Drug Identity
Active Ingredient
Sulphamethoxazole 400Mg
Chemical Class
Sulphonamide
Pharmacological Group
on the basis of mechanism of action and also cl...
ATC Code
J01EA01
Status
Essential Medicine
What is Primox?
Uses
Sulphamethoxazole is antibacterial sulfonamide. Sulphamethoxazole is classified as an intermediate-acting sulfonamide and is longer-actin...
How It Works
Chemical Class
Sulphonamide
Pharmacological Group
on the basis of mechanism of action and also classified in Antibacterial pharmacological group
Sulphamethoxazole also known as Sulfamethoxazole. It is of Synthetic origin and belongs to Sulphonamide. It belongs to Dihydropteroate synthetase inhibitor pharmacological group on the basis of mechanism of action and also classified in Antibacterial pharmacological group. The Molecular Weight of Sulphamethoxazole is 253.30. Its pKa is 5.7.
How to Take It
1
Adult · PO
800 mg — 12 hourly
In Combination with trimethoprim 160 mg/day.
2
Child · Oral
25 to 30 mg/kg — 12 hourly
Maintenance, As required
3
Child · Oral
50 to 60 mg/kg — 24 hourly
Initial
Safety Alerts
Sulphamethoxazole is contraindicated in conditions like Renal diseases, Liver diseases
Important Warnings
Sulphamethoxazole should be used with caution in patients with medical history including liver or kidney disease, blood disorders or of any drug allergy
This may makes patients more prone to sunburn, wear protective clothing and (PABA-free) sunscreen when outdoors
It should be used only if clearly needed during pregnancy or lactation
Side Effects
The severe or irreversible adverse effects of Sulphamethoxazolewhich give rise to further complications include Hepatic damageRenal failureCrystalluria. Sulphamethoxazole produces potentially life-threatening effects which include Stevens Johnson syndrome. which are responsible for the discontinuation of Sulphamethoxazole therapy. The signs and symptoms that are produced after the acute overdosage of Sulphamethoxazole include NauseaVomitingConfusionDizzinessAbdominal pain. The symptomatic adverse reactions produced by Sulphamethoxazole are more or less tolerable and if they become severethey can be treated symptomaticallythese include RashesHemolytic anemiaThrombocytopeniaEosinophiliaSerum sicknessHypoprothrombinemia
Drug Interactions
Sulphamethoxazole is known to interact with other drugs
the details of drug interactions is as follows:DrugDetailsSeverityOnsetManagementClozapineCo-TrimoxazoleFluconazoleLamivudineNorgestimatePara Aminobenzoic AcidShould not be used concurrently except on medical advice.Phenytoin (Na)PrilocaineProcaineDecreased effect of sulfonamides with the PABA metabolite of procaine.TrimethoprimWarfarin (Na)Sulphamethoxazole may decrease the metabolism of Warfarin. ModerateMonitor for increased effects of Warfarin if Sulphamethoxazole is initiated/dose increased
and decreased effects if Sulphamethoxazole is discontinued/dose decreased. These interactions are sometimes beneficial and sometimes may pose threats to life. Always consult your physician for the change of dose regimen or an alternative drug of choice that may strictly be required.
Storage
Inj Store at room temperature. Do not Freeze. Protect from Sunlight. Tab, Susp Store at room temperature. Protect from Sunlight and Moisture.
Price Intelligence
Rs 268.49
DRAP approved maximum price · per pack of 200 · approved 23 Jul, 2026
No retail price observed for this pack. Retailers may not exceed the approved maximum.
Prices across sources
DRAPper pack of 200Rs 268.49
Should you consider an alternative?
Other options containing Sulphamethoxazole 400Mg, and what they are not.
Identical active ingredient at the same strength. Cheapest per unit first.
Supracombin
400mg
Rs 713.49
SEARLE PAKISTAN (PVT.) LTD.
COTRIZA
400mg
Rs 805.86 ceiling
No DRAP alertsMS SIZA INTERNATIONAL PVT LTD.
Mactran
400mg
Rs 305.81 ceiling
Macter International Limited
Ordered by lowest price per unit where a pack size is known, then by price. Order is never affected by sponsorship. Not medical advice — confirm any change with your pharmacist or doctor.
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