Generic Bactrim is a drug used to treat infections of the respiratory tract, urinary tract and digestive tract. It is a complex preparation containing 2 active substances: sulfamethoxazole and trimethoprim. Both substances have an antimicrobial effect, the mechanism of which is to inhibit the activity of selected bacterial enzymes. Both co-active substances have a stronger bactericidal effect than each substance individually.

Not long ago all the infections were treated only with antibiotics. That was rather dangerous for the human health as antibiotics killed not only bacteria and infections, but also the healthy human flora. Thus, most internal organs and systems were dramatically damaged. So, the additional therapy was usually needed to recover from the treatment with antibiotics.

Nowadays pharmaceutical companies have presented antibacterial drugs which are not antibiotics and do not lead to the above-mentioned consequences. Bactrim is one of the antibacterial drugs that are popular and widely used by doctors and patients throughout the world. In this article we have collected major facts about it.

Bactrim Generic Overview

Bactrim is an antibacterial chemotherapeutic medication that contains two active ingredients: Sulfamethoxazole and Trimethoprim. The combination of the given components provides high bacterial growth inhibitory activity in relation to Gram-positive and Gram-negative organisms. They also include bacteria that are resistant to the sulfanilamides. Antibacterial effect of Bactrim is facilitated by double inhibiting action on bacteria metabolism. Sulfamethoxazole destroys biosynthesis of dihydrofolic acid and Trimethoprim blocks the following stage of metabolism which is a transfer of dihydrofolic acid into tetradihydrofolic acid necessary for the bacteria growth.

Someone considers Bactrim to be an antibiotic. However it is not true as Bactrim refers to the group of sulfanilamides. Like antibiotics Bactrim has an antibacterial action, but unlike them the medication is characterized by the chemical, rather than natural or semi-synthetic structure.

Therapeutic forms

Bactrim is produced in the form of oral suspension and pills. Oral suspension contains 200 mg of Sulfamethoxazole and 40 mg of Trimethoprim. Bactrim suspension is offered in 50 ml and 100 ml bottles, measuring spoon is included in the package.

Bactrim pill consists of 800 mg of Sulfamethoxazole and 160 mg of Trimethoprim. The pills have the market name of Bactrim Forte and are sold in 10, 20 and 50 pieces packs.

Bactrim Forte and Bactrim suspension are prescribed in similar cases (see Bactrim Uses); however Bactrim Forte is not used in children under 12 years old.

Uses of Bactrim Generic

Bactrim in both therapeutic forms is designed for the treatment of the following disorders:

  • Respiratory diseases: multiple bronchiectasis, croupous pneumonia, pneumocyctic pneumonia, bronchitis (chronic and acute), bronchial pneumonia;
  • Genitourinary diseases: urethritis, pyelitis, cystitis, pyelonephritis, lymphogranuloma venereum, epididymite, prostatitis, gonorrhea (both sexes), soft chancre, venereal granuloma;
  • ENT diseases: sinusitis, angina, otitis media, scarlet fever, laryngitis;
  • Gastrointestinal diseases: paratyphoid, typhoid, cholangitis, Salmonella, dysentery, cholera, cholecystitis, gastroenteritis caused by enterotoxic strains of Escherichia coli.
  • Skin diseases: furunculosis, pyodermatitis, acne, wound infections;
  • Other disorders: osteomyelitis (chronic and acute) and other osteoarticular infectious pathologies, acute brucellosis, malaria (Plasmodium falciparum), paracoccidioidomycosis, toxoplasmosis (as a part of the complex therapy).

Generic Bactrim

Bactrim is a medication approved by FDA. Some of its generics have the FDA approval either.

Generic Bactrim is offered in two variants of active ingredient content: single strength which is 400 mg of Sulfamethoxazole and 80 mg of Trimethoprim and double strength with 800 mg of Sulfamethoxazole and 160 mg of Trimethoprim. Bactrim is produced by several pharmaceutical companies located in the USA, Israel, and Japan.

Below there is a list of the most popular generics of Bactrim:

  • The drug is offered in the form of oral tablet. The active ingredient content makes up 400 mg of Sulfamethoxazole and 80 mg of Trimethoprim. Approved in 1982. Produced by the independent Jamaican pharmaceutical company.
  • Sulfamethoxazole and Trimethoprim. The therapeutic form is oral tablet with 400 mg of Sulfamethoxazole and 80 mg of Trimethoprim. The medication is produced both in the USA and in other countries.

All the generics of Bactrim have undergone necessary tests and analyses and are recognized to be equivalent to the branded product. However generic Bactrim is allowed to contain other inactive elements that may differ from the original medication. This thing may cause problems for patients with hypersensitivity and tendency to allergies. So, it is necessary to study the content of the medication before use.

Doses: 400/80mg, 800/160mg

Bactrim should be taken every morning and evening. Average adult dosage of Bactrim makes up 20 ml of suspension. Patients in the long-lasting therapy are recommended to take 10 ml of Bactrim in the morning and evening. In acute cases daily dosage of the medication can be increased up to 30 ml twice a day.

Bactrim can be prescribed as a one-time intake, for example, for women suffering from the uncomplicated urinary infections. In this case the one-time dosage of Bactrim can reach 40-60 ml.

Some conditions require short-term therapy which lasts within several days and up to two weeks. In other cases it is vitally important that the Bactrim dosage be calculated depending upon the patient’s weight (e.g. pneumonia treatment).

Long – term treatment with Bactrim can last from 3 months to 1.5 years if it is the case of nocardiasis. Here the daily dosage of Bactrim makes up 60-80 ml.

Pediatric doses

Pediatric dosage of Bactrim differs depending upon the age and weight of the child. New born babies (from 3 to 5 months) should be prescribed 2.5 ml of Bactrim suspension twice a day mornings and evenings. Kids from 6 months to 5 years can take 5 ml every morning and evening. 6-12 year old children are recommended to take 10 ml of Bactrim oral suspension.

Patients with heavy conditions are prescribed larger dosages, but only after the doctor’s consultation and with thorough care.


Bactrim is not used in patients who suffer from liver and kidney disorders such as severe damage of liver pulp and kidney failure. Different blood disorders including aplastic anemia, megaloblastic anemia, agranulemia, leukopenia etc. are also the reasons of refusal to administer Bactrim therapy.

Doctors do not prescribe Bactrim suspension for the new born babies (less than 3 months) and children with hyper-bilirubinaemia.

Thorough care and constant control is vitally important if the medication is taken by the patients with the deficit of folic acid, bronchial asthma, thyroid gland disorders and porphyria.

Side effects of Bactrim

If Bactrim is used as recommended it shows quite rare cases of undesired side effects. The most commonly experienced side effects involve skin rash and gastrointestinal disorders.

Other side effects occur much rarer. Nevertheless they should be described in order to prevent negative consequences.

Other skin side effects occur during the Bactrim treatment and disappear as soon as the patient stops taking the medication. The given side effects include photosensitivity, erythema multiforme development, Stevens – Johnson syndrome, toxic epidermal necrolysis (Lyell’s disease), Henoch-Schonlein purpura and DRESS syndrome.

Among other gastrointestinal side effects patients may rarely experience nausea (with or without vomiting), stomatitis, glossitis, diarrhea, hepatic necrosis, some cases of hepatitis and cholestasis as well as increased concentration of bilirubin. Rare cases of acute pancreatitis were mentioned in patients suffering from serious health disorders such as AIDS.

The following side effects occur in 0.01% cases:

  • Blood system: leukopenia, megaloblastic, hemolytic, aplastic or autoimmune anemia, agranulemia, purpura, methemoglobinemia;
  • Kidney and urinary tract: deterioration of kidney function, interstitial nephritis, increase of blood urea nitrogen and serum creatinine, crystals in urine;
  • Increased diuresis especially in patients suffering from cardiogenic edema;
  • Nervous system: neuropathy including peripheral neuritis and paresthesia, hallucinations, very rare cases of ataxia, spasmodic strictures, vertigo;
  • Respiratory system: pulmonary infiltration revealed through cough and shortbreathing;
  • Muscular system: myalgia, arthralgia.

In some cases the Bactrim therapy causes the conditions of hyperpotassemia, hyponatremia, and hypoglycemia.


The symptoms of acute Bactrim overdosing include nausea, vomiting, diarrhea and headaches, dizziness, mental and vision disorders and crystals in urine, hematuria and anuria in severe cases.

Chronic Bactrim overdosing involves thrombocytopenia, leukopenia as well as other abnormal changes in blood as a result of the lack of folic acid.

The overdosing conditions are treated depending upon the occurring symptoms. The treatment consists of several measures intended to prevent further drug input and to increase renal excretion by means of forced diuresis and hemodialysis. It is necessary to control the hematic picture and electrolytes. In case of sharp hematic picture changes or hepatitis specific treatment is prescribed.

Bactrim and alcohol

Doctors recommend that the patients should refrain from drinking alcohol during the therapy with Bactrim. Despite the fact that Bactrim does not refer to the antibiotics group the combination of Bactrim and alcohol may influence negatively the patient’s health state.

Allergic reactions to Bactrim generic

Patients with hypersensitivity to the components of Bactrim (both active and auxiliary) in the past medical history may suffer from the allergic reactions; high temperature, angioneurotic edema, allergic shock reactions and serum disease are the most common. The rare cases of allergic reactions include pulmonary infiltrates with eosinophilia. Clinically they may reveal through cough and short breathing. If such symptoms occur suddenly and show rapid development the patient should be examined and the decision to cease the Bactrim therapy should be taken.

Some patients also experienced rare cases of periarteritis nodosa and allergic myocarditis. Cases of fungal infections such as candidosis are also described during the practice of Bactrim therapy.

Bactrim and pregnancy

According to the FDA classification Bactrim has the D category for pregnancy. It means that Bactrim is not recommended for pregnant women.

Bactrim in both medical forms can be used in pregnant women only in case if the benefit for mother exceeds the threat for the baby. Bactrim is not used in women in III trimester.

Bactrim and breastfeeding

Active ingredients of Bactrim penetrate the breast milk and may cause health disorders for the new-born baby. That is why Bactrim is not recommended for the breastfeeding women.

Special notes

The duration of the treatment with Bactrim should be as short as possible in case if the medication is prescribed for the elderly patients.

In case of the long-term therapy it is necessary to constantly check the number of formed blood elements. If the number of any of them decreases the therapy should be ceased immediately. Patients suffering from heavy hematologic disorders should be prescribed Bactrim only by way of exception.

Patients suffering from kidney failure and being on the long-tern Bactrim therapy should regularly make the urine tests and control the kidney function. During the therapy such patients should be provided with the sufficient quantity of liquid in order to facilitate diuresis and to avoid crystals in urine.


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