NEET MDS Lessons
Pharmacology
Factors affecting onset and duration of action of local anesthetics
pH of tissue
pKa of drug
Time of diffusion from needle tip to nerve
Time of diffusion away from nerve
Nerve morphology
Concentration of drug
Lipid solubility of drug
Cephalosporins
Produced semisynthetically by chemical attachment of side chains to 7-aminocephalosporanic acid. Same mode of action , same resistance mech.
But tend to be more resistant than penicillins to certain beta –lactamases .
GENERATION BASED ON :
-- BACTERIAL SUSCEPTIBILITY PATTERNS
-- RESISTANCE TO BETA –LACTAMASES
--NOT EFFECTIVE AGAINST -MRSA , L. MONOCYTOGENES , C. DIFFICLE , ENTEROCOCCI
First Generation
Parentral
- CEPHALOTHIN
- CEFAZOLIN
Oral
- CEPHALEXIN
- CEPHRADINE
- CEFADROXIL
Second Generation
Parentral
CEFUROXIME
CEFOXITIN
Oral
CEFACLOR
CEFUROXIME AXETIL
Third Generation
Parentral
CEFOTAXIME
CEFTIZOXIME
CEFTRIAXONE
CEFTAZIDIME
CEFOPERAZONE
Oral
CEFIXIME
CEFPODOXIME
CEFDINIR
CEFTIBUTEN
Fourth Generation
Parentral
CEFEPIME
CEFPIROME
Carbamazepine (Tegretol): most common; for generalized tonic-clonic and all partial seizures; especially active in temporal lobe epilepsies
Mechanism: ↓ reactivation of Na channels (↑ refractory period, blocks high frequency cell firing, ↓ seizure spread)
Side effects: induces hepatic microsomal enzymes (can enhance metabolism of other drugs)
Procaine penicillin Procaine penicillin is a combination of benzylpenicillin with the local anaesthetic agent procaine. This combination is aimed at reducing the pain and discomfort associated with a large intramuscular injection of penicillin.
Indications
respiratory tract infections where compliance with oral treatment is unlikely ,syphilis, cellulitis
Azithromycin
Azithromycin is the first macrolide antibiotic belonging to the azalide group. Azithromycin is derived from erythromycin by adding a nitrogen atom into the lactone ring of erythromycin A, thus making lactone ring 15-membered.
Azithromycin has similar antimicrobial spectrum as erythromycin, but is more effective against certain gram-negative bacteria, particularly Hemophilus influenzae.
azithromycin is acid-stable and can therefore be taken orally without being protected from gastric acids.
Main elimination route is through excretion in to the biliary fluid, and some can also be eliminated through urinary excretion
Balanced Anesthesia
A barbiturate, narcotic analgesic agent, neuromuscular blocking agent, nitrous oxide and one of the more potent inhalation anesthetic.
Classification
I) Esters
1. Formed from an aromatic acid and an amino alcohol.
2. Examples of ester type local anesthetics:
Procaine
Chloroprocaine
Tetracaine
Cocaine
Benzocaine- topical applications only
2) Amides
1. Formed from an aromatic amine and an amino acid.
2. Examples of amide type local anesthetics:
Articaine
Mepivacaine
Bupivacaine
Prilocaine
Etidocaine
Ropivacaine
Lidocaine