Soma-DS
Generic Name
Sulfamethoxazole and Trimethoprim (Co-trimoxazole) 800 mg/160 mg Tablet
Manufacturer
Various manufacturers
Country
Global
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Price Details
Current market pricing information
| Variant | Unit Price | Strip Price |
|---|---|---|
| soma ds 800 mg tablet | ৳ 2.03 | ৳ 20.30 |
Description
Overview of the medicine
Soma-DS 800 mg tablet is a combination antibiotic containing sulfamethoxazole and trimethoprim. It is used to treat a wide range of bacterial infections, including urinary tract infections, respiratory tract infections, and certain gastrointestinal infections. The 'DS' denotes Double Strength, indicating higher doses of the active ingredients.
Uses & Indications
Dosage
Adults
One Soma-DS (800 mg sulfamethoxazole/160 mg trimethoprim) tablet every 12 hours for 10-14 days, depending on the infection.
Elderly
Similar to adult dosage, but caution with renal impairment; dosage adjustment may be needed based on creatinine clearance.
Renal_impairment
Adjust dosage based on creatinine clearance (CrCl): CrCl > 30 mL/min: normal dose; CrCl 15-30 mL/min: half normal dose; CrCl < 15 mL/min: not recommended or significantly reduced and monitored.
How to Take
Take orally with a full glass of water, with or without food. Ensure adequate fluid intake to prevent crystalluria.
Mechanism of Action
Sulfamethoxazole inhibits bacterial dihydrofolate synthesis by competing with para-aminobenzoic acid (PABA). Trimethoprim inhibits bacterial dihydrofolate reductase, blocking the synthesis of tetrahydrofolic acid. Together, they block sequential steps in bacterial folic acid metabolism, leading to synergistic antibacterial activity.
Pharmacokinetics
Onset
Antibacterial effects typically begin within 1-2 hours after administration.
Excretion
Mainly renal excretion of both unchanged drug and metabolites.
Half life
Sulfamethoxazole: 9-11 hours; Trimethoprim: 8-10 hours.
Absorption
Well absorbed orally, with peak plasma concentrations reached within 1-4 hours for sulfamethoxazole and 1-2 hours for trimethoprim.
Metabolism
Primarily hepatic metabolism for both drugs, via acetylation and glucuronidation for sulfamethoxazole, and oxidation for trimethoprim.
Side Effects
Contraindications
- Known hypersensitivity to sulfamethoxazole, trimethoprim, or any excipients
- Megaloblastic anemia due to folate deficiency
- Severe renal impairment (CrCl < 15 mL/min) without hemodialysis
- Severe hepatic impairment
- Infants less than 2 months of age
- Pregnancy (especially near term) and lactation (due to risk of kernicterus in neonates)
Drug Interactions
Warfarin
Increased anticoagulant effect, leading to increased risk of bleeding. Monitor INR closely.
Phenytoin
Increased phenytoin levels due to inhibition of metabolism.
Cyclosporine
Increased risk of nephrotoxicity.
Methotrexate
Increased methotrexate toxicity due to inhibition of renal tubular secretion and displacement from protein binding sites.
ACE Inhibitors/ARBs
Increased risk of hyperkalemia.
Diuretics (especially thiazides)
Increased risk of thrombocytopenia, particularly in elderly patients.
Storage
Store below 30°C in a dry place, away from light and moisture. Keep out of reach of children.
Overdose
Symptoms include nausea, vomiting, dizziness, headache, mental depression, and bone marrow depression. Treatment is symptomatic and supportive. Gastric lavage, emesis, and forced diuresis may be considered. Folinic acid may be given to counteract trimethoprim's effect on folate metabolism.
Pregnancy & Lactation
Pregnancy Category D. Should be avoided during pregnancy, especially near term, due to the risk of kernicterus in the neonate. Excreted in breast milk; generally not recommended during lactation due to potential risks to the infant (e.g., kernicterus, hemolytic anemia).
Side Effects
Contraindications
- Known hypersensitivity to sulfamethoxazole, trimethoprim, or any excipients
- Megaloblastic anemia due to folate deficiency
- Severe renal impairment (CrCl < 15 mL/min) without hemodialysis
- Severe hepatic impairment
- Infants less than 2 months of age
- Pregnancy (especially near term) and lactation (due to risk of kernicterus in neonates)
Drug Interactions
Warfarin
Increased anticoagulant effect, leading to increased risk of bleeding. Monitor INR closely.
Phenytoin
Increased phenytoin levels due to inhibition of metabolism.
Cyclosporine
Increased risk of nephrotoxicity.
Methotrexate
Increased methotrexate toxicity due to inhibition of renal tubular secretion and displacement from protein binding sites.
ACE Inhibitors/ARBs
Increased risk of hyperkalemia.
Diuretics (especially thiazides)
Increased risk of thrombocytopenia, particularly in elderly patients.
Storage
Store below 30°C in a dry place, away from light and moisture. Keep out of reach of children.
Overdose
Symptoms include nausea, vomiting, dizziness, headache, mental depression, and bone marrow depression. Treatment is symptomatic and supportive. Gastric lavage, emesis, and forced diuresis may be considered. Folinic acid may be given to counteract trimethoprim's effect on folate metabolism.
Pregnancy & Lactation
Pregnancy Category D. Should be avoided during pregnancy, especially near term, due to the risk of kernicterus in the neonate. Excreted in breast milk; generally not recommended during lactation due to potential risks to the infant (e.g., kernicterus, hemolytic anemia).
Frequently Asked Questions
Common questions about this medicine
Pack Sizes
Shelf Life
2-3 years from manufacturing date, check product specific expiry date.
Availability
Pharmacies, hospitals, clinics
Approval Status
Approved by major regulatory bodies (e.g., FDA, DGDA)
Patent Status
Off-patent
WHO Essential Medicine
YesClinical Trials
Extensive clinical trials since its introduction have established its efficacy and safety profile for various bacterial infections. Ongoing research explores its role in emerging antimicrobial resistance patterns.
Lab Monitoring
- Complete Blood Count (CBC) with differential (especially during prolonged therapy or in at-risk patients)
- Renal function tests (BUN, creatinine)
- Liver function tests (ALT, AST)
- Serum potassium levels (due to risk of hyperkalemia)
Doctor Notes
- Monitor CBC, renal function, and potassium levels in patients on prolonged therapy or those at risk.
- Advise patients to maintain adequate hydration to prevent crystalluria.
- Caution in patients with G6PD deficiency due to risk of hemolysis.
Patient Guidelines
- Complete the full course of treatment, even if symptoms improve.
- Drink plenty of fluids to prevent kidney stones.
- Avoid excessive sun exposure and use sunscreen due to photosensitivity.
- Report any severe skin rash or persistent diarrhea to your doctor immediately.
Missed Dose Advice
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and resume your regular dosing schedule. Do not double the dose.
Driving Precautions
May cause dizziness or fatigue. Exercise caution when driving or operating machinery until you know how the medicine affects you.
Lifestyle Advice
- Maintain good hygiene to prevent reinfection.
- Follow a balanced diet and stay hydrated.
- Avoid alcohol consumption during treatment.
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Global Brand Names
International brand names for this medicine. Click a brand to search for detailed information.