Diuretics are chemical substances used to lower high blood pressure. They act by inhibiting the sodium-potassium-chloride ions symporter. The inhibition of the transport of these ions back into the blood leaves them in the ascending loop of henle(e part of action of diuretics). The macula densa cells of the juxtaglomerular apparatus sense the presence of these ions,especially the chloride ions and respond by producing or synthesizing more prostaglandins(simply because macula densa cells have more cox-2 receptors). Prostaglandins, therefore, cause vasodilation of the afferent arteriole thus increasing the glomerular filtration rate and hence helps in the elimination of the excess ions.In effect, prostaglandins help in the efficient working of diuretics.
however, NSAIDS block the synthesis of these prostaglandins and hence affect the efficiency of diuretics.
Asthma is a respiratory tract disease which usually affects the airways making breathing difficult. During allergic reactions, histamine is released from basophils. Histamine then binds to histaminic receptors(specifically, h6 receptors). The response to this binding is bronchoconstriction. Constricted bronchus usually affects forced expiratory volume measurements and sometimes respiratory minute rate.
NSAIDS block the cox-pathway and potentiates the lox-pathway. In the lox-pathway, LTB4 and LTD4 are produced. The latter which is produced is a potent bronchoconstrictor thus precipitating asthma. This explains why asthmatics are not to be given NSAIDS.
farewell, isn't it?
Brief introduction to anticoagulants
Anticoagulants are chemical substances(drugs), whose main mechanism of action is to prevent the coagulation(clotting) of blood in order to facilitate circulation. Anticoagulants act mainly either by inhibiting ADP receptors on platelets; inhibiting the synthesis of thromboxane A2 etc. Examples of anticoagulants include: warfarin, coumarin,clopidogrel(inihibits ADP receptors).
Since NSAIDS also act to inhibit the synthesis of thromboxane A2, the concomitant introduction of an NSAID might pose the threat of profuse bleeding. This explains why aspirin(an antiplatelet) is not given together with anticoagulants.