Amoxicillin

Amoxicillin is an antibiotic from the penicillin group that is used to treat a wide range of bacterial infections. It is a semi-synthetic derivative of penicillin and has a broad antibacterial action.

Amoxicillin acts by inhibiting bacterial cell wall synthesis. It binds to proteins that bacteria use to keep their cell walls viable and multiply (penicillin binding proteins). This disruption leads to a weakening of the cell wall structure, which eventually causes lysis (destruction) of the bacteria.

Indications Amoxicillin

1. Respiratory tract infections:

   • Acute sinusitis
   • Acute bronchitis and exacerbation of chronic bronchitis
   • Pneumonia
   • Tonsillitis (inflammation of the tonsils)

2. Ear, throat and nose infections:

   • Otitis media (inflammation of the ear)
   • Pharyngitis (sore throat).

3. Urinary tract infections:

   • Cystitis (inflammation of the bladder)
   • Pyelonephritis (inflammation of the kidneys)

4. Skin and soft tissue infections:

   • Cellulite
   • Abscesses
   • Wound infections

5. Gastrointestinal infections:

   • Typhoid and paratyphoid
   • Salmonellosis infections

6. Gynecologic infections:

   • Endometritis (inflammation of the mucous membrane of the uterus)
   • Gonorrhea (when used in combination with other antibiotics)

7. Other infections:

   • Sepsis
   • Peritonitis (inflammation of the peritoneum).
   • Infections associated with surgical procedures

Release form

1. Pills

• Conventional tablets: Most often contain 250 mg or 500 mg of amoxicillin.
• Dispersible tablets: These tablets dissolve in water, which is convenient for children and adults who have difficulty swallowing.

2. Capsules

• Standard capsules: Usually contain 250 mg or 500 mg of amoxicillin and are intended for oral administration.

3. Powder for preparation of oral suspension

• Suspension: Intended mainly for children, simplifying dosage for younger age groups. The powder is diluted in water and is usually available in dosages providing 125 mg or 250 mg of amoxicillin per 5 ml of finished suspension.

4. Powder for injection

• Injection: Used for more serious infections and in conditions where oral administration is not possible. Dosages may vary according to specific needs and treatment conditions.

Pharmacodynamics

1. Mechanism of Action: Amoxicillin inhibits the synthesis of the bacterial cell wall, which leads to the death of bacteria. It binds to proteins called transpeptidases, which are involved in the formation of peptidoglycan, the main component of the bacterial cell wall. This leads to disruption of peptidoglycan synthesis and weakening of the cell wall, which ultimately leads to the death of the bacterial cell.
2. Spectrum of action: Amoxicillin is generally active against a wide range of Gram-positive bacteria, such as

Gram-positive bacteria:

• Streptococcus pneumoniae
• Streptococcus pyogenes

Gram-negative bacteria:

• Haemophilus influenzae
• Moraxella catarrhalis
• Escherichia coli
• Proteus mirabilis
• Salmonella spp.
• Shigella spp.
• Neisseria gonorrhoeae
• Neisseria meningitidis
• Helicobacter pylori (in combination with a proton pump inhibitor)
• Streptococcus agalactiae
• Enterococcus faecalis
• Staphylococcus aureus (methicillin-sensitive strains)
• Streptococcus viridans
• Corynebacterium spp.
• Listeria monocytogenes

3. Resistance: Some bacteria may be resistant to amoxicillin because of the production of beta-lactamases, an enzyme that hydrolyzes the beta-lactam ring of amoxicillin and renders it inactive. To overcome this problem, a beta-lactamase inhibitor such as clavulanic acid is added to some drugs, including amoxicillin, to protect amoxicillin from being broken down.

Pharmacokinetics

1. Absorption: Amoxicillin is usually rapidly and completely absorbed from the gastrointestinal tract after oral administration. Food does not significantly affect its absorption.
2. Distribution: Amoxicillin is distributed into tissues and body fluids. It penetrates most tissues and fluids, including the lungs, middle ear, synovial fluid, urine and bile.
3. Metabolism: Amoxicillin is practically not metabolized in the body. It acts as an antibacterial agent by inhibiting the synthesis of the bacterial cell wall.
4. Excretion: Approximately 60-70% of amoxicillin is excreted through the kidneys in unchanged form. The remainder is excreted through the intestine.
5. Half-life: The half-life of amoxicillin from the body is approximately 1 hour. This means that it can be taken several times a day, taking this period into account.

Dosing and administration

Method of application

Amoxicillin can be taken independently of meals, but taking it with food may reduce the risk of stomach irritation. It is important to take amoxicillin regularly, at regular intervals, to maintain a constant level of the medicine in the blood.

• Tablets and capsules should be swallowed whole with water.
• Dispersible tablets should be dissolved in a glass of water before use.
• Thesuspension must be shaken thoroughly before measuring the dose. Use a special measuring spoon or cup for accurate dosing.

Dosage

The dosage of amoxicillin depends on the type and severity of the infection, as well as the patient's age and renal function.

For adults

• Common infections:

  • 250-500 mg every 8 hours or
  • 500-875 mg every 12 hours

• More serious infections:

  • May be increased to 1000 mg every 8 hours.

• Gonorrhea:

  • A single dose of 3 g.

For children

• For children under 3 years of age (suspension only):

  • 20-40 mg of amoxicillin per kg of body weight per day, divided into 3 doses.

• For children over 3 years old:

  • The dosage is similar to adults, but the total amount should not exceed 500 mg at a time.

Duration of treatment

The duration of treatment is usually 7-14 days, depending on the infection. However, for some types of infections, such as streptococcal throat infections, at least 10 days is recommended to prevent the development of rheumatic fever.

Special Instructions

• It is important to complete the full course of antibiotic, even if symptoms have improved, to avoid the development of bacterial resistance.
• Amoxicillin may interact with other medicines, so it is important to tell your doctor about any medicines you are taking.
• If an allergic reaction such as rash, itching, swelling of the face, or difficulty breathing occurs, you should stop taking amoxicillin immediately and seek medical attention.

Use Amoxicillin during pregnancy

Amoxicillin is generally considered one of the safest antibiotics to use during pregnancy. However, the use of any medication during pregnancy should only be done under the supervision of a doctor. Before starting to take amoxicillin during pregnancy, be sure to consult your doctor or obstetrician-gynecologist.

Your doctor should evaluate the benefits of the antibiotic for the mother and the potential risks for the baby. It is also important to consider your current health status, stage of pregnancy, and other factors. In some cases, alternative treatments or other antibiotics may be preferred.

Contraindications

1. Hypersensitivity: People with known hypersensitivity to amoxicillin, other penicillins, or other beta-lactam antibiotics should avoid using this drug.
2. Mononucleosis-type infections: The use of amoxicillin is not recommended in infections accompanied by mononucleosis syndrome due to the risk of urticaria.
3. Serious hepatic impairment: Patients with serious hepatic impairment should take amoxicillin with caution or avoid its use.
4. Allergy: Patients with a history of allergic reactions to other beta-lactam antibiotics (e.g., cephalosporins or carbapenems) may be at increased risk of allergic reactions to amoxicillin.
5. Children and adolescents: The use of amoxicillin in children and adolescents requires special attention and supervision by a physician, especially with regard to dosage.
6. Pregnancy and breastfeeding: Amoxicillin use during pregnancy and breastfeeding may be authorized only in case of extreme necessity and under medical supervision.
7. Diarrhea and superinfections: Use of antibiotics, including amoxicillin, may cause diarrhea and increase the risk of superinfections.
8. Prolonged use: Prolonged use of amoxicillin may lead to the development of resistance of microorganisms, therefore the drug should be used with caution and only when prescribed by a physician.

Side effects Amoxicillin

1. Digestive disorders: For example, diarrhea, nausea, vomiting, abdominal pain, dyspepsia and dysbiosis.
2. Allergic reactions: Skin manifestations such as urticaria, pruritus, skin rash, angioedema, anapylaxis may occur.
3. Effect on hematopoiesis: Blood formation disorders such as anemia, leukopenia, thrombocytopenia may be observed.
4. Effects on the liver: Changes in liver function parameters may occur, including an increase in liver enzyme activity.
5. Nervous system: Headache, dizziness, drowsiness, anxiety and sleep disorders may occur.
6. Allergic angiitis: This is a rare but serious complication characterized by inflammation of blood vessels and damage to internal organs.
7. Increased sensitivity to sunlight: Some patients may experience increased sensitivity to sunlight, which can lead to sunburn or solar dermatitis.
8. Changes in the composition of intestinal microflora: The use of amoxicillin can lead to dysbacteriosis and the development of superinfection.

Overdose

1. Gastrointestinal disorders: Abrupt increase in side effects characteristic of amoxicillin, such as nausea, vomiting, diarrhea and dyspepsia.
2. Allergic reactions: Possible development of allergic reactions such as urticaria, itching, facial edema, difficulty breathing and anaphylactic shock.
3. Liver and kidney disorders: Toxic effect on the liver and kidneys, which may manifest as an increase in the level of hepatic enzymes in the blood and signs of renal failure.
4. Neurological symptoms: Neurotoxic symptoms such as headache, dizziness, impaired consciousness and seizures.

Interactions with other drugs

1. Probenecid: Probenecid may slow the excretion of amoxicillin, which may lead to an increase in its level in the blood and increase its duration of action.
2. Antibiotics: Combining amoxicillin with other antibiotics such as tetracyclines or macrolides may reduce the effectiveness of both drugs.
3. Drugs affecting the digestive tract: Antacids, drugs containing iron, or drugs that slow intestinal peristalsis may reduce the absorption of amoxicillin, which may lead to a decrease in its effectiveness.
4. Anticoagulants: Amoxicillin may increase the effect of anticoagulants such as warfarin, which may lead to increased clotting time and increased risk of bleeding.
5. Methotrexate: Amoxicillin may increase the toxicity of methotrexate, especially at high doses, by increasing its blood levels and exacerbating its side effects.