Penicillins Flashcards
What is the other name for Benzylpenicillin sodium?
Penicillin G
What is the other name for phenoxymethylpenicillin?
Penicillin V
The letter “V” looks like a phoenix! :)
What is the route of administration of benzylpenicillin sodium (Penicillin G)?
slow IV injection, IV infusion, or IM
What is the route of administration for Phenoxymethylpenicillin (Penicillin V)?
Oral
Is benzylpenicillin sodium (Penicillin G) inactivated by beta-lactamases?
Yes
What organisms does benzylpenicillin sodium (Penicillin G) have activity against? (9)
Effective against the following infections:
- Many streptococcal (including pneumococcal)
- Gonococcal
- Meningococcal
- Anthrax
- Diptheria
- Tetanus
- Gas-gangrene
- Leptospirosis
- Syphilis
Is benzylpenicillin sodium (Penicillin G) well-absorbed by the GIT?
No, inactivated by gastric acid and poorly absorbed; therefore must be given by injection
What organisms does phenoxymethylpenicillin (Penicillin V) have activity against?
Similar spectrum of activity to Penicillin G but less active; gastric acid-stable so it is suitable or oral administration
*should not be used for serious infections because absorption can be unpredictable and plasma concentrations are variable
What are the primary indications for phenoxymethylpenicillin (Penicillin V)? (5)
- RTIs in children
- Streptococcal tonsillitis
- Continuing treatment after one or more injections of benzylpenicillin sodium (Penicillin G) when clinical response has begun
- Prophylaxis against streptococcal infections following rheumatic fever
- Prophylaxis against pneumococcal infections following splenectomy or in SCA
**not suitable for serious infections due to unpredictable absorption and plasma concentration eg meningococcal or gonococcal infections
What is the route of administration of phenoxymethylpenicillin (Penicillin V)?
Oral; gastric acid-stable but unpredictable absorption and plasma concentration
Which penicillins are penicillinase-resistant?
Penicillinase-resistant penicillins (AKA “second generation penicillins”) resist hydrolysis of the beta-lactam ring by bacterial enzymes, particularly STAPH
- Flucloxacillin
- Temocillin
- Neticillin
- Naficillin
- Oxacillin
“Naf for staph”
Is benzylpenicillin active against staph?
No, most staphylococci are now resistant to benzylpenicillin because they produce penicillinases (beta-lactamases)
How is flucloxacillin administered?
Oral (acid-stable, well-absorbed by the gut) or injection
What are the indications for temocillin?
Temocillin is a beta-lactamase-resistant penicillin (second gen) with activity against gram-negatives
Should be reserved for treatment of infections caused by beta-lactamase-producing strains of gram-NEGATIVE bacteria, including those resistant to third-generation cephalosporins
**NOT active against pseudomonas or acinetobacter
Which penicillins are considered broad-spectrum?
Ampicillin and amoxicillin
(Activity against certain gram (+) and gram (-) organisms BUT is inactivated by penicillinases including those produced by staph aureus and common gram (-) bacilli eg E.coli, H.influenza)