Test-2-Penicillin

Question 1

Penicillin

Answer 1

Mech of Action:

Blocks transpeptidase cross-linking of peptidoglycan (last stage of making a cell wall, its the hooking up of the pieces, looks like D - ALANYL – D - ALANINE of the cell wall pieces). -> Bacteriacidal.

_Effective against Gram-positives. _

**NOT ACTIVE AGAINST: (“Remember the odd ball ones…”)
**PSEUDOMONAS
**KLEBSIELLA

Treatment that DOES work is ***_PIPERACILLIN (PIPRACIL®), *****TICARCILLIN _

*EXCELLENT FOR PSEUDOMONAS
**PICK UP KLEBSIELLA

Toxicity:

• In general very non-toxic
• Hypersensitivity reactions (**TREATED WITHOUT KNOWLEDGE - > become reactive to penicillin.) (immediate reaction = 3 min, accelerated = 30 min, delayed = days to weeks)
• Treatment for Hypersensitivity:

**EPINEPHRINE
*DIPHENHYDRAMINE (BENADRYL®) (PRIOR)

How to solve some of the problems with Penicillin G.

Make longer lasting:

• PROBENECID (WEAK ACID), decrease EXCRETION
• PROCAINE decrease ABSORPTION

Make Acid stable:

• Added O group to R group

Make less resistant AND to make larger spectrum

• Change R group (Methicillin)

Treatments:

• Willson’s disease: Copper in the eye. A metabolite of Penicillin (β – β – DIMETHYL CYSTEINE) takes up the copper and excretes it in the urine.

Question 2

CEPHALOSPORINS

Answer 2

**LESS SUSCEPTIBLE TO PENICILLINASE (β - LACTAMASE)

BROAD SPECTRUM:
*PROTEUS
*E. COLI
*KLEBSIELLA

EXCRETED BY KIDNEY

M. OF A. = PENICILLIN

1st Generation: SKIN & SOFT TISSUE INFECTIONS (rarely drug of choice)

**CEFAZOLIN (KEFZOL®):
E. COLI, KLEBSIELLA
**CEPHALEXIN (KEFLEX®):
*ORAL, STABLE IN ACID

2nd Generation: SINUSITIS, OTITIS, LOWER RESPIRATORY TRACT INFECTIONS

• CEFAMANDOLE: *BLEEDING PROBLEMS (GIVE VITAMIN K)

3rd Generation:

• CEFOTAXIME,CEFTIZOXIME,CEFTRIAXONE:

MORE POTENT AGAINST GRAM (-).

4th Generation:

CEFEPIME
*EXCELLENT CSF LEVELS

Question 3

CARBAPENEMS

Answer 3

IMIPENEM: Broad Spectrum (anaerobes)

• Taken with *CILASTATIN ( decrease RENAL TUBULAR DIPEPTIDASE)
• *CROSS ALLERGY WITH PENICILLIN

MEROPENEM

• *CROSS ALLERGY WITH PENICILLIN

Question 4

MONOBACTAMS

Answer 4

AZTREONAM

*Gram negative Rods ONLY

*Can use for Penicillin sensitive patient

Question 5

β – LACTAMASE INHIBITORS

Answer 5

No activity in themselves, help protect Penicillin.

CLAVULANIC ACID

SULBACTAM

TAZOBACTAM

Question 6

VANCOMYCIN

Answer 6

M. OF A. : BINDS D – ALA – D – ALA

*USE: GRAM (+) - METH RESISTANT STAPH.

*USE: CLOSTRIDIUM DIFFICILE (ORAL)

**IMPORTANT BECAUSE OF RESISTANCE

Can cause “RED MAN SYNDROME”

Resistance:

**RESISTANCE TO VANCOMYCIN – (ALTERED D – ALA – D - ALA TARGET). ALA becomes Lactate, which it can’t bind to.

Toxicities:

OTOTOXIC (RARE) (+ AG = SYNERGISTIC)
NEPHROTOXIC (UNCOMMON) (+AG = SYNERGISTIC)

Question 7

TEICOPLANIN

Answer 7

***SIMILAR TO VANCOMYCIN with less resistance.

Question 8

BACITRACIN

Answer 8

INDICATIONS – STAPH INFECTIONS (THAT DO NOT RESPOND TO PEN, METH, OXA, NAF, CLOX, DICLOX)

TOXICITIES: SERIOUS NEPHROTOXICITY / (PARENTERAL) ESP. WITH AG; VERY LITTLE IF ORAL (NOT ABSORBED FROM GUT)

NEPHROTOXIC IF ENTERS SYSTEMIC CIRCULATION (THUS, MAINLY LIMITED TO TOPICAL USE)

Question 9

POLYMYXIN B SULFATE

Answer 9

Basically a detergent

**DISRUPTS CELL MEMBRANE (CATIONIC DETERGENT)

NEPHROTOXICITY

GRAM (-) INFECTIONS

Question 10

COLISTIN SULFATE

Answer 10

*DISRUPTS CELL MEMBRANE (CATIONIC DETERGENT)

GRAM (-) BACTERIA