Sulfameth/trimethoprim 800/160mg Tb

Sulfamethoxazole inhibits bacterial dihydrofolate synthesis by competing with para-aminobenzoic acid (PABA) for incorporation into dihydrofolic acid. Trimethoprim inhibits bacterial dihydrofolate reductase, an enzyme that converts dihydrofolic acid to tetrahydrofolic acid. This sequential blockade of two steps in the bacterial folic acid synthesis pathway results in synergistic bactericidal activity.

Important Side Effects to Report to Your Doctor Immediately

Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you experience any of the following symptoms, seek medical attention right away:

Allergic Reaction: Rash, hives, itching, red, swollen, blistered, or peeling skin with or without fever, wheezing, tightness in the chest or throat, trouble breathing, swallowing, or talking, unusual hoarseness, or swelling of the mouth, face, lips, tongue, or throat.
High Potassium Levels: Abnormal heartbeat, confusion, weakness, lightheadedness, dizziness, numbness or tingling, or shortness of breath.
Low Blood Sugar: Dizziness, headache, drowsiness, weakness, shaking, rapid heartbeat, confusion, hunger, or sweating.
Kidney Problems: Inability to urinate, changes in urine output, blood in the urine, or significant weight gain.
Low Sodium Levels: Headache, difficulty focusing, memory problems, confusion, weakness, seizures, or balance changes.
Lung or Breathing Problems: Shortness of breath, trouble breathing, cough, or fever.
Pancreas Problems (Pancreatitis): Severe stomach pain, severe back pain, or severe nausea and vomiting.
Other Serious Side Effects:
+ Muscle or joint pain
+ Purple patches on the skin or mouth
+ Hallucinations (seeing or hearing things that are not there)
+ Depression or mood changes
+ Abnormal burning, numbness, or tingling sensations
+ Ringing in the ears
+ Swollen glands
+ Chest pain
+ Pale skin
+ Severe dizziness or fainting

Antibiotic-Related Side Effects:

Diarrhea is a common side effect of antibiotics. However, a rare but severe form called C. diff-associated diarrhea (CDAD) may occur, which can lead to life-threatening bowel problems. If you experience stomach pain, cramps, or loose, watery, or bloody stools, seek medical attention immediately.
Before treating diarrhea, consult your doctor.

Rare but Serious Side Effects:

Sulfa Drug Reactions: Although rare, severe and potentially life-threatening effects have occurred with sulfa drugs, including liver problems, blood disorders, and severe skin reactions (Stevens-Johnson syndrome/toxic epidermal necrolysis). If you experience any of the following symptoms, seek medical attention right away:
+ Rash
+ Red, swollen, blistered, or peeling skin
+ Red or irritated eyes
+ Sores in the mouth, throat, nose, or eyes
+ Fever, chills, or sore throat
+ New or worsening cough
+ Extreme fatigue or weakness
+ Bruising or bleeding
+ Signs of liver problems, such as dark urine, fatigue, decreased appetite, nausea, light-colored stools, vomiting, or yellow skin and eyes
Aseptic Meningitis: This medication may increase the risk of a severe brain problem called aseptic meningitis. If you experience any of the following symptoms, seek medical attention right away:
+ Headache
+ Fever
+ Chills
+ Severe nausea and vomiting
+ Stiff neck
+ Rash
+ Sensitivity to light
+ Drowsiness
+ Confusion
Hemophagocytic Lymphohistiocytosis (HLH): A rare but potentially life-threatening immune system problem called HLH has occurred with this medication. If you experience any of the following symptoms, seek medical attention right away:
+ Fever
+ Swollen glands
+ Rash
+ Seizures
+ Confusion or decreased alertness
+ Balance changes
+ Difficulty walking (new or worsening)

Common Side Effects:

Diarrhea
Stomach pain
Nausea
Vomiting
Decreased appetite

If you experience any side effects that bother you or do not go away, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following conditions and situations to ensure safe treatment with this medication:

Any known allergies to this drug, its components, or other substances, including foods and medications. Describe the allergic reaction and its symptoms.
A history of anemia caused by a lack of folic acid.
Presence of kidney disease or liver disease.
Certain health conditions, including:
+ Asthma
+ Porphyria
+ Thyroid disease
+ Folate deficiency
+ Malabsorption
+ Poor nutrition
Long-term alcohol consumption or current use of antiseizure medications.
Previous experience with low platelet counts while taking trimethoprim or sulfa (sulfonamide) drugs.
Concurrent use of the following medications:
+ Amantadine
+ Cyclosporine
+ Dofetilide
+ Indomethacin
+ Leucovorin
+ Methotrexate
+ Pyrimethamine
Recent or current use of the following drugs:
+ Benazepril
+ Captopril
+ Enalapril
+ Fosinopril
+ Lisinopril
+ Moexipril
+ Perindopril
+ Quinapril
+ Ramipril
+ Trandolapril
Use of diuretics (water pills).
For children: If your child is under 2 months of age, do not administer this medication, as it is not recommended for infants younger than 2 months.

This list is not exhaustive, and it is crucial to disclose all your medications (prescription, over-the-counter, natural products, and vitamins) and health conditions to your doctor and pharmacist. They will help you determine the safety of taking this medication with your other treatments and health issues. Never start, stop, or adjust the dosage of any medication without consulting your doctor.

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Your doctor will instruct you on when to have your blood work and other laboratory tests checked. Be aware that this drug may interfere with certain lab tests, so it is crucial to notify all your healthcare providers and laboratory personnel that you are taking this medication.

Do not take this medication for a longer period than prescribed, as this may increase the risk of a second infection. If you have a deficiency of the enzyme glucose-6-phosphate dehydrogenase (G6PD), you may be at a higher risk of developing anemia. This deficiency is more common in individuals of African, South Asian, Middle Eastern, and Mediterranean descent.

If you have diabetes (high blood sugar), it is vital to monitor your blood sugar levels closely while taking this medication. Before consuming alcohol, consult with your doctor to discuss any potential risks. Additionally, this medication may increase your sensitivity to the sun, making you more prone to sunburn. Take necessary precautions when exposed to the sun, and inform your doctor if you experience any unusual sunburn or sensitivity.

In rare cases, this medication can cause a severe and potentially life-threatening reaction, characterized by symptoms such as fever, rash, or swollen glands, along with problems in various organs, including the liver, kidney, blood, heart, muscles and joints, or lungs. If you have any concerns or questions, discuss them with your doctor.

If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects. Women who are pregnant or become pregnant while taking this medication should contact their doctor immediately, as it may harm the unborn baby. If you are breastfeeding, consult with your doctor to discuss any potential risks to your baby.

• Dofetilide (risk of QT prolongation and Torsades de Pointes)
• Methotrexate (severe bone marrow suppression, megaloblastic anemia)

• Warfarin (significantly potentiates anticoagulant effect, increased bleeding risk)
• ACE inhibitors/ARBs (increased risk of hyperkalemia, especially in elderly or renally impaired)
• Phenytoin (increased phenytoin levels, toxicity)
• Digoxin (increased digoxin levels)
• Cyclosporine (decreased cyclosporine levels, increased nephrotoxicity)
• Pyrimethamine (increased risk of megaloblastic anemia)
• Oral Hypoglycemics (sulfonylureas - increased hypoglycemic effect)
• Thiazide diuretics (increased risk of thrombocytopenia with purpura in elderly)

• Amantadine (increased amantadine levels, toxicity)
• Procainamide (increased procainamide levels)
• Rifampin (decreased trimethoprim levels)
• Spironolactone (increased risk of hyperkalemia)
• Potassium-sparing diuretics (increased risk of hyperkalemia)
• Tricyclic antidepressants (increased TCA levels)
• Zidovudine (increased zidovudine levels, hematologic toxicity)

• Oral contraceptives (potential for reduced efficacy, though clinical significance debated)
• Indomethacin (increased sulfamethoxazole levels)

• Skin rash (including severe blistering or peeling)
• Fever
• Sore throat
• Unusual bleeding or bruising
• Yellowing of skin or eyes (jaundice)
• Dark urine
• Pale stools
• Severe diarrhea (especially if bloody or watery)
• Signs of hyperkalemia (muscle weakness, fatigue, paresthesias, bradycardia)
• Signs of hypoglycemia (sweating, tremor, confusion, dizziness)

Category D. Should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Avoid in the first trimester due to potential teratogenic effects (folate antagonism) and in the third trimester due to risk of kernicterus in the newborn.

Both sulfamethoxazole and trimethoprim are excreted into breast milk. Generally considered compatible with breastfeeding in healthy, full-term infants, but caution is advised. Avoid in infants with G6PD deficiency, hyperbilirubinemia, or those who are ill/premature.

Contraindicated in infants less than 2 months of age due to the risk of kernicterus. Use with caution in children with G6PD deficiency. Dosing is weight-based for children older than 2 months.

Increased risk of severe adverse reactions, including bone marrow suppression (especially thrombocytopenia with purpura when co-administered with thiazide diuretics), hyperkalemia, and renal impairment. Close monitoring of CBC, renal function, and serum potassium is essential. Lower doses or less frequent dosing may be required.

• This combination is often referred to as 'Bactrim' or 'Septra' (brand names) or 'SMX/TMP'.
• It is a common cause of drug-induced hyperkalemia, especially in patients with renal impairment, diabetes, or those on ACE inhibitors/ARBs/potassium-sparing diuretics.
• Patients should be well-hydrated to prevent crystalluria.
• Photosensitivity is a common side effect; advise patients to use sun protection.
• Discontinue at the first sign of rash due to the risk of severe cutaneous adverse reactions (SJS/TEN).
• Monitor for signs of myelosuppression (fever, sore throat, easy bruising/bleeding) during prolonged therapy.
• Trimethoprim can cause a false elevation in serum creatinine by interfering with some laboratory assays, without necessarily indicating true renal dysfunction. However, it can also cause true renal impairment, so clinical correlation is important.

• Fluoroquinolones (e.g., Ciprofloxacin, Levofloxacin) for UTIs, respiratory infections
• Beta-lactam antibiotics (e.g., Amoxicillin, Cephalexin) for UTIs, respiratory infections
• Tetracyclines (e.g., Doxycycline) for skin/soft tissue infections, respiratory infections
• Macrolides (e.g., Azithromycin) for respiratory infections
• Clindamycin or Pentamidine for PCP treatment/prophylaxis (if SMX/TMP is contraindicated or not tolerated)

If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it occurred.