CLAV 625 TABLETS

Indications

• Bacterial infections
• Urinary tract infections
• Sinusitis
• Uncomplicated community-acquired pneumonia
• Salmonellosis
• Oral infections
• Lyme disease (under expert supervision)
• Acute exacerbation of bronchiectasis
• Anthrax (treatment and post-exposure prophylaxis)

Dosage

Children: 1 month–11 years: 30 mg/kg 3 times a day for 21 days; children 1–4 years: 250 mg 3 times a day; children 5–11 years: 500 mg 3 times a day.

Adults: 500 mg 3 times a day; increased if necessary up to 1 g 3 times a day in severe infections.

Mechanism of action

Amoxicillin works by inhibiting bacterial cell wall synthesis, leading to cell lysis and death. It binds to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, interfering with the transpeptidation process necessary for cell wall integrity.

Pharmacodynamics

Amoxicillin exhibits bactericidal activity against susceptible bacteria. Its action is time-dependent, meaning that its effectiveness is related to the duration of time that the drug concentration remains above the minimum inhibitory concentration (MIC) for the target pathogen.

Pharmacokinetics

Amoxicillin is well absorbed from the gastrointestinal tract, with peak plasma concentrations achieved within 1-2 hours after oral administration. It is widely distributed in body tissues and fluids, and it is excreted primarily via the kidneys. The elimination half-life is approximately 1 hour, and renal impairment may necessitate dosage adjustments.

Adverse effects

• Skin rash
• Gastrointestinal disturbances (nausea, vomiting, diarrhea)
• Allergic reactions (including anaphylaxis)
• Superinfection (due to resistant organisms)

Interactions

• Allopurinol (increases risk of skin rash)

Precautions

• History of penicillin allergy
• Renal impairment (reduce dose)
• Use with caution in patients with mononucleosis

Pregnancy

Use only if clearly needed; no adequate studies in pregnant women.

Breast-feeding

Amoxicillin is excreted in breast milk; use with caution.

Storage

Store in a cool, dry place away from direct sunlight.

Formulations

• Phenoxymethylpenicillin 250mg/5ml oral solution
• Phenoxymethylpenicillin 250 mg tablets

Indications

• Bacterial infections caused by beta-lactamase producing organisms
• Respiratory tract infections
• Urinary tract infections
• Skin and soft tissue infections
• Otitis media
• Sinusitis

Dosage

Children: Refer to the BNF for Children

Adults: Refer to the BNF for specific dosing guidelines, as doses may vary based on the indication and severity of the infection.

Mechanism of action

Clavulanic acid works by binding to the active site of beta-lactamases, thereby inactivating these enzymes and preventing them from hydrolyzing beta-lactam antibiotics. This action protects antibiotics from degradation, allowing them to exert their antibacterial effects. Clavulanic acid is a competitive inhibitor of these enzymes, leading to the restoration of the efficacy of beta-lactam antibiotics against resistant strains.

Pharmacodynamics

The pharmacodynamics of clavulanic acid involves its role as a beta-lactamase inhibitor, which enhances the activity of beta-lactam antibiotics by preventing bacterial resistance. It is primarily effective against bacteria that produce beta-lactamases, thereby increasing the susceptibility of these organisms to antibiotics such as amoxicillin. The combination of clavulanic acid with amoxicillin results in a synergistic effect that is greater than the sum of their individual effects.

Pharmacokinetics

Clavulanic acid is rapidly absorbed after oral administration, with peak plasma concentrations occurring within 1 hour. It has a bioavailability of approximately 25-40%, depending on the formulation. Clavulanic acid is widely distributed in body tissues and fluids, with a volume of distribution of about 0.3 L/kg. It is metabolized in the liver and excreted primarily via the kidneys, with a half-life of approximately 1 hour. Renal impairment may affect its clearance.

Contra-indications

• Hypersensitivity to clavulanic acid or any other component of the formulation
• Severe hepatic impairment
• History of cholestatic jaundice or hepatic dysfunction associated with amoxicillin/clavulanate

Adverse effects

• Nausea
• Vomiting
• Diarrhea
• Rash
• Hepatic dysfunction
• Allergic reactions
• Superinfection due to resistant organisms
• Candidiasis

Interactions

• Probenecid may decrease the renal excretion of clavulanic acid
• Anticoagulants may have altered effects due to changes in gut flora
• Concomitant use with other antibiotics may lead to increased risk of superinfection

Precautions

• Monitor liver function tests during prolonged therapy
• Use with caution in patients with renal impairment
• Hydration is important to prevent crystalluria
• Consider the risk of Clostridium difficile-associated diarrhoea

Pregnancy

Clavulanic acid is categorized as pregnancy category B. There are no adequate and well-controlled studies in pregnant women, thus it should be used during pregnancy only if clearly needed.

Breast-feeding

Clavulanic acid is excreted in breast milk in small amounts. Caution is advised when administering to breastfeeding women, as there is a potential for adverse effects in the infant.

Storage

Store in a cool, dry place away from light. Reconstituted solutions should be stored in a refrigerator and used within the specified time frame.

Formulations

• Tablets
• Oral suspension
• Injectable solution

Indications

• Hypokalemia (low potassium levels)
• Prevention of potassium depletion
• Management of certain arrhythmias
• Electrolyte replacement therapy

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations.

Adults: Refer to the specific guidelines and BNF for appropriate dosing based on individual clinical scenarios.

Mechanism of action

Potassium ions are critical for the generation and propagation of action potentials in excitable tissues, such as nerves and muscles. The ion's movement across cell membranes is facilitated by various transport mechanisms, including the sodium-potassium pump (Na+/K+ ATPase), which maintains the electrochemical gradient essential for cellular function. Potassium also plays a role in the regulation of intracellular pH and is involved in enzymatic reactions.

Pharmacodynamics

Potassium contributes to the resting membrane potential of cells, influencing excitability and contraction in cardiac and skeletal muscles. Adequate levels of potassium are necessary to prevent arrhythmias and to support normal muscle function. Hyperkalemia (high potassium levels) can lead to cardiac arrest, while hypokalemia (low potassium levels) can cause muscle weakness, cramps, and arrhythmias.

Pharmacokinetics

Potassium is absorbed primarily in the gastrointestinal tract, with the majority of potassium reabsorbed by the kidneys. The normal serum potassium concentration is tightly regulated between 3.5 to 5.0 mmol/L. Factors affecting potassium levels include dietary intake, renal function, and hormonal influences, particularly from aldosterone. Potassium is excreted primarily through the urine, with a small amount lost in feces and sweat.

Contra-indications

• Severe renal impairment
• Hyperkalemia
• Addison's disease
• Untreated primary adrenal insufficiency
• Acute or chronic metabolic acidosis

Adverse effects

• Hyperkalemia
• Cardiac arrhythmias
• Muscle weakness
• Fatigue
• Nausea
• Vomiting
• Diarrhea
• Abdominal cramping

Interactions

• ACE inhibitors may increase potassium levels
• Potassium-sparing diuretics can lead to hyperkalemia
• Non-steroidal anti-inflammatory drugs (NSAIDs) may decrease renal excretion of potassium
• Certain antibiotics (e.g., trimethoprim) can increase potassium levels

Precautions

• Monitor serum potassium levels regularly
• Use with caution in patients with renal impairment
• Consider ECG monitoring in patients with significant electrolyte imbalances
• Adjust doses in patients taking medications that affect potassium levels

Pregnancy

Potassium is essential for normal fetal development and is generally considered safe in pregnancy, but should be used under medical supervision.

Breast-feeding

Potassium is excreted in breast milk, but the amounts are typically safe; supplementation should be guided by a healthcare professional.

Storage

Store in a cool, dry place away from direct sunlight, and keep out of reach of children.

Formulations

• Oral tablets
• Oral solutions
• Injectable forms

Mechanism of action

Amoxicillin competitively inhibits penicillin-binding protein 1 and other high molecular weight penicillin binding proteins. Penicillin bind proteins are responsible for glycosyltransferase and transpeptidase reactions that lead to cross-linking of D-alanine and D-aspartic acid in bacterial cell walls. Without the action of penicillin binding proteins, bacteria upregulate autolytic enzymes and are unable to build and repair the cell wall, leading to bacteriocidal action. The penicillins and their metabolites are potent immunogens because of their ability to combine with proteins and act as haptens for acute antibody-mediated reactions. The most frequent (about 95 percent) or "major" determinant of penicillin allergy is the penicilloyl determinant produced by opening the beta-lactam ring of the penicillin. This allows linkage of the penicillin to protein at the amide group. "Minor" determinants (less frequent) are the other metabolites formed, including native penicillin and penicilloic acids. /Penicillins/ Amoxicillin is similar to penicillin in its bactericidal action against susceptible bacteria during the stage of active multiplication. It acts through the inhibition of cell wall biosynthesis that leads to the death of the bacteria.

Pharmacodynamics

Amoxicillin competitively inhibit penicillin binding proteins, leading to upregulation of autolytic enzymes and inhibition of cell wall synthesis. Amoxicillin has a long duration of action as it is usually given twice daily. Amoxicillin has a wide therapeutic range as mild overdoses are not associated with significant toxicity. Patients should be counselled regarding the risk of anaphylaxis, _Clostridium difficile_ infections, and bacterial resistance.