Sulfamethoprim Drug Information [ Par Pharmaceutical ]

Table of content

Sulfamethoprim category:

• Human
• Macrolides
• Urinary Anti-Infectives

Active ingredients:

• Sulfamethoxazole
• Trimethoprim

Sulfamethoprim companies and manufacturers:

• Par Pharmaceutical

General Information

Sulfamethoprim forms, composition and dosages:

• Tablet; Oral; Sulfamethoxazole 400 mg; Trimethoprim 80 mg

Indications, usages and classification codes:

• J01EE01 - Sulfamethoxazole and Trimethoprim

There is an additional general information about this medication active ingredient co-trimoxazole (sulfamethoxazole + trimethoprim):

Pharmacological action

Synthetic antimicrobial drug with broad spectrum bactericidal action. sulfamethoxazole has a bacteriostatic action, which is associated with inhibition of recycling process of PABA and a violation dihydrofolic acid's synthesis in bacterial cells. Trimethoprim inhibits the enzyme that is involved in the metabolism of folic acid converting dihydrofolate to tetrahydrofolate. Thus it is blocked two successive stages of the biosynthesis of purines and therefore nucleic acids that are essential for growth and reproduction of bacteria. High concentrations created in the tissues of the lung, kidney, prostate, cerebrospinal fluid, bile, bones.
Co-trimoxazole is active against gram-positive bacteria: Staphylococcus spp. (including strains of penicillinase producing), Streptococcus spp. (including Streptococcus pneumoniae), Corynebacterium diphtheriae; gram-negative bacteria: Neisseria gonorrhoeae, Escherichia coli, Shigella spp., Salmonella spp., Proteus spp., Enterobacter spp., Klebsiella spp., Yersinia spp., Vibrio cholerae, Haemophilus influenzae; anaerobic asporogenous bacteria - Bacteroides spp. Co-trimoxazole is active also against Chlamydia spp.
Pseudomonas aeruginosa, Treponema spp., Mycoplasma spp., Mycobacterium tuberculosis and also viruses and fungi are resistant to co-trimoxazole.

Pharmacokinetics

After oral administration sulfamethoxazole and trimethoprim is rapidly absorbed from the gastrointestinal tract. Meal slows their absorption. Widely distributed in tissues and body fluids. The binding of trimethoprim to plasma proteins is 50%, sulfamethoxazole - 66%. T1/2 of trimethoprim is 8.6-17 hours, sulfamethoxazole - 9-11 hours. Trimethoprim is excreted in the urine in unchanged form (50%) and as metabolites. Sulfamethoxazole also excreted in the urine, mainly unchanged.

Why is Sulfamethoprim by Par Pharmaceutical prescribed?

Infectious-inflammatory diseases caused by sensitive to co-trimoxazole microorganisms: respiratory tract infections (including acute and chronic bronchitis, empyema, bronchiectasis, lung abscess, pneumonia, tonsillitis, pharyngitis); urinary tract infections (including gonococcal urethritis), cystitis, pyelonephritis, prostatitis; gastrointestinal infections (including enteritis, typhoid, paratyphoid, dysentery, cholecystitis, cholangitis); infections of skin and soft tissue (including pyoderma, furunculosis, wound infection), septicemia, brucellosis.

Dosage and administration

Individual. Doses are given on the basis of sulfamethoxazole. For oral administration for adults and children older than 12 years the average dose is 0.4-2 g every 12 hours (2 times / day), course of treatment - 5-14 days. Orally for children aged 2-5 months - 100 mg 2 times / day; 1-2 years - 100 mg 2 times / day; 3-6 years - 200 mg 2 times / day; 6-12 years at 200-400 mg 2 times / day.
Parenterally administered only in the absence of the possibility of oral administration. IM for adults and children over 12 years - 800 mg every 12 hours; for children aged 6-12 years - 30 mg / kg / day, interval between each dose - 12 hours.
If necessary prescribed IV as drops at 0.8-1.6 g every 12 hours (2 times / day) within 5 days. For children aged 6-12 years are prescribed at 15 mg / kg every 12 hours. Average duration of injection - 30-60 minutes but no more than 1.5 hours. The course of treatment is average 5 days, then if necessary go to oral administration. The maximum oral daily dose for adults is 3.6 g.

Sulfamethoprim by Par Pharmaceutical side effects

Digestive system: nausea, vomiting, diarrhea, glossitis, pseudomembranous colitis, cholestatic hepatitis.
Allergic reactions: skin rash, angioedema, Stevens-Johnson syndrome, Lyell's syndrome.
Hemopoietic system: leukopenia, neutropenia, thrombocytopenia, agranulocytosis, megaloblastic anemia.
Urinary system: crystalluria, hematuria, interstitial nephritis.
Local reactions: phlebitis (when IV injected).
Other: purpura, impaired thyroid function.

Contraindications

Expressed disorders of liver and kidney function, blood diseases, deficiency of glucose-6-phosphate dehydrogenase, pregnancy, lactation (breastfeeding), hypersensitivity to sulfonamides and trimethoprim.

Using during pregnancy and breastfeeding

Sulfonamides and trimethoprim cross the placenta and excreted in breast milk. They can cause the development of kernicterus and hemolytic anemia in the fetus and newborn. In addition increases the risk of fatty liver in pregnant women. Therefore the use of co-trimoxazole in pregnancy is contraindicated. If necessary using of co-trimoxazole during lactation breastfeeding should be discontinued.

Special instructions

With careful use of co-trimoxazole in patients with a possible deficiency of folic acid, in allergic reactions in anamnesis, bronchial asthma, disorders of liver, kidney, thyroid gland. When long treatment should be systematically study the peripheral blood, the functional state of liver and kidney.
Elderly patients are recommended the appointment of additional folic acid. During co-trimoxazole treatment should be ensured adequate water pressure (to avoid the development of crystalluria).
If the kidney function disorders the dose should be reduced and the intervals between doses increased.
The risk of adverse reactions is increased in elderly patients and patients with AIDS.
When parenteral administration in patients with renal insufficiency should determine the concentration of sulfamethoxazole in blood plasma every 2-3 days before the regular IM injection. In concentration of 150 ug / ml the treatment should be discontinued until the concentration drops to 120 mcg / ml.

Sulfamethoprim by Par Pharmaceutical drug interactions

With the simultaneous application of co-trimoxazole effect of anticoagulants of indirect action is greatly enhanced due to slow inactivation of the latter, as well as their release from binding with plasma proteins.
In an application with some sulfonylureas may increase hypoglycemic effect which is associated with an increased concentration of free fraction of co-trimoxazole.
The simultaneous use of co-trimoxazole and methotrexate may increase the toxicity of the latter (in particular to the appearance of pancytopenia) due to its release from binding to plasma proteins.
Influenced butadion, indomethacin, naproxen, salicylates and other NSAIDs may increase the action co-trimoxazole with the development of undesirable effects, since there release of active substances from binding with blood proteins and increase their concentration.
Simultaneous treatment with diuretics and co-trimoxazole increases the risk of thrombocytopenia caused by the latter especially in elderly patients.
In the case of co-administration chloridine with co-trimoxazole antimicrobial effect is enhanced because chloridine inhibits the formation of tetrahydrofolic acid required for the synthesis of nucleic acids and proteins. In turn sulfonamides inhibit the formation of dihydrofolic acid, a precursor of tetrahydrofolic acid. This combination is widely used in the treatment of toxoplasmosis.
Absorption of sulfamethoxazole and trimethoprim at their joint reception with cholestyramine decreases the formation of insoluble complexes, which leads to a decrease in their concentration in the blood.

Sulfamethoprim by Par Pharmaceutical in case of emergency / overdose

Symptoms: anorexia, nausea, vomiting, weakness, abdominal pain, headache, drowsiness, hematuria and crystalluria.
Treatment: gastric lavage, fluid management, correction of electrolyte imbalance. If necessary - hemodialysis.
For chronic overdosage is characterized bone marrow suppression (pancytopenia). Treatment and prevention: the appointment of folic acid (5-15 mg daily).

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