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Showing posts with the label Pharmacology

Aminoglycosides - why -mycin and -micin

The aminoglycoside group includes gentamicin, amikacin, netilmicin, kanamycin, tobramycin, streptomycin, paromomycin and neomycin. These drugs have a good action against aerobic gram-negative bacteria. They are rapidly bactericidal. Bacterial killing is concentration dependent: The higher the concentration, the greater is the rate at which bacteria are killed. As noted above, some of the names end by -micin while others by -mycin. The reason behind this lies in the origin of the antibiotics. All the antibiotics ending with -mycin are either natural products or semisynthetic derivatives of compounds produced by a variety of soil actinomycetes notably Streptomyces . Those ending with -micin are derived from other actinomycetes e.g Micromonospora.

Action of sympathetic and parasympathetic system on effector organs

Heparin induced thrombocytopenia

HEPARIN-INDUCED THROMBOCYTOPENIA Drug-induced thrombocytopenia due to heparin differs from that seen with other drugs in two major ways. (1) The thrombocytopenia is not usually severe, with nadir counts rarely <20,000/L. (2) Heparin-induced thrombocytopenia (HIT) is not associated with bleeding and, in fact, markedly increases the risk of thrombosis. Pathology: HIT results from antibody formation to a complex of the platelet-specific protein platelet factor 4 (PF4) and heparin. The antiheparin/PF4 antibody can activate platelets through the FcRIIa receptor and also activate monocytes and endothelial cells. Many patients exposed to heparin develop antibodies to heparin/PF4, but do not appear to have adverse consequences. 1) A fraction of those who develop antibodies will develop HIT, and a portion of those (up to 50%) will develop thrombosis (HITT). 2) HIT can occur after exposure to low-molecular-weight heparin (LMWH) as well as unfractionated heparin (UFH), alt

Penicillin - a fortunate accident

It all started when Alexander Fleming discarded some of his culture plates that had been contaminated with mold. But fortunately, he had a second look to those cultures afterwards. He was amazed to see that in the area around the mold, the growth of bacteria was inhibited. The mold was identified as Penicillium notatum, the active inhibitor named penicillin. Above is a photo taken by Alexander Fleming in 1928.

Latin abbreviations in prescribing drugs

a.c - ante cibum i.e. before food. p.c - post cibum (after food). o.m - omni mane (every morning). o.n - omni nocte (every night). o.d - omni die (once daily). b.d - bis die (twice daily). t.i.d - ter in die ( three times daily). t.d.s - ter die sumendum (to be taken three times daily). q.d.s - quater die sumendum (to be taken four times daily). p.r.n - pro re nata (when required). stat - immediately.

Effect of alcohol on body temperature

Ingestion of alcohol makes you feel warm because it causes cutaneous vasodilation. Increased blood flow to the skin coupled with a low environmental temperature means that there is a more rapid loss of heat from the body. Furthermore, consumption of a large amount of ethanol leads to depression of the central temperature regulating mechanism. Thus drinking alcohol excessively in cold climates can lead to hypothermia and even death if appropriate measures are not taken.

Azithromycin - macrolide

Group: macrolide Antimicrobial activity: Good against Gram positive and Gram negative organisms. Slightly less active than erythromycin against staphylococci and streptococci but more active against H.influenzae. It is also highly active against chlamydia, Mycobacterium avium complex and Toxoplasma gondii. Mechanism of action: It binds to the 50s ribosome subunit and hinders the translocation of the elongated peptide chain from the acceptor site to the peptidyl site. Thus the ribosome does not move along the mRNA to expose the next codon and peptide synthesis is prematurely terminated. Pharmacokinetic properties: Acid stability and more active in alkaline medium, rapid oral absorption but better given 1 hour before meals or 2 hours after meals, marked tissue distribution especially intracellular penetration (macrophages and fibroblasts), Half life : 2-4 days, therefore can be given as once a day dosing Clinical uses: 1) Legionnaire's pneumonia - 500 mg O.D for 2 wee