MASTACLOX LC

Indications

• Bacterial meningitis
• Respiratory tract infections
• Urinary tract infections
• Gastrointestinal infections
• Endocarditis prophylaxis
• Skin and soft tissue infections

Dosage

Children: Refer to BNF for Children for specific dosing guidelines based on the age and weight of the child, as well as the condition being treated.

Adults: Refer to BNF for specific dosing guidelines based on the infection being treated and patient factors such as renal function.

Mechanism of action

Ampicillin binds to penicillin-binding proteins (PBPs) located inside the bacterial cell wall, inhibiting the transpeptidation enzyme necessary for cross-linking peptidoglycan layers. This disruption in cell wall synthesis causes the bacteria to become osmotically unstable and ultimately leads to cell lysis and death.

Pharmacodynamics

Ampicillin exhibits bactericidal activity against actively dividing bacteria. Its efficacy is influenced by the time that the drug concentration remains above the minimum inhibitory concentration (MIC) of the target organisms. The spectrum of activity includes Streptococcus pneumoniae, Staphylococcus aureus (non-resistant strains), Escherichia coli, and Haemophilus influenzae.

Pharmacokinetics

Ampicillin is rapidly absorbed from the gastrointestinal tract, with peak plasma concentrations occurring within 1-2 hours after oral administration. It has a bioavailability of approximately 40-60% when taken orally. The drug is widely distributed in body tissues and fluids, including the central nervous system (CNS) during inflammation. Ampicillin is primarily excreted unchanged in the urine, with a half-life of about 1 hour in healthy adults. Dose adjustments may be necessary in patients with renal impairment.

Contra-indications

• Hypersensitivity to ampicillin or any other penicillin antibiotics
• History of severe allergic reactions to beta-lactam antibiotics

Adverse effects

• Diarrhea
• Nausea
• Vomiting
• Rash
• Allergic reactions including anaphylaxis
• Superinfection due to resistant organisms

Interactions

• Probenecid may decrease renal excretion of ampicillin, increasing its plasma concentration
• Ampicillin may reduce the effectiveness of oral contraceptives
• Concurrent use with other antibiotics may lead to antagonism

Precautions

• Use with caution in patients with a history of gastrointestinal disease, particularly colitis
• Monitor for signs of an allergic reaction, especially in patients with a history of allergies
• Renal impairment may require dosage adjustment

Pregnancy

Ampicillin is classified as pregnancy category B. It is generally considered safe for use during pregnancy when the benefits outweigh the risks.

Breast-feeding

Ampicillin is excreted in breast milk. While it is generally considered safe, monitoring the infant for potential effects is advisable.

Storage

Store in a cool, dry place away from light. Reconstituted solutions should be refrigerated and used within a specified timeframe as per manufacturer guidelines.

Formulations

• Capsules
• Tablets
• Oral suspension
• Injectable solution

Indications

• Skin and soft tissue infections caused by susceptible Staphylococcus species
• Bone and joint infections (e.g., osteomyelitis) due to Staphylococcus
• Endocarditis prophylaxis in patients with penicillin-sensitive organisms
• Respiratory tract infections caused by susceptible organisms

Dosage

Children: For children, the dosage of cl

Adults: The usual adult dose for cloxacillin is 250 mg to 500 mg every 6 hours, depending on the severity and type of infection. Higher doses may be required for more severe infections.

Mechanism of action

Cloxacillin exerts its antibacterial effects by binding to specific penicillin-binding proteins (PBPs) located within the bacterial cell wall. This binding inhibits the third and final stage of bacterial cell wall synthesis, leading to cell lysis mediated by bacterial autolytic enzymes such as autolysins. Cloxacillin is particularly effective against strains that produce penicillinase, thus broadening its spectrum of activity compared to penicillin.

Pharmacodynamics

As a semisynthetic penicillin, cloxacillin exhibits bactericidal activity, primarily targeting Gram-positive bacteria. Its action is contingent upon the bacteria being in a multiplying state since penicillins do not affect existing cell walls. Cloxacillin's effectiveness is enhanced against beta-lactamase producing strains, allowing for successful treatment of infections that would otherwise be resistant to standard penicillin.

Pharmacokinetics

Cloxacillin is well absorbed from the gastrointestinal tract, with peak plasma concentrations occurring approximately 1 to 2 hours after oral administration. It has a volume of distribution that indicates good tissue penetration, and it is metabolized in the liver. The elimination half-life is approximately 0.5 to 1 hour, with renal excretion being the primary route of elimination for the unchanged drug.

Contra-indications

• History of hypersensitivity to cloxacillin or any other penicillin antibiotics
• Severe renal impairment
• History of allergic reactions to beta-lactam antibiotics

Adverse effects

• Allergic reactions (rash, urticaria, anaphylaxis)
• Gastrointestinal disturbances (nausea, vomiting, diarrhea)
• Hepatic dysfunction (elevated liver enzymes)
• Renal impairment (nephrotoxicity)
• Hematological reactions (eosinophilia, thrombocytopenia)

Interactions

• Probenecid may increase serum levels of cloxacillin
• Anticoagulants (may increase effect)
• Other antibiotics (may have antagonistic effects)

Precautions

• Use with caution in patients with renal impairment
• Monitor for signs of allergic reactions
• Caution in patients with a history of gastrointestinal disease, particularly colitis

Pregnancy

Cloxacillin is generally considered safe to use during pregnancy, but it should only be used when clearly needed.

Breast-feeding

Cloxacillin is excreted in breast milk; caution is advised when administering to nursing mothers.

Storage

Store in a cool, dry place away from light. Once reconstituted, it should be stored in the refrigerator and used within a specified time frame as per manufacturer instructions.

Formulations

• Capsules
• Injection (vial for intravenous use)
• Oral suspension

Mechanism of action

By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, cloxacillin inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins; it is possible that cloxacillin interferes with an autolysin inhibitor. ...ITS ANTIBACTERIAL SPECTRUM AGAINST GRAM-POSITIVE BACTERIA IS LIKE THAT OF PENICILLIN EXCEPT IT IS BROADER BY MARGIN OF THOSE STRAINS OR SPECIES THAT PRODUCE PENICILLINASE. ...IT IS LESS ACTIVE THAN PENICILLIN G AGAINST NON-PENICILLINASE-PRODUCING BACTERIA, ESPECIALLY STREPTOCOCCI. /CLOXACILLIN MONOHYDRATE/ SINCE PENICILLIN HAS NO EFFECT ON EXISTING CELL WALLS, BACTERIA MUST BE MULTIPLYING FOR BACTERIAL ACTION OF PENICILLIN TO BE MANIFEST. /PENICILLINS/ 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/ Bactericidal; inhibit bacterial cell wall synthesis. Action is dependent on the ability of penicillins to reach and bind penicillin-binding proteins (PBPs) located on the inner membrane of the bacterial cell wall. Penicillin-binding proteins (which include transpeptidases, carboxypeptidases, and endopeptidases) are enzymes that are involved in the terminal stages of assembling the bacterial cell wall and in reshaping the cell wall during growth and division. Penicillins bind to, and inactivate, penicillin-binding proteins, resulting in the weakening of the bacterial cell wall and lysis. /Penicillins/ TOLERANCE DEVELOPED TO MULTIPLE DOSING. /PENICILLINS/

Pharmacodynamics

Cloxacillin is a semisynthetic antibiotic in the same class as penicillin. Cloxacillin is for use against staphylococci that produce beta-lactamase.