafenone
  • Pyrimethamine
  • Quinapril
  • Quinidine
  • Ramipril
  • Risperidone
  • Sapropterin
  • Sematilide
  • Sertindole
  • Sotalol
  • Spiramycin
  • Spironolactone
  • Sultopride
  • Tedisamil
  • Telithromycin
  • Telmisartan
  • Trandolapril
  • Triamterene
  • Trifluoperazine
  • Trimipramine
  • Valsartan
  • Warfarin
  • Zofenopril
  • Zotepine

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Acetohexamide
  • Amantadine
  • Aminolevulinic Acid
  • Anisindione
  • Didanosine
  • Repaglinide
  • Rifabutin
  • Rosiglitazone
  • Tolbutamide

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

  • Ethanol

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Alcohol abuse, history of or
  • Folate (vitamin B9) deficiency or
  • HIV or AIDS or
  • Kidney disease or
  • Liver disease or
  • Malabsorption syndrome (difficulty of absorbing food in the body) or
  • Malnutrition state (nutrition disorder) or
  • Slow acetylator—Use with caution. May have an increased chance of serious side effects.
  • Anemia, megaloblastic (caused by low levels of folic acid in the body) or
  • Drug-induced thrombocytopenia (low platelets in the blood) after using this medicine or
  • Kidney disease, severe or
  • Liver disease, severe—Should not be used in patients with these conditions.
  • Asthma or
  • Diabetes or
  • Hyperkalemia (high potassium in the blood) or
  • Hyponatremia (low sodium in the blood) or
  • Porphyria (enzyme problem) or
  • Severe allergies or
  • Thyroid problems—Use with caution. May make these conditions worse.
  • Glucose-6-phosphate dehydrogenase (G6PD) deficiency (an enzyme problem)—May cause hemolytic anemia (blood disorder) in patients with this condition.
  • Streptococcal infection (group A β-hemolytic)—Sulfonamides should not be used in patients with this condition.

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Portions of this document last updated: April 01, 2024

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