Sulphamethoxazole is antibacterial sulfonamide. Sulphamethoxazole is classified as an intermediate-acting sulfonamide and is longer-acting than sulfisoxazole, which allows it to be given 2-3 times daily, possibly aiding in compliance. Although it was once an extremely useful antibiotic, the development of resistance and the availability of newer agents has made sulfamethoxazole almost obsolete as a single agent. Today, clinical use of sulfamethoxazole occurs primarily in combination with trimethoprim. It was approved by the FDA in 1961 as an antibecterial agent. Sulphamethoxazole is effective against gram positive, gram negative bacteria and some protozoan.
Sulphamethoxazole also known as Sulfamethoxazole. . It is of Synthetic origin and belongs to Sulphonamide. It belongs to Dihyropteroate 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.
Oral absorption of Sulphamethoxazole is found to be 100% . Volume of distribution is found to be 0.21 l/kg and plasma protien binding is 65%. and metabolism is reported Hepatic. Renal Excretion accounts for 80 - 85% and plasma half life is 7-12 hr.
Sulphamethoxazole is known to interact with other drugs, the details of drug interactions is as follows:
Drug Details Severity Onset Management Clozapine Co-Trimoxazole Fluconazole Lamivudine Norgestimate Para Aminobenzoic Acid Should not be used concurrently except on medical advice. Phenytoin (Na) Prilocaine Procaine Decreased effect of sulfonamides with the PABA metabolite of procaine. Trimethoprim Warfarin (Na) Sulphamethoxazole may decrease the metabolism of Warfarin. Moderate Monitor 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.
Interference in Pathology
Measurement of serum Theophylline levels by HPLC
The severe or irreversible adverse effects of Sulphamethoxazole, which give rise to further complications include Hepatic damage, Renal failure, Crystalluria.
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 Nausea, Vomiting, Confusion, Dizziness, Abdominal pain.
The symptomatic adverse reactions produced by Sulphamethoxazole are more or less tolerable and if they become severe, they can be treated symptomatically, these include Rashes, Hemolytic anemia, Thrombocytopenia, Eosinophilia, Serum sickness, Hypoprothrombinemia, Hematological disorder.
Sulphamethoxazole's dosage details are as follows:
800 mg 800 (800) 12 hourly PO In Combination with trimethoprim 160 mg/day.
Paedriatic Dosage ( 20 Kg. )
25 to 30 mg/kg 28 (27.5) 12 hourly Oral Maintenance, As required
50 to 60 mg/kg 55 (55) 24 hourly Oral Initial
Neonatal Dosage ( 3 Kg. )
Should not be used in this age group
High Risk Groups
Drug should not be given to Paediatrics, Pregnant Mothers, patients suffering from Kidney dysfunction, patients suffering from Liver Malfunction, Geriatrics, and Neonates.
If prescribing authority justifies the benefits of the drug against the possible damages he/she should reevaluate them and consult the reference material and previous studies.
Warning / Precautions
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.
Store at room temperature. Do not Freeze. Protect from Sunlight.
Store at room temperature. Protect from Sunlight and Moisture.
powered by Disqus. comments powered by