Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
BACTRIM DS vs ACTIQ
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
BACTRIM DS is a combination of sulfamethoxazole and trimethoprim. Sulfamethoxazole inhibits bacterial synthesis of dihydrofolic acid by competing with para-aminobenzoic acid (PABA), while trimethoprim inhibits dihydrofolate reductase, blocking reduction of dihydrofolate to tetrahydrofolate. This sequential blockade of folic acid synthesis leads to bactericidal action.
Opioid agonist; binds to mu-opioid receptors in the CNS, altering pain perception and response.
FDA-approved: Urinary tract infections, acute otitis media, acute exacerbations of chronic bronchitis, traveler's diarrhea, shigellosis, Pneumocystis jirovecii pneumonia (PCP), toxoplasmosis,Off-label: Methicillin-resistant Staphylococcus aureus (MRSA) infections, Stenotrophomonas maltophilia infections, nocardiosis, Wegener's granulomatosis (as second-line therapy), inflammatory bowel disease
Management of breakthrough pain in cancer patients aged 16 and older who are already receiving and tolerant to opioid therapy for their underlying persistent cancer pain
One double-strength tablet (trimethoprim 160 mg-sulfamethoxazole 800 mg) orally every 12 hours.
200 mcg transmucosally, titrated upward as needed; initial dose for opioid-tolerant patients is 200 mcg, with additional doses possible after 15 minutes if needed. Maximum 4 doses per episode. At least 4 hours between episodes.
Sulfamethoxazole: 8-10 hours; Trimethoprim: 8-12 hours; prolonged in renal impairment (creatinine clearance <30 m L/min: up to 24-48 hours).
Terminal half-life 0.83–2 hours (mean 1.3 h) in adults; note that context: transmucosal absorption leads to rapid onset but short duration; half-life is not correlated with clinical effect due to oral transmucosal route and rapid redistribution.
Sulfamethoxazole is metabolized primarily by N-acetylation and glucuronidation; trimethoprim is metabolized by O-demethylation and N-oxidation. Both are eliminated renally via glomerular filtration and tubular secretion.
Primarily hepatic via CYP3A4 to inactive metabolites (norfentanyl, despropionylfentanyl, hydroxyfentanyl) and other metabolites; <7% excreted unchanged in urine.
Renal: 50-70% as sulfamethoxazole (unchanged and acetylated metabolite), 40-60% as trimethoprim (unchanged); biliary: <10% for both; fecal: <4%.
Primarily renal as metabolites (about 75% as metabolites, <10% unchanged). Fecal excretion accounts for <9%. Biliary excretion is minor.
Sulfamethoxazole: 68% bound (albumin); Trimethoprim: 44% bound (albumin, alpha-1-acid glycoprotein).
Fentanyl is 80–85% bound to plasma proteins (primarily albumin and α1-acid glycoprotein).
Sulfamethoxazole: 0.21 L/kg; Trimethoprim: 1.3-1.8 L/kg (wide distribution, higher in tissues than plasma).
Approximately 4 L/kg (range 3–6 L/kg); large Vd indicates extensive tissue distribution and redistribution contributing to short duration.
Oral: >90% for both components; IV: 100%.
Oral transmucosal: 50% (range 47–54%) relative to IV; variable and enhanced by rapid absorption through buccal mucosa.
Cr Cl >30 m L/min: No adjustment; Cr Cl 15-30 m L/min: 50% of usual dose every 12 hours; Cr Cl <15 m L/min: Not recommended.
No specific GFR-based dose adjustment recommended; use with caution in severe renal impairment (Cr Cl < 30 m L/min) and consider dose reduction due to potential accumulation.
Child-Pugh Class A: No adjustment; Child-Pugh Class B: Use with caution, no specific dose recommendation; Child-Pugh Class C: Contraindicated.
Child-Pugh Class A/B: No adjustment. Child-Pugh Class C: Reduce initial dose to 100 mcg and titrate slowly; monitor closely for prolonged effects.
Based on trimethoprim component: 8 mg/kg/day of trimethoprim divided every 12 hours. For severe infections, up to 20 mg/kg/day of trimethoprim divided every 6 hours.
Not approved for pediatric use; safety and efficacy not established in patients under 16 years.
Monitor renal function; adjust dose based on Cr Cl. Increased risk of hyperkalemia and folate deficiency; consider folate supplementation.
Initiate at 100 mcg transmucosally; titrate slowly due to increased sensitivity and risk of respiratory depression. Monitor for adverse effects.
BACTRIM DS carries a black box warning for severe hypersensitivity reactions including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and fulminant hepatic necrosis. Also warns about fatal reactions such as agranulocytosis, aplastic anemia, and other blood dyscrasias. Additionally, use in pregnancy at term may cause kernicterus in the newborn.
Risk of respiratory depression, addiction, abuse, and misuse; accidental ingestion can be fatal; concomitant use with benzodiazepines or CNS depressants may cause profound sedation, respiratory depression, coma, and death; not for use in opioid non-tolerant patients; risk of neonatal opioid withdrawal syndrome with prolonged use during pregnancy; serious, life-threatening, or fatal respiratory depression may occur even at recommended doses.
Hypersensitivity reactions: risk of SJS/TEN, especially in patients with HIV, folate deficiency, or genetic susceptibility (e.g., HLA-B*1502, HLA-A*3101). Discontinue at first sign of rash.,Hematologic toxicity: monitor CBCs; caution in patients with folate deficiency, renal impairment, or prolonged therapy.,Hepatic toxicity: can cause cholestatic jaundice, hepatic necrosis; avoid in hepatic impairment.,Renal toxicity: maintain adequate hydration to prevent crystalluria; adjust dose in renal impairment.,Hyperkalemia: risk with high-dose trimethoprim; monitor potassium, especially in patients with renal dysfunction or on potassium-sparing diuretics.,Hypoglycemia: risk in patients with renal impairment or malnutrition; caution with sulfonylureas.,Photosensitivity: avoid excessive sun exposure.,Pregnancy: avoid at term due to risk of kernicterus; use only if benefit outweighs risk.,Lactation: caution due to potential for kernicterus in infants with G6PD deficiency.
Risk of respiratory depression; addiction, abuse, and misuse; interactions with CNS depressants; serotonin syndrome; adrenal insufficiency; severe hypotension; seizures; withdrawal; use in patients with head injuries, increased intracranial pressure, biliary tract disease, pancreatitis; risk of choking with lozenge; oral mucosal irritation; dental caries; hypokalemia; hyponatremia; use in elderly, cachectic, or debilitated patients.
Hypersensitivity to sulfamethoxazole, trimethoprim, or any component.,History of drug-induced immune thrombocytopenia with sulfonamides or trimethoprim.,Severe hepatic disease (e.g., acute hepatitis, cirrhosis with jaundice).,Severe renal impairment (Cr Cl <15 m L/min) unless dialysis is available.,Megaloblastic anemia due to folate deficiency.,Pregnancy at term and nursing mothers (due to risk of kernicterus).,Concurrent use with dofetilide (increased risk of arrhythmias).,Infants <2 months of age (sulfonamides can cause kernicterus).
Significant respiratory depression; acute or severe bronchial asthma in an unmonitored setting or without resuscitative equipment; known or suspected paralytic ileus; hypersensitivity to fentanyl or any component; opioid non-tolerant patients; management of acute or postoperative pain including headache/migraine, dental pain, or emergency department use.
Avoid high-potassium foods (e.g., bananas, oranges, potatoes) as trimethoprim can increase serum potassium. Avoid alcohol, which may cause disulfiram-like reaction (flushing, nausea, tachycardia). No significant food-drug interactions beyond potassium and alcohol.
No significant food interactions. Grapefruit juice may increase fentanyl levels, but specific studies with ACTIQ are lacking. Avoid alcohol, as it may increase sedation and respiratory depression risk.
First trimester: Folate antagonist; associated with neural tube defects, cardiovascular malformations, and cleft palate. Second trimester: Growth restriction, preterm birth. Third trimester: Kernicterus risk due to bilirubin displacement from albumin. Avoid during entire pregnancy.
FDA Pregnancy Category C. First trimester: limited human data; animal studies show increased resorptions and fetal growth restriction. Second/third trimester: chronic use may cause neonatal opioid withdrawal syndrome; avoid use during labor due to risk of neonatal respiratory depression.
Breastfeeding safety: Both trimethoprim and sulfamethoxazole are excreted into breast milk; M/P ratio for trimethoprim ~1.25, sulfamethoxazole ~0.15. Caution in infants under 2 months or with G6PD deficiency; theoretical risk of kernicterus.
Excreted in breast milk; M/P ratio not established. Limited data suggest low levels, but risk of infant sedation and respiratory depression. Avoid use while breastfeeding unless potential benefit outweighs risk.
No standard dose adjustment recommended; avoid use if possible. If necessary, ensure adequate folic acid intake; may need to increase dose due to increased clearance in pregnancy, but specific data lacking.
Due to increased plasma volume and hepatic metabolism in pregnancy, dose requirements may increase; adjust based on clinical response and tolerance. Avoid use during labor and delivery due to risk of neonatal respiratory depression; short-term use preferred.
Bactrim DS (sulfamethoxazole/trimethoprim) is contraindicated in G6PD deficiency due to risk of hemolytic anemia. Monitor for hyperkalemia, especially in elderly or those with renal impairment. Caution with warfarin (potentiates anticoagulation). Avoid in pregnancy (teratogenic) and lactation. Use with caution in folate deficiency; supplement folate if needed.
ACTIQ is a transmucosal immediate-release fentanyl formulation indicated for breakthrough cancer pain in opioid-tolerant patients. Initiate with the lowest strength (200 mcg) and titrate upward. Avoid use in opioid-naive patients due to risk of fatal respiratory depression. Place the unit between cheek and lower gum, not sublingually. Instruct patient not to bite or suck the unit. Monitor for sedation and respiratory depression. Multiple units may be used per episode if needed, but wait at least 4 hours before next episode. Dispose of partially used units by flushing down toilet.
Take with a full glass of water and stay well-hydrated to prevent crystalluria.,Avoid prolonged sun exposure; use sunscreen as this drug may cause photosensitivity.,Complete the full course even if you feel better to prevent antibiotic resistance.,Report any skin rash, sore throat, fever, or unusual bleeding immediately.,Do not take if you are pregnant, planning to become pregnant, or breastfeeding.,Inform your doctor if you have kidney disease, G6PD deficiency, or are on blood thinners.
Only use ACTIQ if you are already taking regular around-the-clock opioid pain medicine and are tolerant to opioids.,Do not use ACTIQ for short-term pain like after surgery, headache, or dental pain.,Place the unit in your cheek pouch, not under your tongue. Do not chew or suck it.,If you need more than 4 units per day, contact your doctor as your dose may need adjustment.,Store ACTIQ in a safe place away from children, as accidental ingestion can be fatal.,Dispose of unused or partially used units by flushing them down the toilet.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about BACTRIM DS vs ACTIQ, answered by our medical review team.
BACTRIM DS is a Sulfonamide Antibiotic Combination that works by BACTRIM DS is a combination of sulfamethoxazole and trimethoprim. Sulfamethoxazole inhibits bacterial synthesis of dihydrofolic acid by competing with para-aminobenzoic acid (PABA), while trimethoprim inhibits dihydrofolate reductase, blocking reduction of dihydrofolate to tetrahydrofolate. This sequential blockade of folic acid synthesis leads to bactericidal action.. ACTIQ is a Opioid Analgesic that works by Opioid agonist; binds to mu-opioid receptors in the CNS, altering pain perception and response.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between BACTRIM DS and ACTIQ depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of BACTRIM DS is: One double-strength tablet (trimethoprim 160 mg-sulfamethoxazole 800 mg) orally every 12 hours.. The standard adult dose of ACTIQ is: 200 mcg transmucosally, titrated upward as needed; initial dose for opioid-tolerant patients is 200 mcg, with additional doses possible after 15 minutes if needed. Maximum 4 doses per episode. At least 4 hours between episodes.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between BACTRIM DS and ACTIQ in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. BACTRIM DS is classified as Category C. First trimester: Folate antagonist; associated with neural tube defects, cardiovascular malformations, and cleft palate. Second trimester: Growth restriction, preterm birth. Third . ACTIQ is classified as Category C. FDA Pregnancy Category C. First trimester: limited human data; animal studies show increased resorptions and fetal growth restriction. Second/third trimester: chronic use may cause. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.