Fentanyl (Sublimaze)

• Related chemically to meperidine.
• Approximately 80 times more potent than morphine.
• Duration of action very short (t1/2 20 min).
• Used mainly following general anesthesia.
• Neurolept analgesia: Fentanyl & Droperidol (Innovar)
• fentanyl in analgesic (2-10 µg/kg), or anaesthetic (30-100 µg/kg) doses seldom causes significant decreases in blood pressure when given alone, even in patients with poor LV function
• hypotension following fentanyl is mostly due to bradycardia and can be prevented by the use of anticholinergics, sympathomimetics or agents such as pancuronium this is more likely to occur in patients with high pre-existing sympathetic tone
• hypertension is the commonest disturbance with high dose fentanyl anaesthesia, usually accompanying intubation, sternotomy, or aortic root dissection

Lamotrigine (Lamictal): newer; broad spectrum (for most seizure types)

Mechanism: ↓ reactivation of Na channels (↑ refractory period, blocks high frequency cell firing)

Side effects: dizziness, ataxia, fatigue, nausea, no significant drug interactions

Chloramphenicol

derived from the bacterium Streptomyces venezuelae

Chloramphenicol is effective against a wide variety of microorganisms, but due to serious side-effects (e.g., damage to the bone marrow, including aplastic anemia) in humans, it is usually reserved for the treatment of serious and life-threatening infections (e.g., typhoid fever). It is used in treatment of cholera, as it destroys the

vibrios and decreases the diarrhoea. It is effective against tetracycline-resistant vibrios.It is also used in eye drops or ointment to treat bacterial conjunctivitis.

Mechanism and Resistance Chloramphenicol stops bacterial growth by binding to the bacterial ribosome (blocking peptidyl transferase) and inhibiting protein synthesis.

Chloramphenicol irreversibly binds to a receptor site on the 50S subunit of the bacterial ribosome, inhibiting peptidyl transferase. This inhibition consequently results in the prevention of amino acid transfer to growing peptide chains, ultimately leading to inhibition of protein formation.

Spectrum of activity: Broad-spectrum

Effect on bacteria: Bacteriostatic

Meperidine (Demerol)

Meperidine is a phenylpiperidine and has a number of congeners. It is mostly effective in the CNS and bowel

• Produces analgesia, sedation, euphoria and respiratory depression.
• Less potent than morphine, 80-100 mg meperidine equals 10 mg morphine.
• Shorter duration of action than morphine (2-4 hrs).
• Meperidine has greater excitatory activity than does morphine and toxicity may lead to convulsions.
• Meperidine appears to have some atropine-like activity.
• Does not constrict the pupils to the same extent as morphine.
• Does not cause as much constipation as morphine.
• Spasmogenic effect on GI and biliary tract smooth muscle is less pronounced than that produced by morphine.
• Not an effective antitussive agent.
• In contrast to morphine, meperidine increases the force of oxytocin-induced contractions of the uterus.
• Often the drug of choice during delivery due to its lack of inhibitory effect on uterine contractions and its relatively short duration of action.
• It has serotonergic activity when combined with monoamine oxidase inhibitors, which can produce serotonin toxicity (clonus, hyperreflexia, hyperthermia, and agitation)

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

Ciprofloxacin : Ciprofloxacin is bactericidal and its mode of action depends on blocking of bacterial DNA replication by binding itself to an enzyme called DNA gyrase

Ciprofloxacin is a broad-spectrum antibiotic that is active against both Gram-positive and  Gram-negative bacteria.

Enterobacteriaceae, Vibrio,  Hemophilus influenzae, Neisseria gonorrhoeae

 Neisseria menigitidis,  Moraxella catarrhalis,  Brucella, Campylobacter,

 Mycobacterium intracellulare, Legionella sp., Pseudomonas aeruginosa,

Bacillus anthracis - that causes anthrax

Weak activity against: Streptococcus pneumoniae,

No activity against:  Bacteroides,  Enterococcus faecium, Ureaplasma urealyticum  and others

It is contraindicated in children, pregnancy, and epilepsy.

Ciprofloxacin can cause photosensitivity reactions and can elevate plasma

theophylline levels to toxic values. It can also cause  constipation and sensitivity to caffeine.

Dosage in respiratory infections is 500-1500 mg a day in 2 doses.