Methicillin

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Structural formula
Structure of methicillin
General
Non-proprietary name Methicillin
other names

(2 S , 5 R , 6 R ) -6 - [(2,6-Dimethoxy-benzoyl) amino] -3,3-dimethyl-7-oxo-4-thia-1-azabicyclo [3.2.0] -heptane -2-carboxylic acid

Molecular formula C 17 H 20 N 2 O 6 S
External identifiers / databases
CAS number
  • 61-32-5
  • 132-92-3 (sodium salt)
EC number 200-505-8
ECHA InfoCard 100,000,460
PubChem 6087
ChemSpider 5862
DrugBank DB01603
Wikidata Q409262
Drug information
ATC code

J01 CF03

properties
Molar mass 380.42 g mol −1
Physical state

firmly

safety instructions
Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed
GHS labeling of hazardous substances
07 - Warning

Caution

H and P phrases H: 302
P: no P-phrases
Toxicological data

2000 mg kg −1 ( LD 50 ,  rat ,  oral )

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Methicillin is an antibiotic belonging to the group of β-lactam antibiotics . It is the first so-called penicillinase - resistant penicillin with a narrow range in therapy. It was developed by Beecham (now GlaxoSmithKline ) in 1959. In contrast to benzylpenicillin (penicillin G), the β-lactam ring is sterically shielded, so that it is more difficult to split and inactivate it by penicillinases ( enzymes formed by bacteria ). Methicillin is no longer on the market. In its place, oxacillin , cloxacillin , dicloxacillin and flucloxacillin are used.

Oxacillin, Cloxacillin, Dicloxacillin and Flucloxacillin are acid-proof, so they can be administered parenterally and orally . Their potency is around one percent that of benzylpenicillin. They also induce the synthesis of β-lactamases (penicillinases).

They only work against gram-positive germs; gram-negative germs are primarily resistant . When Staphylococcus aureus is resistant to methicillin (so-called. MRSA , M ethicillin- r esistenter or multidrug-resistant S taphylococcus a ureus ) or against oxacillin ( O xacillin- r esistenter S taphylococcus a ureus shortly ORSA - the more appropriate name because oxacillin yet used) it can be assumed that the strain is also resistant to all other β-lactam antibiotics. A treatment is then usually with vancomycin , an alternative course of antibiotic sensitivity , because resistance has already occurred against vancomycin. The Reserve antibiotic of choice is therefore currently linezolid .

MRSA / ORSA are often resistant to antibiotics from other groups ( quinolone antibiotics , tetracyclines , aminoglycosides , erythromycin , sulfonamides ).

Individual evidence

  1. ↑ a b c d data sheet MRSA Selective Supplement from Sigma-Aldrich , accessed on May 13, 2017 ( PDF ).
  2. ↑ Lüllmann et al .: Pharmacology and Toxicology. 17th edition. P. 482.