Forensic Medicine

Monday, August 31, 2015

Anntimicrobials

·         Extended-spectrum penicillin: certain gram-positivebacteria and gram-negative rods (Haemophilus influenzae, Escherichia coli, Listeria monocytogenes, Proteus mirabilis, Salmonella, enterococci). HELPS

CEPHALOSPORIN EXCLUSIVE:
First generation: gram-positive cocci, Proteus mirabilis, E. coli, Klebsiella pneumoniae.PEcK

Second generation: gram-positive cocci, Haemophilus influenzae, Enterobacter aerogenes, Neisseria species,Proteus mirabilis, E. coli, K. pneumoniae, Serratia marcescens.HENPEcK

Third generation: serious gram-negative infections resistant to other beta-lactams; meningitis (most penetrate the blood–brain barrier).
Examples: ceftazidime for Pseudomonas; ceftriaxone for gonorrhea.

4th Gen: have PI in name
3rd Gen: have CEF/CEFT f/by AEIOU
1st GEN: have standalone L in nale (not CEFACLOR- it does not have standalone L)
               
Acting on pseudomonAZ: cefoperAZone, ceftAZidime
This ONE having bile excretion, safe in renal failure: cefoperazONE, ceftriaxONE
C/I in renal failure: cephaLOthin, cephaLOridine
Acting on Anaerobe: cefOTetan, cefOxiTin, cefOmeTazole, cefTizOxime (i.e. having –O- & -T- excluding other mnemonics)

Cefoperazone, cefotetan, Cefmetazole: inhibit aldehyde dehydrogenase, also the ones that are associated with vitamin K–related bleeding problems


·         TETRACYCLINES:
Vibrio cholerae, Acne, Chlamydia, Ureaplasma Urealyticum, Mycoplasma pneumoniae, Borrelia burgdorferi (Lyme disease), Rickettsia, tularemia. VACUUM your Bed Room


·         Foscarnet = pyroFosphate analogue

·         “Buy AT 30, CELL at 50
30S inhibitors:
A = Aminoglycosides (streptomycin, gentamicin, tobramycin, amikacin) [bactericidal]
T = Tetracyclines [bacteriostatic]

50S inhibitors:
C = Chloramphenicol [bacteriostatic]
E = Erythromycin [bacteriostatic]
L = Lincomycin [bacteriostatic]
L = cLindamycin [bacteriostatic]


·         GET on the Metro!
Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, anaerobes (Bacteroides,Clostridium)


·         INH: Injures Neurons & Hepatocytes

·         Amphotericin “tears” holes in the fungal membrane.

·         Amantadine blocks influenza A and rubellA and causes problems with the cerebellA.

·         Shake and Bake syndrome: with AMPHOTERICIN B, rigors and fever, hypotension because of histamine release-  test dose is advisable or do pretreatment with NSAIDS, antihistamines, meperidine, adrenal steroids.
                                                 

·         Amphotericin B and fluconazole enter the CSF adequately. Ketoconazole has poor penetration.


·         Serum sickness reactions: Sulfonamides, cephalosporins (especially cefaclor), minocycline, hydantoins, and penicillins.

·         Anidulafungin (Anti Fungal) and moxifloxacin (Anti Biotic) are not effective agents for urinary tract infections.

·         AZTREONAM is the most appropriate antibiotic to prescribe for gram negative coverage in a patient who is anaphylactic to penicillin.

·         Linezolid is not a bactericidal agent; it is a static drug. Additionally, the drug requires monitoring of platelet counts due to the risk of thrombocytopenia.

·         No single agent is bactericidal against enterococci. Usually penicillin has high MICs and intrinsic resistance occurs with all cephalosporins. Therefore, combination therapy with a cell wall active agent along with an aminoglycoside is necessary.

·         Acute tubular necrosis from aminoglycoside therapy typically occur Usually after 7 to 10 days of therapy.

·         Patient with recent kidney transplant is on cyclosporine for immunosuppression. Requires antifungal agent for candidiasis → what drug would result in cyclosporine toxicity? → ketoconazole.

·         CLINDAMYCIN is not of Aminoglycoside group.
LINCOMYCIN is not of Macrolide group.
Both these are LINCOSAMIDE group. Esp for Anaerobes & GN.
VANCOMYCIN only against GPC.


·         Sulfonamide potency is decreased in case of co-administration with Local anesthetics – derivatives of paraaminobenzoic acid.

·         There are several main reasons for the greater propensity for cardiovascular and bleeding problems with ticarcillin. The drug is available as a disodium salt and we often need to administer large doses of the drug. The added sodium load can increase blood volume and blood pressure. In addition, ticarcillin seems to have antiplatelet activity. This, alone, can cause a slight increase in the risk of spontaneous or excessive bleeding, and it appears that the risks are much greater if the ticarcillin is given to a patient already taking antiplatelet drugs or drugs that impair coagulation or platelet function by other mechanisms.

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·         INH: mycolic acid synthesis inhibitor

·         Balantidiasis Rx: Tetracyclines

·         piperAChine: blocking acetylcholine transmission at the myoneural junction of helminthes
·         niclOXamide: Inhibiting oxidative phosphorylation in some species of helminthes
·         PraziCantel: Increasing cell membrane permeability for calcium, resulting in paralysis, dislodgement and death of helminthes
·         Pyrantel pamoate:  neuromuscular blocking agent that causes release of acetylcholine and inhibition of cholinesterase, persistent activation of the parasite's nicotinic receptor
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·         Atovaquone possesses a novel mode of action against Plasmodium spp., inhibiting the electron transport system at the level of the cytochrome bc1 complex. The drug is active against both the erythrocytic and the exoerythrocytic stages of Plasmodium spp.; however, because it does not eradicate hypnozoites from the liver, patients with Plasmodium vivax or Plasmodium ovale infections must be given radical prophylaxis.

·         About 3% of patients treated with abacavir have an allergic reaction to it. These reactions usually include rash and nausea and sometimes include fever. If a patient with a previous reaction to abacavir is rechallenged with the medicine, he or she can develop a much more severe life-threatening reaction with marked hypotension.

·         Ritonavir is a powerful inhibitor of the liver’s P450 system. Ritonavir is used in combination with saquinavir solely to inhibit saquinavir’s metabolism, thereby keeping serum concentrations in a therapeutic range longer. Ritonavir does have protease inhibitory activation, but in this combination it is the saquinavir that is causing the main therapeutic effect.

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