Bactrim 200-40mg/5ml Pediatric Susp
It is used to treat or prevent bacterial infections.
Drug Class
Antibiotic
Pharmacologic Class
Folic acid synthesis inhibitor (sulfonamide and dihydrofolate reductase inhibitor combination)
Pregnancy Category
Category D
FDA Approved
Aug 1973
DEA Schedule
Not Controlled
Overview
What is this medicine?
This medicine is a combination of two antibiotics that work together to stop the growth of bacteria. It's used to treat various bacterial infections, like urinary tract infections, ear infections, and certain types of pneumonia.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your medication and follow the instructions closely. You can take this medication with or without food, but if it causes stomach upset, take it with food. Always take it with a full glass of water. To establish a routine, take your medication at the same time every day.
Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel well. It's essential to drink plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake.
Before taking your medication, shake the bottle well if you're using a liquid form. Measure the liquid dose carefully using the measuring device provided with the medication. If no device is included, ask your pharmacist for a suitable measuring tool.
Storing and Disposing of Your Medication
Store your medication at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep all medications in a safe location, out of the reach of children and pets.
When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so by your doctor or pharmacist. Instead, check with your pharmacist for guidance on the best disposal method. You may also want to explore local drug take-back programs.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your medication and follow the instructions closely. You can take this medication with or without food, but if it causes stomach upset, take it with food. Always take it with a full glass of water. To establish a routine, take your medication at the same time every day.
Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel well. It's essential to drink plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake.
Before taking your medication, shake the bottle well if you're using a liquid form. Measure the liquid dose carefully using the measuring device provided with the medication. If no device is included, ask your pharmacist for a suitable measuring tool.
Storing and Disposing of Your Medication
Store your medication at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep all medications in a safe location, out of the reach of children and pets.
When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless instructed to do so by your doctor or pharmacist. Instead, check with your pharmacist for guidance on the best disposal method. You may also want to explore local drug take-back programs.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Drink plenty of fluids (6-8 glasses of water daily) to prevent kidney stones and help the medicine work.
- Avoid prolonged sun exposure and use sunscreen, as this medication can make your skin more sensitive to the sun.
- Take the medicine exactly as prescribed, even if you start feeling better. Do not skip doses or stop early.
- Shake the suspension well before each use.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Standard Dose:
Standard dosing varies by indication. For uncomplicated UTI: 160 mg TMP / 800 mg SMX every 12 hours for 3-7 days.
Condition-Specific Dosing:
uncomplicated_UTI:
160 mg TMP / 800 mg SMX every 12 hours for 3-7 days
PCP_prophylaxis:
80 mg TMP / 400 mg SMX once daily or 3 times per week
PCP_treatment:
15-20 mg TMP / kg/day (based on TMP) divided every 6-8 hours for 14-21 days
Pediatric Dosing
Neonatal:
Not established (contraindicated in infants < 2 months due to kernicterus risk)
Infant:
Not established (contraindicated in infants < 2 months). For infants > 2 months, dosing is weight-based.
Child:
Based on Trimethoprim component: 8-10 mg TMP/kg/day (for infections like otitis media, UTI) divided every 12 hours. For PCP treatment: 15-20 mg TMP/kg/day divided every 6-8 hours. Max dose: 320 mg TMP / 1600 mg SMX per day.
Adolescent:
Dosing similar to adult dosing, or weight-based if lower weight, typically 8-10 mg TMP/kg/day divided every 12 hours for common infections.
Dose Adjustments
Renal Impairment:
Mild:
CrCl 30-50 mL/min: Reduce dose by 50% or administer standard dose every 12-18 hours.
Moderate:
CrCl 15-30 mL/min: Reduce dose by 50% or administer standard dose every 24 hours.
Severe:
CrCl < 15 mL/min: Not recommended unless plasma concentrations can be monitored. If used, reduce dose by 75% or administer standard dose every 48 hours.
Dialysis:
Hemodialysis: Administer 50% of the usual dose after each dialysis session. Peritoneal Dialysis: Not well studied, generally not recommended or requires significant dose reduction.
Hepatic Impairment:
Mild:
No specific adjustment recommended.
Moderate:
Use with caution; monitor for signs of toxicity. Dose adjustment may be necessary.
Severe:
Use with extreme caution or avoid; significant hepatic impairment can lead to accumulation and increased toxicity. Contraindicated in severe hepatic damage.
Pharmacology
Mechanism of Action
Sulfamethoxazole (SMX) inhibits bacterial dihydrofolic acid synthesis by competing with para-aminobenzoic acid (PABA). Trimethoprim (TMP) inhibits dihydrofolate reductase, blocking the production of tetrahydrofolic acid. This sequential blockade of two enzymes in the bacterial folic acid synthesis pathway results in a synergistic bactericidal effect.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 90-100% (oral)
Tmax:
SMX: 3-4 hours; TMP: 1-4 hours
FoodEffect:
Absorption is not significantly affected by food, but may be slightly delayed.
Distribution:
Vd:
SMX: 0.16-0.35 L/kg; TMP: 1.3-1.8 L/kg (TMP has a larger volume of distribution, indicating good tissue penetration)
ProteinBinding:
SMX: 66%; TMP: 44%
CnssPenetration:
Yes (good penetration into CSF, especially when meninges are inflamed)
Elimination:
HalfLife:
SMX: 9-11 hours; TMP: 8-10 hours
Clearance:
Primarily renal clearance for both components.
ExcretionRoute:
Renal (glomerular filtration and tubular secretion)
Unchanged:
SMX: 20% (unchanged); TMP: 50-60% (unchanged)
Pharmacodynamics
OnsetOfAction:
Rapid (within 1-2 hours for antibacterial effect)
PeakEffect:
Within 2-4 hours after oral administration
DurationOfAction:
Approximately 12 hours (allows for twice-daily dosing)
Confidence:
High
Safety & Warnings
BLACK BOX WARNING
FATALITIES ASSOCIATED WITH THE ADMINISTRATION OF SULFONAMIDES, ALTHOUGH RARE, HAVE OCCURRED DUE TO SEVERE REACTIONS INCLUDING STEVENS-JOHNSON SYNDROME, TOXIC EPIDERMAL NECROLYSIS, FULMINANT HEPATIC NECROSIS, AGRANULOCYTOSIS, APLASTIC ANEMIA, AND OTHER BLOOD DYSCRASIAS. SULFONAMIDES SHOULD BE DISCONTINUED AT THE FIRST APPEARANCE OF SKIN RASH OR ANY SIGN OF ADVERSE REACTION. CLINICAL SIGNS SUCH AS SORE THROAT, FEVER, PALLOR, PURPURA, OR JAUNDICE MAY BE EARLY INDICATIONS OF SERIOUS REACTIONS. COUGH, SHORTNESS OF BREATH, AND PULMONARY INFILTRATES ARE ALSO REPORTED AS SIGNS OF HYPERSENSITIVITY REACTIONS.
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an 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.
Signs of high potassium levels: abnormal heartbeat, confusion, weakness, lightheadedness, dizziness, numbness or tingling, or shortness of breath.
Signs of low blood sugar: dizziness, headache, sleepiness, weakness, shaking, rapid heartbeat, confusion, hunger, or sweating.
Signs of kidney problems: inability to urinate, changes in urine output, blood in the urine, or significant weight gain.
Signs of low sodium levels: headache, difficulty focusing, memory problems, confusion, weakness, seizures, or balance changes.
Signs of lung or breathing problems: shortness of breath, trouble breathing, cough, or fever.
Signs of pancreatitis: severe stomach pain, severe back pain, or severe nausea and vomiting.
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 and 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, contact your doctor immediately. Before treating diarrhea, consult with your doctor.
Rare but Serious Side Effects
Sulfa drugs, like this medication, can cause rare but severe side effects, including liver problems, blood disorders, and severe skin reactions (Stevens-Johnson syndrome/toxic epidermal necrolysis). If you notice 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
Feeling extremely tired or weak
Bruising or bleeding
Signs of liver problems: dark urine, fatigue, decreased appetite, nausea, stomach pain, light-colored stools, vomiting, or yellow skin and eyes.
Other Serious Side Effects
This medication may increase the risk of aseptic meningitis, a severe brain problem. If you experience any of the following symptoms, contact your doctor immediately:
Headache, fever, chills, severe nausea, vomiting, stiff neck, rash, sensitivity to light, sleepiness, or confusion.
Additionally, this medication can cause hemophagocytic lymphohistiocytosis (HLH), a life-threatening immune system problem. If you notice any of the following symptoms, seek medical attention right away:
Fever, swollen glands, rash, seizures, confusion, balance changes, or difficulty walking.
Common Side Effects
Most people do not experience severe side effects, but some may have mild or moderate side effects. If you notice any of the following symptoms, contact your doctor if they bother you or do not go away:
Diarrhea, stomach pain, nausea, vomiting, or decreased appetite.
Reporting Side Effects
If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an 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.
Signs of high potassium levels: abnormal heartbeat, confusion, weakness, lightheadedness, dizziness, numbness or tingling, or shortness of breath.
Signs of low blood sugar: dizziness, headache, sleepiness, weakness, shaking, rapid heartbeat, confusion, hunger, or sweating.
Signs of kidney problems: inability to urinate, changes in urine output, blood in the urine, or significant weight gain.
Signs of low sodium levels: headache, difficulty focusing, memory problems, confusion, weakness, seizures, or balance changes.
Signs of lung or breathing problems: shortness of breath, trouble breathing, cough, or fever.
Signs of pancreatitis: severe stomach pain, severe back pain, or severe nausea and vomiting.
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 and 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, contact your doctor immediately. Before treating diarrhea, consult with your doctor.
Rare but Serious Side Effects
Sulfa drugs, like this medication, can cause rare but severe side effects, including liver problems, blood disorders, and severe skin reactions (Stevens-Johnson syndrome/toxic epidermal necrolysis). If you notice 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
Feeling extremely tired or weak
Bruising or bleeding
Signs of liver problems: dark urine, fatigue, decreased appetite, nausea, stomach pain, light-colored stools, vomiting, or yellow skin and eyes.
Other Serious Side Effects
This medication may increase the risk of aseptic meningitis, a severe brain problem. If you experience any of the following symptoms, contact your doctor immediately:
Headache, fever, chills, severe nausea, vomiting, stiff neck, rash, sensitivity to light, sleepiness, or confusion.
Additionally, this medication can cause hemophagocytic lymphohistiocytosis (HLH), a life-threatening immune system problem. If you notice any of the following symptoms, seek medical attention right away:
Fever, swollen glands, rash, seizures, confusion, balance changes, or difficulty walking.
Common Side Effects
Most people do not experience severe side effects, but some may have mild or moderate side effects. If you notice any of the following symptoms, contact your doctor if they bother you or do not go away:
Diarrhea, stomach pain, nausea, vomiting, or decreased appetite.
Reporting Side Effects
If you have questions or concerns about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- New or worsening skin rash, blistering, peeling skin, or sores in the mouth/eyes (seek immediate medical attention)
- Sore throat, fever, chills, unusual tiredness, or easy bruising/bleeding (signs of blood problems)
- Yellowing of the skin or eyes (jaundice), dark urine, severe stomach pain (signs of liver problems)
- Severe diarrhea that is watery or bloody (may be a sign of C. difficile infection)
- Swelling of the face, lips, tongue, or throat; difficulty breathing (allergic reaction)
- Muscle weakness, irregular heartbeat (signs of high potassium)
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following conditions or situations before starting this medication:
Any allergies you have, including allergies to this drug, its components, or other substances, such as foods or medications. Describe the allergic reaction you experienced, including any 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 use of antiseizure medications.
A history of low platelet count when taking trimethoprim or sulfa (sulfonamide) drugs.
Current or recent use of the following medications:
+ Amantadine
+ Cyclosporine
+ Dofetilide
+ Indomethacin
+ Leucovorin
+ Methotrexate
+ Pyrimethamine
+ Angiotensin-converting enzyme (ACE) inhibitors, such as:
- 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. It is not recommended for infants younger than 2 months old.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine the safety of taking this medication with your existing health conditions and medications. Never start, stop, or change the dose of any medication without consulting your doctor.
It is essential to inform your doctor about the following conditions or situations before starting this medication:
Any allergies you have, including allergies to this drug, its components, or other substances, such as foods or medications. Describe the allergic reaction you experienced, including any 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 use of antiseizure medications.
A history of low platelet count when taking trimethoprim or sulfa (sulfonamide) drugs.
Current or recent use of the following medications:
+ Amantadine
+ Cyclosporine
+ Dofetilide
+ Indomethacin
+ Leucovorin
+ Methotrexate
+ Pyrimethamine
+ Angiotensin-converting enzyme (ACE) inhibitors, such as:
- 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. It is not recommended for infants younger than 2 months old.
This list is not exhaustive, and it is crucial to discuss all your medications, including prescription and over-the-counter drugs, natural products, and vitamins, with your doctor and pharmacist. They will help you determine the safety of taking this medication with your existing health conditions and medications. Never start, stop, or change the dose of any medication without consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Regular blood work and laboratory tests, as directed by your doctor, are crucial to monitor your condition. Be aware that this medication may interfere with certain lab tests, so it is vital to notify all your healthcare providers and laboratory personnel that you are taking this drug.
Do not exceed the recommended duration of treatment, 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 more susceptible to anemia. This deficiency is more common in individuals of African, South Asian, Middle Eastern, and Mediterranean descent.
If you have diabetes, it is crucial to closely monitor your blood sugar levels. Additionally, consult your doctor before consuming alcohol. This medication may increase your sensitivity to the sun, making you more prone to sunburn. Take necessary precautions when exposed to sunlight, and inform your doctor if you experience excessive sunburn.
A severe and potentially life-threatening reaction may occur, characterized by symptoms such as fever, rash, or swollen glands, accompanied by problems in organs like 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 your doctor to discuss potential risks to your baby.
Do not exceed the recommended duration of treatment, 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 more susceptible to anemia. This deficiency is more common in individuals of African, South Asian, Middle Eastern, and Mediterranean descent.
If you have diabetes, it is crucial to closely monitor your blood sugar levels. Additionally, consult your doctor before consuming alcohol. This medication may increase your sensitivity to the sun, making you more prone to sunburn. Take necessary precautions when exposed to sunlight, and inform your doctor if you experience excessive sunburn.
A severe and potentially life-threatening reaction may occur, characterized by symptoms such as fever, rash, or swollen glands, accompanied by problems in organs like 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 your doctor to discuss potential risks to your baby.
Overdose Information
Overdose Symptoms:
- Nausea, vomiting, diarrhea
- Dizziness, headache
- Confusion, mental depression
- Bone marrow depression (e.g., low white blood cell count, low platelet count)
- Fever
- Jaundice
- Crystalluria, hematuria, anuria
What to Do:
Call 1-800-222-1222 (Poison Control). Seek immediate medical attention. Treatment is supportive and may include gastric lavage, forced diuresis, and alkalinization of urine to increase SMX excretion. Leucovorin may be administered to counteract TMP's folate antagonist effects.
Drug Interactions
Contraindicated Interactions
- Dofetilide (increased dofetilide concentrations, risk of QT prolongation and Torsades de Pointes)
- Methotrexate (increased methotrexate levels, increased risk of bone marrow suppression)
Major Interactions
- Warfarin (potentiates anticoagulant effect, increased bleeding risk)
- Phenytoin (increased phenytoin levels, risk of toxicity)
- Digoxin (increased digoxin levels, especially in elderly)
- Potassium-sparing diuretics (e.g., spironolactone, amiloride) and ACE inhibitors/ARBs (increased risk of hyperkalemia)
- Cyclosporine (decreased cyclosporine levels, increased risk of nephrotoxicity)
- Lamivudine (increased lamivudine levels)
- Procainamide (increased procainamide levels)
- Rifampin (decreased TMP levels)
Moderate Interactions
- Oral hypoglycemics (sulfonylureas) (increased hypoglycemic effect)
- Thiazide diuretics (increased risk of thrombocytopenia with purpura in elderly)
- Tricyclic antidepressants (increased TCA levels)
- Amantadine (increased amantadine levels, risk of toxicity)
- Memantine (increased memantine levels)
- Pyrimethamine (increased risk of megaloblastic anemia)
- Zidovudine (increased zidovudine levels, increased risk of hematologic toxicity)
Minor Interactions
- Antacids (may decrease absorption, separate administration)
- Methenamine (increased risk of crystalluria)
Monitoring
Baseline Monitoring
Complete Blood Count (CBC) with differential
Rationale: To establish baseline hematologic status and monitor for potential bone marrow suppression (e.g., neutropenia, thrombocytopenia, megaloblastic anemia).
Timing: Prior to initiation of therapy, especially for prolonged courses or high doses.
Renal function (BUN, creatinine, eGFR)
Rationale: To assess baseline kidney function and guide dosing adjustments, as the drug is primarily renally eliminated.
Timing: Prior to initiation of therapy.
Liver function tests (ALT, AST, bilirubin)
Rationale: To assess baseline hepatic function and monitor for potential hepatotoxicity.
Timing: Prior to initiation of therapy, especially in patients with pre-existing liver disease.
Serum potassium
Rationale: To establish baseline potassium levels, as TMP can cause hyperkalemia, particularly in patients with renal impairment or those on other potassium-elevating drugs.
Timing: Prior to initiation of therapy.
Routine Monitoring
Complete Blood Count (CBC) with differential
Frequency: Weekly or every 2-3 days for high-dose or prolonged therapy (e.g., PCP treatment); less frequently for short courses.
Target: Within normal limits for age
Action Threshold: Discontinue if significant decrease in any cell line (e.g., neutrophil count < 1000/mm³, platelet count < 50,000/mm³).
Renal function (BUN, creatinine)
Frequency: Weekly for prolonged therapy or in patients with renal impairment/risk factors; as clinically indicated for short courses.
Target: Stable or improving
Action Threshold: Significant increase in creatinine or BUN may require dose adjustment or discontinuation.
Serum potassium
Frequency: Weekly for prolonged therapy, in patients with renal impairment, or those at risk for hyperkalemia.
Target: 3.5-5.0 mEq/L
Action Threshold: >5.5 mEq/L (consider dose reduction or discontinuation, manage hyperkalemia).
Liver function tests (ALT, AST)
Frequency: Periodically for prolonged therapy or if signs of hepatic dysfunction develop.
Target: Within normal limits
Action Threshold: Significant elevation (e.g., >3x ULN) may require discontinuation.
Symptom Monitoring
- Skin rash (e.g., Stevens-Johnson Syndrome, Toxic Epidermal Necrolysis)
- Sore throat, fever, pallor, easy bruising/bleeding (signs of bone marrow suppression)
- Jaundice, dark urine, abdominal pain (signs of hepatotoxicity)
- Severe diarrhea, abdominal cramps (Clostridioides difficile-associated diarrhea)
- Signs of hyperkalemia (e.g., muscle weakness, fatigue, palpitations)
- Signs of crystalluria (e.g., flank pain, hematuria, oliguria)
Special Patient Groups
Pregnancy
Category D. Should be avoided during pregnancy, especially in the first trimester due to folate antagonism (risk of neural tube defects) and in the third trimester due to kernicterus risk in the newborn (displaces bilirubin from albumin). Use only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Increased risk of neural tube defects and other congenital malformations due to folate antagonism.
Second Trimester:
Generally considered safer than first or third trimester, but still Category D. Use with caution.
Third Trimester:
Increased risk of kernicterus in the newborn, especially if administered near term, due to displacement of bilirubin from albumin.
Lactation
L3 (Moderately Safe). Both SMX and TMP are excreted into breast milk. Generally considered compatible with breastfeeding, but caution is advised, especially in infants with hyperbilirubinemia, G6PD deficiency, or those who are ill/premature, due to theoretical risk of kernicterus or hemolytic anemia. Monitor infant for rash, diarrhea, or jaundice.
Infant Risk:
Low to moderate risk. Potential for kernicterus in jaundiced or G6PD deficient infants; theoretical risk of hemolytic anemia in G6PD deficient infants. Monitor for adverse effects.
Pediatric Use
Contraindicated in infants less than 2 months of age due to the risk of kernicterus. Use with caution in children with G6PD deficiency due to risk of hemolytic anemia. Dosing is weight-based and must be carefully calculated.
Geriatric Use
Increased risk of severe adverse reactions, including bone marrow suppression, hyperkalemia, and severe skin reactions. Increased risk of thrombocytopenia with purpura when co-administered with thiazide diuretics. Renal function should be carefully monitored and dose adjusted accordingly.
Clinical Information
Clinical Pearls
- Always confirm patient's allergy status to sulfonamides before prescribing.
- Ensure adequate hydration to prevent crystalluria, especially in pediatric patients.
- Monitor potassium levels, particularly in patients with renal impairment, elderly, or those on ACE inhibitors/ARBs or potassium-sparing diuretics.
- Counsel patients on photosensitivity and the importance of sun protection.
- Be vigilant for signs of severe skin reactions (SJS/TEN) and advise patients to discontinue the drug immediately and seek medical attention if a rash develops.
- For pediatric dosing, always calculate based on the trimethoprim (TMP) component and the child's weight.
Alternative Therapies
- Amoxicillin/clavulanate (for otitis media, some UTIs)
- Cephalexin (for UTIs, skin infections)
- Nitrofurantoin (for uncomplicated UTIs)
- Fluoroquinolones (e.g., ciprofloxacin, levofloxacin - generally avoided in pediatrics unless no other option)
- Macrolides (e.g., azithromycin - for some respiratory infections)
- Doxycycline (for some respiratory, skin infections, traveler's diarrhea)
Cost & Coverage
Average Cost:
Varies widely per 100ml bottle
Generic Available:
Yes
Insurance Coverage:
Tier 1 or 2 (Generic)
General Drug Facts
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 this 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 medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it happened.