Antibiotics: Right Choice for Fighting Bacterial Infeсtions Successfully

Sulfonamides

Sulfonamides are some of the oldest classes of antibacterial drugs. The mechanism of action of Sulfonamides is based on an inhibition of the growth and development of many pathogenic microorganisms.

Currently, more than 6,000 derivatives of this class of antibiotics have been discovered and studied. However, only about 20 drugs have been used in modern medicine. Due to the increased resistance of microorganisms to sulfonamides, the clinical use of these antibacterial drugs is gradually reduced.

Classification of Sulfonamides

Sulfonamides can be classified in various ways. Depending on the pharmacological activity, sulfonamides can be divided into 2 groups:

Antimicrobial Sulfonamides

have a broad-spectrum bacteriostatic activity. They are prescribed for the treatment of bacterial infections.

Non-antimicrobial Sulfonamides

have diuretic and hypoglycemic effects. They are used for the diabetes treatment.

By the time of sulfonamides circulation in the body, these antimicrobial agents are divided into the following groups:

Short-acting

  • up to 8 h

Intermediate-acting

  • 8 to 16 h

Long-acting

  • 16 to 48 h

Ultra-long-acting

  • more than 48 h

Depending on the level of bioavailability, antimicrobial sulfonamides can be classified into three main groups:

  1. poorly absorbed agents (locally acting sulfonamides);
  2. rapidly absorbed agents (sulfonamides used systemically);
  3. agents absorbed through the skin (topically acting sulfonamides).

Each of the Sulfonamides groups is used to treat certain infections of different localization.

Antimicrobial sulfonamides at the US pharmaceutical market

The most common modern sulfonamides used in the US for the treatment of microbial infections are as follows:

Intermediate-acting

  • Thermazene
  • Silvadene
  • Sildaflo

Sulfacetamide

  • Bleph
  • Cetamide
  • Klaron
  • Ocusulf
  • Sulf
  • Sulfacel
  • Sulfair
  • Sulten

Sulfisoxazole

  • Gantrisin
  • Sosol
  • Soxazole
  • Sulfalar
  • Sulsoxin

Sulfasalazine

Azulfidine

S.A.S. 500

Dapsone

Aczone

Mafenide

Sulfamylon

Sulfamethoxazole

Gantanol

Urobak

Combined drugs based on Trimethoprim and Sulfamethoxazole antibiotics have been developed to increase the antimicrobial action of sulfonamides.

These drugs have a bactericidal effect and can be used to treat infections of various localization in pediatric patients aged 2 months and older.

Combined antimicrobial agents based on sulfonamides can be bought in the United States under the trade names:

  • Bactrim
  • Cotrim
  • Sulfatrim
  • Sulmeprim
  • Septra
  • Uroplus DS

The suppliers of sulfonamides are numerous local and foreign pharmaceutical companies. Among all suppliers, the most popular are the following companies:

  • Sun Pharm
  • Allergan
  • Monarch Pharms
  • Teva
  • STI Pharma
  • Sandoz
  • Jacobus
  • Pfizer
  • Vintage Pharms
  • Watson Labs
  • Roddy’s
  • Novast Labs
  • Mylan

Indications for use

Sulfonamides, which are completely and quickly absorbed from the digestive tract, usually well penetrate into all body tissues and fluids, as well as easily cross the placenta. Antimicrobials of this group are most often used to treat bacterial and protozoal infections.

Locally acting sulfonamides are poorly absorbed from the gastrointestinal tract. Consequently, they are used to treat intestinal disease and to suppress the growth of bacterial flora of the intestine before surgery.

Topical sulfonamides are used to treat bacterial eye infection, as well as can be applied to the burned area and otic canal.

Sulfonamides are considered to be safe antimicrobials and can be used in children, adolescents and adults to treat:

Gastrointestinal tract infection

  • diverticulitis
  • traveler’s diarrhea
  • ulcerative colitis

Respiratory tract infection

  • chronic bronchitis
  • pneumocystis pneumonia
  • tonsillitis

Eye infections

  • trachoma
  • glaucoma
  • inclusion conjunctivitis
  • superficial ocular infection

Skin infections

  • acne vulgaris
  • acne rosacea
  • seborrheic dermatitis
  • thermal burn injuries

Urinary tract infections

  • pyelonephritis
  • urethritis
  • cystitis

Sulfonamides can also be used for the treatment of acute otitis media, sinusitis, shigellosis, parasitic disease as cerebral toxoplasmosis in adults and children.

Antibiotics of this group are often used as adjunctive therapy in severe ulcerative colitis and as prophylaxis against recurrences of rheumatic fever. In combination with other antimicrobial drugs, sulfonamides can be used to treat meningococcal meningitis.

Dosage forms

The US pharmacies sell various dosage forms of antibiotics of the sulfonamides class, including:

Oral:

  • tablets
  • capsules
  • suspension

Ophthalmic:

  • solution
  • ointment
  • suspension

Topical:

  • gel
  • lotion
  • cream

Injection:

  • intravenous
  • intramuscular

Dosage regimen and method of administration

The duration of a treatment course, dosage regimen of sulfonamides and dosage form are selected taking into account the infection localization, the disease severity and the patient’s age.

Since tablets and capsules of sulfonamides are poorly soluble in water, they should be taken with a full glass of water. To maintain a stable level of sulfonamides in the blood throughout the day, it is important to take therapeutic doses on time.

Typically, patients are prescribed with high doses of sulfonamides at the beginning of therapy, and then smaller maintenance doses.

In the treatment of urinary tract infections, respiratory infections, gastrointestinal tract infection, the following dosage regimens are commonly used:

Adults

  • the starting doses vary in the range of 3-4 mg per day;
  • the maintenance doses make 1 to 2 mg per day.

Children aged 6 years and older

  • the starting dose varies in the range of 40 to 60 mg per kg of body weight daily;
  • the maintenance dose makes 30 mg per kg of body weight daily.

Depending on the half-life, daily doses of sulfonamide are divided into several intakes. The interval between doses can be 4 to 6 hours. It should be noted that the risk of toxicity increases when using more than 4 mg of sulfonamide-containing drug per day.

  • 1-2 drops of the drug are instilled into the infected eye every 3 hours to treat eye infections.
  • The drug is applied to the infected area 2 to 3 times a day for the topical treatment of acne and seborrheic dermatitis.

Side effects and contraindications

The most common side effects are noted during oral administration of sulfonamides. Patients may experience such gastrointestinal adverse effects as vomiting, nausea, diarrhea, and abdominal pain.

These undesired effects usually disappear as the therapy continues and do not require the drug withdrawal or medical aid.

Sulfonamides may cause allergic skin reactions – reddish or purple spots on the skin, itching and flaking in some patients. In rare cases, few patients may develop hepatic necrosis and Stevens-Johnson syndrome.

At the first signs of hypersensitivity reactions, stop using the drug and consult your doctor.

Use of sulfonamides may increase sensitivity to sunlight and cause blood problems, such as anemia or an increase in the number of eosinophils. Therefore, patients should avoid long exposure to direct sunlight and undergo a biochemical blood test during the treatment.

Sulfonamides are contraindicated in patients suffering from:

  • impaired renal and hepatic function;
  • diseases of the hematopoietic system;
  • hypersensitivity to the ingredients of a sulfonamide-containing drug.

Drug interactions

Sulfonamides can interact with a large number of drugs. Their therapeutic effect changes and the risk of side effects increases during drug interactions.

Drugs that can interact with sulfonamides are as follows:

  • diuretics;
  • thyroid drugs;
  • anticoagulants;
  • anticancer drugs;
  • birth control pills;
  • oral hypoglycemics;
  • anti-seizure medicines.
Tetracyclines
Penicillins

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