Septra contains the active ingredients sulfamethoxazole and trimethoprim, in a synthetic antibacterial combination. It is available in double strength (DS) tablets with 800 mg sulfamethoxazole and 160 mg trimethoprim, and in regular tablets with 400 mg sulfamethoxazole and 80 mg trimethoprim for oral administration. Key inactive ingredients include docusate sodium, sodium benzoate, sodium starch glycolate, magnesium stearate, and pregelatinized starch.

How should I use this medication?

Take this medication by mouth. Follow the directions on the prescription label. Shake well before using. Use a specially marked oral syringe, spoon, or dropper to measure each dose. Ask your pharmacist if you do not have one. Household spoons are not accurate. Take your medication at regular intervals. Do not take it more often than directed. Take all of your medication as directed even if you think you are better. Do not skip doses or stop your medication early. Talk to your care team about the use of this medication in children. While this medication may be prescribed for children as young as 2 months for selected conditions, precautions do apply.

Overdosage: If you think you have taken too much of this medicine contact a poison control center or emergency room at once. NOTE: This medicine is only for you. Do not share this medicine with others.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

Where should I keep my medication?

Keep out of the reach of children. Store between 15 and 25 degrees C (59 to 77 degrees F). Protect from light. Keep the container tightly closed. Throw away any unused medication after the expiration date.

NOTE: This sheet is a summary. It may not cover all possible information. If you have questions about this medicine, talk to your doctor, pharmacist, or health care provider.

What side effects may I notice from receiving this medication?

Side effects that you should report to your care team as soon as possible: -Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat -Aplastic anemia—unusual weakness or fatigue, dizziness, headache, trouble breathing, increased bleeding or bruising -Dry cough, shortness of breath or trouble breathing -Fever, rash, swollen lymph nodes, confusion, trouble walking, loss of balance or coordination, seizures -High potassium level—muscle weakness, fast or irregular heartbeat -Liver injury—right upper belly pain, loss of appetite, nausea, light-colored stool, dark yellow or brown urine, yellowing skin or eyes, unusual weakness or fatigue -Low blood sugar (hypoglycemia)—tremors or shaking, anxiety, sweating, cold or clammy skin, confusion, dizziness, rapid heartbeat -Low sodium level—muscle weakness, fatigue, dizziness, headache, confusion -Low thyroid levels (hypothyroidism)—unusual weakness or fatigue, increased sensitivity to cold, constipation, hair loss, dry skin, weight gain, feelings of depression -Rash, fever, and swollen lymph nodes -Redness, blistering, peeling, or loosening of the skin, including inside the mouth -Severe diarrhea, fever -Unusual bruising or bleeding -Unusual vaginal discharge, itching, or odor Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome): -Loss of appetite -Nausea -Vomiting

This list may not describe all possible side effects. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What should I tell my care team before I take this medication?

They need to know if you have any of these conditions: -G6PD deficiency -HIV or AIDS -Kidney disease -Liver disease -Low platelet levels -Low red blood cell levels -Poor nutrition -Stomach or intestine problems, such as colitis -Thyroid disease -An unusual or allergic reaction to sulfamethoxazole, trimethoprim, other medications, foods, dyes, or preservatives -Pregnant or trying to get pregnant -Breast-feeding

What may interact with this medication?

Do not take this medication with any of the following: -Dofetilide This medication may also interact with the following: -Amantadine -Certain medications for blood pressure or heart disease -Certain medications for depression, such as amitriptyline -Certain medications for diabetes, such as glipizide or glyburide -Certain medications that treat or prevent blood clots, such as warfarin -Cyclosporine -Digoxin -Diuretics -Estrogen and progestin hormones -Indomethacin -Methotrexate -Phenytoin -Procainamide -Pyrimethamine -Zidovudine

This list may not describe all possible interactions. Give your health care provider a list of all the medicines, herbs, non-prescription drugs, or dietary supplements you use. Also tell them if you smoke, drink alcohol, or use illegal drugs. Some items may interact with your medicine.

What should I watch for while using this medication?

Tell your care team if your symptoms do not start to get better or if they get worse. Do not treat diarrhea with over the counter products. Contact your care team if you have diarrhea that lasts more than 2 days or if it is severe and watery. This medication may cause serious skin reactions. They can happen weeks to months after starting the medication. Contact your care team right away if you notice fevers or flu-like symptoms with a rash. The rash may be red or purple and then turn into blisters or peeling of the skin. Or, you might notice a red rash with swelling of the face, lips or lymph nodes in your neck or under your arms. This medication can make you more sensitive to the sun. Keep out of the sun. If you cannot avoid being in the sun, wear protective clothing and sunscreen. Do not use sun lamps or tanning beds/booths. Be careful brushing or flossing your teeth or using a toothpick because you may get an infection or bleed more easily. If you have any dental work done, tell your dentist you are receiving this medication.