Which medications in the drug class Penicillins, Amino are used in the treatment of Bacterial Pneumonia?

Updated: Sep 30, 2020
  • Author: Justina Gamache, MD; Chief Editor: Guy W Soo Hoo, MD, MPH  more...
  • Print
Answer

Penicillins, Amino

Amoxicillin and clavulanate (Augmentin, Augmentin XR)

Amoxicillin and clavulanate is an alternative agent for patients who are allergic or intolerant to macrolides. Amoxicillin inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins. The addition of clavulanate inhibits beta-lactamase producing bacteria.

This drug combination is usually well tolerated and provides good coverage to most infectious agents. However, it is not effective against Mycoplasma and Legionella species. The half-life of the oral dosage form is 1-1.3 hours, and it has good tissue penetration but does not enter the cerebrospinal fluid.

For children older than 3 months, base the dosing protocol on the amoxicillin content. Owing to different amoxicillin/clavulanic acid ratios in the 250-mg tablet (250/125) vs 250-mg chewable tablet (250/62.5), do not use the 250-mg tablet until the child weighs >40 kg.

Cost is a problem.

Ampicillin and sulbactam (Unasyn)

This drug is a combination of beta-lactamase inhibitor with ampicillin that is used as an alternative to amoxicillin when the patient unable to take oral medication. Ampicillin and sulbactam covers skin flora, enteric flora, and anaerobes, but it is not ideal for nosocomial pathogens. It interferes with bacterial cell wall synthesis during active replication, causing bactericidal activity against susceptible organisms.

Amoxicillin (Amoxil, Biomox, Trimox)

Amoxicillin is a penicillin derivative of ampicillin with a similar antibacterial spectrum, namely certain gram-positive and gram-negative organisms. This agent has superior bioavailability and stability to gastric acid and has a broader spectrum of activity than penicillin. However, amoxicillin is somewhat less active than penicillin against S pneumococcus. Penicillin-resistant strains are also resistant to amoxicillin, but higher doses may be effective. Amoxicillin is more effective against gram-negative organisms (eg, N meningitidis, H influenzae) than penicillin.

This agent interferes with synthesis of cell wall mucopeptides during active multiplication, resulting in bactericidal activity against susceptible bacteria.

Ampicillin (Principen)

Ampicillin is a broad-spectrum penicillin that interferes with bacterial cell wall synthesis during active replication, causing bactericidal activity against susceptible organisms. This agent is used as an alternative drug to amoxicillin when the patient is unable to take oral medication.

Previously, HACEK bacteria (Haemophilus species, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae) were uniformly susceptible to ampicillin; however, beta-lactamase–producing strains of HACEK have been identified.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!