Co-Trimoxazole Actions

• Actions of Co-Trimoxazole in details
• Co-Trimoxazole administration
• Co-Trimoxazole pharmacology
• Co-Trimoxazole reviews

Actions of Co-Trimoxazole in details

Co-Trimoxazole Lafayette Pharmaceutical Laboratory is a synthetic antimicrobial drug with broad spectrum bactericidal action. Sulfamethoxazole (Co-Trimoxazole) 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 (Co-Trimoxazole) 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.

How should I take Co-Trimoxazole?

Take Co-Trimoxazole exactly as prescribed by your doctor. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Shake the oral suspension (liquid) well just before you measure a dose. Measure the liquid with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

Use Co-Trimoxazole for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Co-Trimoxazole will not treat a viral infection such as the common cold or flu.

Drink plenty of fluids to prevent kidney stones while you are taking Trimethoprim (Co-Trimoxazole) and Sulfamethoxazole (Co-Trimoxazole).

Co-Trimoxazole can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using Co-Trimoxazole.

Store at room temperature away from moisture, heat, and light.

Co-Trimoxazole administration

Take exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.

Measure liquid medicine with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.

Take this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Sulfamethoxazole (Co-Trimoxazole) and Trimethoprim (Co-Trimoxazole) will not treat a viral infection such as the common cold or flu.

Drink plenty of fluids to prevent kidney stones while you are taking Trimethoprim (Co-Trimoxazole) and Sulfamethoxazole (Co-Trimoxazole).

This medication can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using Sulfamethoxazole (Co-Trimoxazole) and Trimethoprim (Co-Trimoxazole).

Store at room temperature away from moisture, heat, and light.

Co-Trimoxazole pharmacology

Co-Trimoxazole is rapidly absorbed following oral administration. Both Sulfamethoxazole (Co-Trimoxazole) and Trimethoprim (Co-Trimoxazole) exist in the blood as unbound, protein-bound, and metabolized forms; Sulfamethoxazole (Co-Trimoxazole) also exists as the conjugated form. The metabolism of Sulfamethoxazole (Co-Trimoxazole) occurs predominately by N4-acetylation, although the glucuronide conjugate has been identified. The principal metabolites of Trimethoprim (Co-Trimoxazole) are the 1- and 3-oxides and the 3'- and 4'-hydroxy derivatives. The free forms of Sulfamethoxazole (Co-Trimoxazole) and Trimethoprim (Co-Trimoxazole) are considered to be the therapeutically active forms. Approximately 44% of Trimethoprim (Co-Trimoxazole) and 70% of Sulfamethoxazole (Co-Trimoxazole) are bound to plasma proteins. The presence of 10 mg percent Sulfamethoxazole (Co-Trimoxazole) in plasma decreases the protein binding of Trimethoprim (Co-Trimoxazole) by an insignificant degree; Trimethoprim (Co-Trimoxazole) does not influence the protein binding of Sulfamethoxazole (Co-Trimoxazole).

Peak blood levels for the individual components occur 1 to 4 hours after oral administration. The mean serum half-lives of Sulfamethoxazole (Co-Trimoxazole) and Trimethoprim (Co-Trimoxazole) are 10 and 8 to 10 hours, respectively. However, patients with severely impaired renal function exhibit an increase in the half-lives of both components, requiring dosage regimen adjustment. Detectable amounts of Trimethoprim (Co-Trimoxazole) and Sulfamethoxazole (Co-Trimoxazole) are present in the blood 24 hours after drug administration. During administration of 160 mg Trimethoprim (Co-Trimoxazole) and 800 mg Sulfamethoxazole (Co-Trimoxazole) b.i.d., the mean steady-state plasma concentration of Trimethoprim (Co-Trimoxazole) was 1.72 mcg/mL. The steady-state minimal plasma levels of free and total Sulfamethoxazole (Co-Trimoxazole) were 57.4 mcg/mL and 68.0 mcg/mL, respectively. These steady-state levels were achieved after 3 days of drug administration.1

Excretion of Sulfamethoxazole (Co-Trimoxazole) and Trimethoprim (Co-Trimoxazole) is primarily by the kidneys through both glomerular filtration and tubular secretion. Urine concentrations of both Sulfamethoxazole (Co-Trimoxazole) and Trimethoprim (Co-Trimoxazole) are considerably higher than are the concentrations in the blood. The average percentage of the dose recovered in urine from 0 to 72 hours after a single oral dose is 84.5% for total sulfonamide and 66.8% for free Trimethoprim (Co-Trimoxazole). Thirty percent of the total sulfonamide is excreted as free Sulfamethoxazole (Co-Trimoxazole), with the remaining as N4-acetylated metabolite.2 When administered together as Co-Trimoxazole, neither Sulfamethoxazole (Co-Trimoxazole) nor Trimethoprim (Co-Trimoxazole) affects the urinary excretion pattern of the other.

Both Trimethoprim (Co-Trimoxazole) and Sulfamethoxazole (Co-Trimoxazole) distribute to sputum, vaginal fluid, and middle ear fluid; Trimethoprim (Co-Trimoxazole) also distributes to bronchial secretions, and both pass the placental barrier and are excreted in human milk.

Geriatric Pharmacokinetics:

The pharmacokinetics of Sulfamethoxazole (Co-Trimoxazole) 800 mg and Trimethoprim (Co-Trimoxazole) 160 mg were studied in 6 geriatric subjects (mean age: 78.6 years) and 6 young healthy subjects (mean age: 29.3 years) using a non-US approved formulation. Pharmacokinetic values for Sulfamethoxazole (Co-Trimoxazole) in geriatric subjects were similar to those observed in young adult subjects. The mean renal clearance of Trimethoprim (Co-Trimoxazole) was significantly lower in geriatric subjects compared with young adult subjects (19 mL/h/kg vs. 55 mL/h/kg). However, after normalizing by body weight, the apparent total body clearance of Trimethoprim (Co-Trimoxazole) was an average 19% lower in geriatric subjects compared with young adult subjects.3

Microbiology:

Sulfamethoxazole (Co-Trimoxazole) inhibits bacterial synthesis of dihydrofolic acid by competing with para-aminobenzoic acid (PABA). Trimethoprim (Co-Trimoxazole) blocks the production of tetrahydrofolic acid from dihydrofolic acid by binding to and reversibly inhibiting the required enzyme, dihydrofolate reductase. Thus, Co-Trimoxazole blocks two consecutive steps in the biosynthesis of nucleic acids and proteins essential to many bacteria.

In vitro studies have shown that bacterial resistance develops more slowly with Co-Trimoxazole than with either Trimethoprim (Co-Trimoxazole) or Sulfamethoxazole (Co-Trimoxazole) alone.

In vitro serial dilution tests have shown that the spectrum of antibacterial activity of Co-Trimoxazole includes the common urinary tract pathogens with the exception of Pseudomonas aeruginosa. The following organisms are usually susceptible: Escherichia coli, Klebsiella species, Enterobacter species, Morganella morganii, Proteus mirabilis, and indole-positive Proteus species including Proteus vulgaris.

The usual spectrum of antimicrobial activity of Co-Trimoxazole includes bacterial pathogens isolated from middle ear exudate and from bronchial secretions (Haemophilus influenzae, including ampicillin-resistant strains, and Streptococcus pneumoniae), and enterotoxigenic strains of Escherichia coli (ETEC) causing bacterial gastroenteritis. Shigella flexneri and Shigella sonnei are also usually susceptible.

REPRESENTATIVE MINIMUM INHIBITORY CONCENTRATION VALUES FOR ORGANISMS SUSCEPTIBLE TO Co-Trimoxazole (MICμg/mL)

			TMP/SMX (1:19)
	TMP	SMX
Bacteria	Alone	Alone	TMP	SMX
Escherichia coli	0.05-1.5	1.0-245	0.05-0.5	0.95-9.5
Escherichia coli (enterotoxigenic strains)	0.015-0.15	0.285->950	0.005-0.15	0.095-2.85
Proteus species (indole positive)	0.5-5.0	7.35-300	0.05-1.5	0.95-28.5
			TMP/SMX (1:19)
	TMP	SMX
Bacteria	Alone	Alone	TMP	SMX
Morganella morganii	0.5-5.0	7.35-300	0.05-1.5	0.95-28.5
Proteus mirabilis	0.5-1.5	7.35-30	0.05-0.15	0.95-2.85
Klebsiella species	0.15-5.0	2.45-245	0.05-1.5	0.95-28.5
Enterobacter species	0.15-5.0	2.45-245	0.05-1.5	0.95-28.5
Haemophilus influenzae	0.15-1.5	2.85-95	0.015-0.15	0.285-2.85
			TMP/SMX (1:19)
	TMP	SMX
Bacteria	Alone	Alone	TMP	SMX
Streptococcus pneumoniae	0.15-1.5	7.35-24.5	0.05-0.15	0.95-2.85
Shigella flexneri*	<0.01-0.04	<0.16->320	<0.002-0.03	0.04-0.625
Shigella sonnei*	0.02-0.08	0.625->320	0.004-0.06	0.08-1.25

TMP=Trimethoprim (Co-Trimoxazole)

SMX=Sulfamethoxazole (Co-Trimoxazole)

*Rudoy RC, Nelson JD, Haltalin KC. Antimicrobial Agents and Chemotherapy. 1974;5:439-443.

Susceptibility Testing:

The recommended quantitative disc susceptibility method may be used for estimating the susceptibility of bacteria to Co-Trimoxazole.4,5 With this procedure, a report from the laboratory of "Susceptible to Trimethoprim (Co-Trimoxazole) and Sulfamethoxazole (Co-Trimoxazole)" indicates that the infection is likely to respond to therapy with Co-Trimoxazole. If the infection is confined to the urine, a report of "Intermediate susceptibility to Trimethoprim (Co-Trimoxazole) and Sulfamethoxazole (Co-Trimoxazole)" also indicates that the infection is likely to respond. A report of "Resistant to Trimethoprim (Co-Trimoxazole) and Sulfamethoxazole (Co-Trimoxazole)" indicates that the infection is unlikely to respond to therapy with Co-Trimoxazole.

References

1. DailyMed. "SULFAMETHOXAZOLE: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
2. DailyMed. "POLYMYXIN B SULFATE; TRIMETHOPRIM SULFATE: DailyMed provides trustworthy information about marketed drugs in the United States. DailyMed is the official provider of FDA label information (package inserts).". https://dailymed.nlm.nih.gov/dailyme... (accessed September 17, 2018).
3. NCIt. "Trimethoprim: NCI Thesaurus (NCIt) provides reference terminology for many systems. It covers vocabulary for clinical care, translational and basic research, and public information and administrative activities.". https://ncit.nci.nih.gov/ncitbrowser... (accessed September 17, 2018).

Reviews

The results of a survey conducted on ndrugs.com for Co-Trimoxazole are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Co-Trimoxazole. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.

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Information checked by Dr. Sachin Kumar, MD Pharmacology