SEPTRIN™ (Co-trimoxazole)
1. Disclaimer
This information is provided for educational and reference purposes only and is not a substitute for diagnosis, prescribing, or individualized medical advice from a qualified healthcare professional. Septrin/co-trimoxazole should be used only for appropriate indications and according to the applicable product information, antimicrobial-susceptibility data, local treatment guidance, and the patient's clinical circumstances.
We do not guarantee the accuracy, currency or completeness of information regarding medications or medical products, and official sources should be verified before making any decisions. Readers are responsible for independently verifying the information before relying on it.
2. Summary
SEPTRIN™ is a brand of co-trimoxazole, an antibacterial combination containing trimethoprim and sulfamethoxazole in a fixed ratio. The two agents inhibit successive steps in microbial folate metabolism, producing synergistic antimicrobial activity.
Current UK product information supports co-trimoxazole for selected susceptible bacterial infections and for the treatment and prevention of Pneumocystis jirovecii pneumonitis/pneumonia (PJP/PCP), as well as treatment and prophylaxis of toxoplasmosis and treatment of nocardiosis. For selected bacterial infections, its use should be based on evidence of susceptibility and a good reason to prefer the combination over an effective single antibacterial agent.
SEPTRIN product information describes a standard adult strength of 80 mg trimethoprim + 400 mg sulfamethoxazole, a double-strength formulation containing 160 mg + 800 mg, and paediatric and suspension formulations.
For the Egyptian market, currently accessible drug-database and retail information identifies SEPTRIN D.S. 160 mg/800 mg tablets and SEPTRIN oral suspension containing 40 mg trimethoprim + 200 mg sulfamethoxazole per 5 mL. Availability, registration status, manufacturer details and marketed pack sizes may change and should be verified through the Egyptian Drug Authority or the current Egyptian product packaging.
3. Brand Name
SEPTRIN™
Common formulation-specific names include:
- SEPTRIN D.S. / Double Strength — 160 mg trimethoprim + 800 mg sulfamethoxazole per tablet.
- SEPTRIN Oral/Paediatric Suspension — 40 mg trimethoprim + 200 mg sulfamethoxazole per 5 mL in the Egyptian product currently identified in accessible databases.
SEPTRIN was historically a GlaxoSmithKline brand. Aspen subsequently acquired rights to Septrin among a group of specialist branded products for worldwide distribution, and current UK co-trimoxazole products cited in this review are marketed by Aspen. This international ownership and regulatory information should not, however, be assumed to establish the current Egyptian marketing-authorisation holder for every Egyptian SEPTRIN presentation.
4. Category
Therapeutic category: Antibacterial / Antibiotic
Pharmacological class: Sulfonamide and trimethoprim antibacterial combination
Active combination: Trimethoprim + sulfamethoxazole
ATC classification: J01EE01 — Sulfamethoxazole and trimethoprim
Co-trimoxazole is classified as a prescription-only antibacterial medicine in current UK product information.
5. Active Ingredient
Each active ingredient contributes to inhibition of microbial folate metabolism:
Trimethoprim
Trimethoprim reversibly inhibits dihydrofolate reductase (DHFR), reducing conversion of dihydrofolate to tetrahydrofolate.
Sulfamethoxazole
Sulfamethoxazole competitively inhibits utilization of para-aminobenzoic acid (PABA) in the synthesis of dihydrofolate.
By blocking two successive steps of the folate pathway, the combination produces marked potentiation of antimicrobial activity. Trimethoprim has far greater affinity for bacterial DHFR than for the corresponding mammalian enzyme.
6. Pharmaceutical Form & Strength
SEPTRIN product information has described several oral formulations:
| Form | Trimethoprim | Sulfamethoxazole |
|---|---|---|
| Adult tablet | 80 mg | 400 mg |
| Dispersible tablet | 80 mg | 400 mg |
| Double-strength (D.S./Forte) tablet | 160 mg | 800 mg |
| Paediatric tablet | 20 mg | 100 mg |
| Capsule | 80 mg | 400 mg |
| Adult oral suspension | 80 mg/5 mL | 400 mg/5 mL |
| Paediatric oral suspension | 40 mg/5 mL | 200 mg/5 mL |
These presentations should not be interpreted as all being currently marketed in every country.
For Egypt, currently accessible market databases specifically identify:
- SEPTRIN D.S. tablet: 800 mg sulfamethoxazole + 160 mg trimethoprim.
- SEPTRIN oral suspension: 200 mg sulfamethoxazole + 40 mg trimethoprim per 5 mL.
The 80 mg trimethoprim/400 mg sulfamethoxazole per 5 mL Adult Suspension discussed elsewhere in current UK product information is a different concentration and should not be confused with the Egyptian 40/200 mg per 5 mL suspension.
7. Manufacturer & Marketing Authorization Holder
SEPTRIN has a longstanding association with GlaxoSmithKline (GSK). Egyptian product databases currently identify Glaxo SmithKline Egypt as the laboratory/company associated with both SEPTRIN D.S. 800/160 mg tablets and SEPTRIN oral suspension 200/40 mg per 5 mL.
Separately, Aspen acquired worldwide distribution rights to Septrin among several specialist GSK brands in transactions completed in 2009. For the specific current UK Co-Trimoxazole 80 mg/400 mg per 5 mL Adult Suspension, the marketing authorisation holder is Aspen Pharma Trading Limited, Dublin, Ireland; the current UK patient leaflet identifies Aspen Bad Oldesloe GmbH, Germany as manufacturer.
These UK/Aspen details should not be presented as the confirmed manufacturer or marketing-authorisation holder of the current Egyptian SEPTRIN product. Publicly accessible Egyptian listings establish the association with Glaxo SmithKline Egypt but do not by themselves provide sufficiently authoritative evidence to define the present Egyptian regulatory MAH/manufacturing arrangement. That information should be verified against the current Egyptian package leaflet or Egyptian Drug Authority records.
The Egyptian Drug Authority provides official services for medicine-availability enquiries and drug-information enquiries.
8. Mechanism of Action
Co-trimoxazole acts by sequentially inhibiting microbial folate metabolism.
Sulfamethoxazole competitively inhibits utilization of PABA in the synthesis of dihydrofolate.
Trimethoprim reversibly inhibits dihydrofolate reductase and therefore reduces formation of tetrahydrofolate.
These mechanisms operate at consecutive stages of the same metabolic pathway, producing enhanced activity compared with either component acting alone against susceptible organisms. Depending on the organism and conditions, the overall effect may be bactericidal.
Trimethoprim has approximately 50,000-fold lower affinity for mammalian DHFR than for the corresponding bacterial enzyme.
9. Spectrum of Activity
Co-trimoxazole has activity against a variety of Gram-positive and Gram-negative organisms, but susceptibility varies substantially according to species, geography, time, indication and local resistance patterns.
Current UK product information lists commonly susceptible species including Staphylococcus aureus, Staphylococcus saprophyticus, Streptococcus pyogenes, Enterobacter cloacae, Haemophilus influenzae, Klebsiella oxytoca, Moraxella catarrhalis, Salmonella spp., Stenotrophomonas maltophilia and Yersinia spp.
Species for which acquired resistance may be a problem include Enterococcus faecalis, Enterococcus faecium, Nocardia spp., Staphylococcus epidermidis, Streptococcus pneumoniae, Citrobacter spp., Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus spp., Providencia spp. and Serratia marcescens.
The same current UK source classifies Pseudomonas aeruginosa, Shigella spp. and Vibrio cholerae as inherently resistant in its antibacterial-spectrum table.
Therefore, an organism's appearance in older susceptibility information does not establish that SEPTRIN is an appropriate current clinical treatment. Culture and susceptibility findings, current local epidemiology and applicable treatment guidelines should be considered whenever relevant.
10. Pharmacokinetics
Following oral administration, trimethoprim and sulfamethoxazole are rapidly and nearly completely absorbed.
Peak blood concentrations generally occur approximately 1–4 hours after ingestion, and food does not appear to delay absorption significantly.
Trimethoprim is approximately 50% protein bound and distributes extensively into tissues and body fluids. Tissue concentrations are generally higher than corresponding plasma concentrations, with particularly high concentrations in the lungs and kidneys.
Sulfamethoxazole is approximately 66% protein bound. It undergoes more extensive metabolism than trimethoprim through acetylation, oxidation and glucuronidation.
The principal elimination route of both components is renal. Approximately 50% of a trimethoprim dose is excreted unchanged in urine within 24 hours. Sulfamethoxazole and its metabolites are also predominantly recovered in urine.
Renal impairment prolongs trimethoprim elimination and the half-life of the major acetylated sulfamethoxazole metabolite. Dose reduction is recommended when creatinine clearance falls below specified thresholds in applicable product information.
Trimethoprim can also reduce renal tubular secretion of creatinine without an equivalent reduction in glomerular filtration. Consequently, measured serum creatinine may rise and estimated creatinine clearance may appear reduced without a corresponding true fall in GFR.
11. Indications
Current UK product information supports co-trimoxazole for selected infections caused by susceptible organisms and stresses consideration of official antimicrobial guidance.
Important current indications include:
Pneumocystis jirovecii pneumonitis/pneumonia
- Treatment of PJP/PCP
- Prevention/prophylaxis of PJP in appropriate patients.
Toxoplasmosis
Co-trimoxazole is indicated in the cited current UK product information for treatment and prophylaxis of toxoplasmosis.
Nocardiosis
Co-trimoxazole is indicated for treatment of nocardiosis.
Selected bacterial infections
The cited current UK SmPC permits treatment of the following infections where there is bacterial evidence of sensitivity to co-trimoxazole and good reason to prefer this combination over a single antibacterial agent:
- Acute uncomplicated urinary tract infections
- Acute otitis media
- Acute exacerbations of chronic bronchitis
Accordingly, co-trimoxazole should not be presented as a universally preferred first-line treatment for uncomplicated UTI or the other bacterial indications above; choice depends on susceptibility, patient factors, resistance patterns and applicable local guidance.
Older SEPTRIN product information included additional genital and gastrointestinal indications such as gonorrhoea, chancroid, granuloma inguinale, cholera, shigellosis and travellers' diarrhoea. These should not automatically be presented as current routine indications, because antimicrobial resistance and contemporary treatment recommendations have changed substantially.
12. Administration
SEPTRIN/co-trimoxazole oral formulations are administered orally.
For standard acute infections, the cited current UK Adult Suspension containing 80 mg trimethoprim + 400 mg sulfamethoxazole per 5 mL gives:
Adults (>18 years): 10 mL every 12 hours.
For children >12 to <18 years, the same formulation gives 10 mL every 12 hours and states that standard paediatric dosing approximates to 6 mg trimethoprim + 30 mg sulfamethoxazole/kg/day, divided into two equal doses.
For an equivalent 160 mg/800 mg double-strength dose, this corresponds pharmacologically to one D.S./Forte tablet per dose where the applicable tablet product information specifies the same standard regimen. Dosing should always follow the leaflet for the actual product being prescribed.
For renal impairment, the cited UK Adult Suspension recommends:
| Creatinine clearance | Recommended dose for this formulation |
|---|---|
| >30 mL/min | 10 mL every 12 hours |
| 15–30 mL/min | 5 mL every 12 hours |
| <15 mL/min | Not recommended |
PJP treatment requires substantially higher weight-based dosing. The cited current product information recommends approximately 20 mg trimethoprim + 100 mg sulfamethoxazole/kg/day, divided into two or more doses for two weeks.
Co-trimoxazole may preferably be taken with food or drink to minimize gastrointestinal disturbance. Adequate urinary output should be maintained because crystalluria, although uncommon, can occur.
For standard acute infections, current UK product information states that treatment should continue until the patient has been symptom-free for two days; most patients require treatment for at least five days, and lack of clinical improvement after seven days warrants reassessment.
All dosing information must be interpreted according to the specific strength and formulation actually being used. In particular, the Egyptian 40/200 mg per 5 mL suspension is half the concentration of the cited UK 80/400 mg per 5 mL Adult Suspension and therefore the volume instructions above must not be transferred directly between the two products.
13. Method of Preparation
The oral suspension must be handled according to the instructions for the specific marketed product.
The cited current UK 80/400 mg per 5 mL Adult Suspension is supplied as an oral suspension rather than a powder requiring routine reconstitution. Its SmPC states that it may be diluted with Syrup BP; although some sedimentation may occur, such dilution remains stable for at least one month, and the suspension should be shaken thoroughly before use.
This instruction is specific to that UK formulation. It should not automatically be applied to the Egyptian 40/200 mg per 5 mL SEPTRIN suspension, whose concentration, excipients, packaging and product-specific handling instructions may differ.
For Egyptian products, the instructions supplied with the actual marketed package should take precedence.
14. Contraindications
According to the cited current UK SmPC, co-trimoxazole should not be used in patients with:
- Known hypersensitivity to sulfonamides, trimethoprim, co-trimoxazole or relevant excipients.
- Previous drug-induced immune thrombocytopenia associated with trimethoprim and/or sulfonamides.
- Severe impairment of liver function.
- Severe renal insufficiency where repeated measurement of plasma concentrations cannot be performed.
- Acute porphyria.
- Infants during the first six weeks of life.
- First-trimester pregnancy.
Contraindication wording can differ between regulatory jurisdictions and formulations, particularly for pregnancy, renal impairment and minimum paediatric age. The locally approved Egyptian product information should therefore be followed for the Egyptian product.
15. Warnings & Precautions
Co-trimoxazole can produce rare but potentially life-threatening adverse reactions.
Fatalities, although very rare, have occurred from reactions including Stevens–Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anaemia, other serious blood dyscrasias and respiratory hypersensitivity.
Patients should discontinue treatment and obtain prompt medical assessment if they develop a significant or progressive rash, blistering, mucosal lesions, fever associated with rash, jaundice, unexplained bruising, severe sore throat, breathing difficulty, or other manifestations suggestive of serious hypersensitivity or systemic toxicity.
Important warnings include:
Severe cutaneous adverse reactions
Reported reactions include:
- Stevens–Johnson syndrome (SJS)
- Toxic epidermal necrolysis (TEN)
- Drug reaction with eosinophilia and systemic symptoms (DRESS)
- Acute generalized exanthematous pustulosis (AGEP)
The highest risk of SJS/TEN occurs during the early weeks of treatment. If SJS, TEN or DRESS occurs, co-trimoxazole must be discontinued, and patients who have experienced these reactions with co-trimoxazole should not be re-exposed. AGEP also requires cessation and contraindicates subsequent administration.
Haemophagocytic lymphohistiocytosis (HLH)
Very rare cases of HLH have been reported with co-trimoxazole. HLH is a potentially life-threatening syndrome of pathological immune activation. Patients with manifestations suggestive of excessive systemic inflammation should be evaluated promptly; if HLH is diagnosed, co-trimoxazole should be discontinued.
Severe respiratory toxicity
Very rare severe respiratory reactions, sometimes progressing to acute respiratory distress syndrome (ARDS), have been reported. New cough, fever, dyspnoea, pulmonary infiltrates or deterioration in pulmonary function during treatment require prompt evaluation; co-trimoxazole should be discontinued when serious respiratory toxicity is suspected according to the product information.
Renal impairment
Dose adjustment may be required. Monitoring is particularly important in patients with impaired renal function.
Urinary output
Adequate urinary output should be maintained. Crystalluria is uncommon but has been documented, with potentially greater risk in malnourished patients.
Hyperkalaemia
Trimethoprim can cause clinically important increases in serum potassium, especially in patients with renal impairment or those receiving other potassium-raising medicines.
Hyponatraemia and metabolic acidosis
Hyponatraemia can occur, and co-trimoxazole has also been associated with metabolic acidosis when other possible causes have been excluded. Monitoring is particularly important in susceptible patients.
Haematological toxicity
Leukopenia, neutropenia, thrombocytopenia, agranulocytosis, megaloblastic anaemia, aplastic anaemia and other serious blood abnormalities have been reported. Monthly blood counts are advisable during prolonged treatment and in folate-deficient or older patients.
G6PD deficiency
Haemolysis may occur in patients with glucose-6-phosphate dehydrogenase deficiency.
Liver disease
Serious hepatic reactions, including cholestatic jaundice and hepatic necrosis, have been reported; hepatic necrosis may be fatal.
Severe atopy or bronchial asthma
Co-trimoxazole should be administered cautiously in patients with severe atopy or bronchial asthma.
Group A streptococcal pharyngitis
Co-trimoxazole should not be used to treat pharyngitis caused by Group A β-haemolytic streptococci because eradication from the oropharynx is less effective than with penicillin.
Antimicrobial stewardship
The combination should be used only when its expected benefit outweighs the risks and, for relevant bacterial infections, consideration should be given to using a single effective antibacterial agent instead.
16. Drug Interactions
Important clinically relevant interactions include:
Warfarin: co-trimoxazole can potentiate warfarin's anticoagulant action; careful anticoagulation monitoring is advisable.
Phenytoin: co-trimoxazole prolongs phenytoin half-life and may result in excessive phenytoin effects. Clinical status and serum concentrations should be monitored where appropriate.
Digoxin: trimethoprim can increase plasma digoxin concentrations, particularly in older patients.
Methotrexate: co-trimoxazole may increase free plasma methotrexate levels and trimethoprim can interfere with certain methotrexate assays. Combined antifolate effects also require particular caution.
ACE inhibitors, angiotensin-receptor blockers and potassium-sparing diuretics such as spironolactone: concomitant use can increase the risk of clinically important hyperkalaemia.
Sulfonylureas and repaglinide: potentiation of glucose-lowering effects and hypoglycaemia may occur.
Cyclosporine: reversible deterioration in renal function has been reported after renal transplantation.
Pyrimethamine: patients receiving more than 25 mg weekly have been reported to develop megaloblastic anaemia when co-trimoxazole is given concurrently.
Zidovudine: concomitant therapy may increase the risk of haematological adverse reactions, and haematological monitoring should be considered.
Lamivudine: trimethoprim/sulfamethoxazole 160/800 mg increases lamivudine exposure by approximately 40% because of the trimethoprim component.
Azathioprine: conflicting clinical reports describe interactions between azathioprine and trimethoprim/sulfamethoxazole resulting in serious haematological abnormalities.
Folinic acid: supplementation with folinic acid has been shown to interfere with the antimicrobial efficacy of trimethoprim/sulfamethoxazole, particularly during PJP treatment and prophylaxis. Although folinic acid may be considered in selected circumstances such as folate-related haematological toxicity, its use requires clinical judgment.
Rifampicin: concurrent use can shorten the plasma half-life of trimethoprim after approximately one week; the cited UK SmPC states that this is not thought to be clinically significant.
Procainamide and amantadine: because trimethoprim and these drugs may share active renal-secretory pathways, concurrent use can increase plasma concentrations of one or both agents.
Thiazide diuretics: older patients receiving thiazides concomitantly may have an increased risk of thrombocytopenia, with or without purpura.
Dofetilide: current U.S. prescribing information lists concurrent administration with trimethoprim/sulfamethoxazole as contraindicated because increased dofetilide exposure can lead to serious ventricular arrhythmias, including torsade de pointes.
The interaction profile is extensive, and a patient's complete medication list should be reviewed before prescribing.
17. Side Effects
Common adverse effects listed in current product information include:
- Nausea
- Diarrhoea
- Headache
- Skin rash
- Fungal overgrowth
Important rare, very rare or frequency-not-known adverse reactions include:
- Stevens–Johnson syndrome
- Toxic epidermal necrolysis
- DRESS
- AGEP
- Sweet's syndrome
- Anaphylactic reactions
- Thrombocytopenia
- Agranulocytosis
- Aplastic anaemia
- Haemolytic anaemia
- Megaloblastic anaemia
- Methaemoglobinaemia
- Hyperkalaemia
- Hyponatraemia
- Hypoglycaemia
- Metabolic acidosis
- Cholestatic jaundice
- Hepatic necrosis
- Renal impairment
- Tubulointerstitial nephritis
- Renal tubular acidosis
- Aseptic meningitis
- Peripheral neuropathy
- Seizures
- Pulmonary hypersensitivity
- Severe respiratory toxicity/ARDS
- Pancreatitis
- Pseudomembranous colitis
- Rhabdomyolysis, particularly in association with high-dose PJP management
- Circulatory shock in reported cases, particularly among immunocompromised patients.
Haemophagocytic lymphohistiocytosis (HLH) has also been reported very rarely during co-trimoxazole treatment and represents a potentially life-threatening immune-activation syndrome requiring immediate assessment and discontinuation when diagnosed.
A skin rash should never automatically be assumed to be harmless, because serious cutaneous adverse reactions may initially present with relatively nonspecific dermatological symptoms.
18. Use in Special Populations
Children
Paediatric dosing depends on age, weight, formulation and indication. The cited current UK product information contraindicates co-trimoxazole in infants during the first six weeks of life. Other jurisdictions or products may specify different minimum ages, so the applicable local product information must be followed.
Elderly patients
Older adults are more susceptible to adverse reactions, particularly where renal or hepatic impairment or concomitant medication is present. Particular attention should be paid to renal function, electrolyte abnormalities and haematological toxicity.
Renal impairment
Dosage reduction and monitoring may be necessary. The cited UK SmPC lists severe renal insufficiency as a contraindication when repeated plasma-concentration measurements cannot be performed.
Hepatic impairment
Severe impairment of liver function is a contraindication in the cited current UK product information.
Pregnancy
Trimethoprim is a folate antagonist.
The cited current UK SmPC states that trimethoprim/co-trimoxazole is contraindicated during the first trimester of pregnancy. Epidemiological evidence described in that SmPC reports increased risks of spontaneous abortion and congenital malformations, including neural-tube defects, oral clefts and cardiovascular defects, after first-trimester trimethoprim exposure.
During the second and third trimesters, co-trimoxazole should be avoided unless clinically necessary. Folate supplementation should be considered if it is used during pregnancy.
Sulfamethoxazole competes with bilirubin for albumin binding. Administration near delivery may therefore theoretically precipitate or worsen neonatal hyperbilirubinaemia and kernicterus, especially in premature infants or infants with G6PD deficiency.
Pregnancy recommendations can differ between jurisdictions, so the locally approved product information and the patient's clinical circumstances must be considered.
Breastfeeding
Trimethoprim and sulfamethoxazole are excreted into breast milk. The cited UK SmPC recommends avoiding co-trimoxazole in lactating mothers when either the mother or infant has, or is at particular risk of developing, hyperbilirubinaemia. It also advises avoiding administration to infants younger than eight weeks because of their predisposition to hyperbilirubinaemia.
G6PD deficiency
Haemolysis may occur in patients with G6PD deficiency; particular caution is required.
19. Storage Conditions
Storage requirements depend on the exact formulation, manufacturer and country-specific product information.
For the specific current UK Co-Trimoxazole 80 mg/400 mg per 5 mL Adult Suspension cited here, the SmPC states:
- Store below 25°C.
- Protect from light.
These storage conditions should not automatically be presented as the confirmed storage instructions for the Egyptian SEPTRIN products unless the current Egyptian package or leaflet states the same requirements.
Egyptian retail information for SEPTRIN D.S. advises storage at room temperature away from heat and light, but the official instructions printed on the actual Egyptian product should take precedence over online retail information.
20. Additional Sections
Antimicrobial stewardship
SEPTRIN/co-trimoxazole should not be used simply because it has broad antimicrobial activity. For relevant bacterial infections, current product information specifically advises considering whether a single effective antibacterial agent would be preferable.
Monitoring
Depending on dose, treatment duration, indication, renal function, concomitant medicines and other patient-specific risks, appropriate monitoring may include:
- Renal function
- Serum potassium and sodium
- Complete blood count
- Liver function where clinically indicated
- INR/anticoagulation status in patients receiving warfarin
- Phenytoin concentrations where appropriate
- Digoxin concentrations where appropriate
- Sulfamethoxazole concentrations in selected patients with renal impairment or high-dose therapy according to product-specific recommendations.
Overdose
Acute overdose may cause nausea, vomiting, dizziness and confusion. Bone-marrow depression has been reported in acute trimethoprim overdose.
Management is supportive and depends on clinical circumstances and renal function. Both trimethoprim and active sulfamethoxazole are moderately dialysable by haemodialysis; peritoneal dialysis is not effective.
Resistance
Resistance to trimethoprim/sulfamethoxazole varies substantially between organisms, locations and time periods. Susceptibility information should therefore be interpreted using current local epidemiology and microbiological data rather than relying exclusively on historical susceptibility lists.
Driving and operating machinery
No dedicated studies have established the effects of co-trimoxazole on driving performance or ability to operate machinery. The patient's clinical status and possible adverse effects should nevertheless be considered when evaluating whether these activities can be performed safely.
Excipients
Excipients vary between products and formulations.
For example, the cited UK 80/400 mg per 5 mL Adult Suspension contains sucrose, methyl hydroxybenzoate and a small amount of ethanol, among other excipients. These excipient details are specific to that product and should not be assumed to apply to the Egyptian SEPTRIN suspension or tablets.
Patients with relevant allergies, metabolic disorders or excipient sensitivities should check the leaflet of the actual product being used.
21. Frequently Asked Questions (FAQ)
What is SEPTRIN?
SEPTRIN is a brand of co-trimoxazole, a fixed combination of trimethoprim and sulfamethoxazole.
Is SEPTRIN an antibiotic?
Yes. It is an antibacterial combination belonging to the sulfonamide-and-trimethoprim class.
What is SEPTRIN D.S.?
The Egyptian SEPTRIN D.S. product currently identified in accessible drug databases contains 160 mg trimethoprim + 800 mg sulfamethoxazole per tablet.
What is the Egyptian SEPTRIN oral suspension strength?
The Egyptian product currently identified in accessible drug databases contains 40 mg trimethoprim + 200 mg sulfamethoxazole per 5 mL.
Is the 80/400 mg per 5 mL Adult Suspension the same product as the Egyptian 40/200 mg per 5 mL suspension?
No. The cited UK Adult Suspension contains 80 mg trimethoprim + 400 mg sulfamethoxazole per 5 mL, whereas the currently identified Egyptian SEPTRIN suspension contains 40 mg + 200 mg per 5 mL. The UK suspension is therefore twice as concentrated per millilitre, and dosing volumes must not be transferred directly between the two formulations.
Can SEPTRIN be used for viral infections?
No. It is an antibacterial medication and does not treat viral infections such as the common cold or influenza.
Can SEPTRIN cause high potassium?
Yes. Trimethoprim can cause hyperkalaemia, particularly in patients with renal impairment or patients receiving medicines that increase serum potassium.
Can SEPTRIN cause serious skin reactions?
Yes. Rare but potentially life-threatening reactions including SJS, TEN, DRESS and AGEP have been reported. Prompt discontinuation and medical evaluation are required if signs of a severe cutaneous reaction develop.
Can SEPTRIN cause HLH?
Very rare cases of haemophagocytic lymphohistiocytosis (HLH) have been reported during co-trimoxazole treatment. HLH is potentially life-threatening and requires urgent evaluation; treatment should be discontinued if HLH is diagnosed.
Is SEPTRIN safe during pregnancy?
Use requires particular caution. The cited current UK SmPC contraindicates co-trimoxazole during the first trimester and advises avoiding it during the second and third trimesters unless clinically necessary. Local prescribing information and individual clinical circumstances must be considered.
Can SEPTRIN be used in kidney disease?
It may require dose reduction and additional monitoring. Severe renal impairment may make treatment inappropriate where adequate plasma-concentration monitoring cannot be performed.
Does SEPTRIN interact with warfarin?
Yes. It can potentiate warfarin's anticoagulant effect, so careful anticoagulation monitoring is advisable.
Can folinic acid always be given to prevent blood-related adverse effects?
No. Although folinic acid may be considered in selected circumstances, current product information warns that folinic acid supplementation can interfere with the antimicrobial efficacy of trimethoprim/sulfamethoxazole, particularly in the treatment and prophylaxis of PJP.
Is SEPTRIN still available in Egypt?
Current online Egyptian drug databases identify both SEPTRIN D.S. 800/160 mg tablets and SEPTRIN oral suspension 200/40 mg per 5 mL, and Egyptian retail information also lists SEPTRIN D.S. However, online listing does not guarantee real-time pharmacy availability or establish current regulatory status. The Egyptian Drug Authority provides an official service specifically for enquiries about medicine availability in the Egyptian market.
22. References
- SEPTRIN™ Product Information — GDS20/IP04, GlaxoSmithKline, date of issue: 20 November 2007. Product information covering SEPTRIN formulations, pharmacology, indications, administration, contraindications, warnings, interactions, adverse reactions, pharmacokinetics and storage.
- Co-Trimoxazole 80 mg/400 mg per 5 mL Adult Suspension — Summary of Product Characteristics (SmPC), Aspen / electronic Medicines Compendium (emc). The SmPC states January 2026 as the date of revision of the text; the emc page records 07 April 2026 as its latest website update. It provides current UK indications, dosage, contraindications, warnings, interactions, pregnancy information, adverse reactions, pharmacokinetics, storage requirements and marketing-authorisation information.
- Co-Trimoxazole 40 mg/200 mg per 5 mL Paediatric Suspension — Summary of Product Characteristics, Aspen / emc. Current UK paediatric co-trimoxazole product information, including updated safety warnings such as HLH and severe respiratory toxicity.
- Co-Trimoxazole 160 mg/800 mg Forte Tablets — Summary of Product Characteristics, Aspen / emc. Current UK double-strength tablet product information, including contemporary serious-adverse-reaction warnings.
- DailyMed — Sulfamethoxazole and Trimethoprim Tablets, current U.S. prescribing information. Provides U.S.-specific interaction and safety information, including contraindicated coadministration with dofetilide.
- Aspen Pharmacare — GSK/Aspen strategic transaction information. Aspen documents that it acquired worldwide distribution rights to Septrin among a group of specialist branded products in transactions completed in 2009.
- Vademecum — SEPTRIN DS Tablet 800 mg + 160 mg, Egypt. Identifies the Egyptian tablet product, oral route, ATC J01EE01 and Glaxo SmithKline Egypt as the associated laboratory/company.
- Vademecum — SEPTRIN Oral Suspension 200 mg/5 mL + 40 mg/5 mL, Egypt. Identifies the Egyptian oral-suspension strength and Glaxo SmithKline Egypt as the associated laboratory/company.
- Vezeeta Pharmacy Egypt — SEPTRIN D.S. 10 Coated Tablets. Current Egyptian retail listing confirming the presence of the SEPTRIN D.S. product in an Egyptian pharmacy catalogue and identifying Glaxo SmithKline as manufacturer in that listing.
- Egyptian Drug Authority — Medicine Availability and Drug Information Services. Official Egyptian authority service for enquiries regarding medicine availability and reliable drug information in the Egyptian market.