Cloned from: Pharmacology II

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Mechanism of Action: Ondansetron
Ondansetron is a selective serotonin 5-HT3 receptor antagonist. The serotonin 5-HT3 receptors are located on the nerve terminals of the vagus in the periphery and centrally in the chemoreceptor trigger zone of the area postrema. It is thought that chemotherapeutic agents produce nausea and vomiting by releasing serotonin from the enterochromaffin cells of the small intestine, and that the released serotonin then activates 5-HT3 receptors located on vagal efferents to initiate the vomiting reflex. Therefore Ondansetron works by blocking the reception of serotonin at these 5-HT3 receptors.
Mechanism of Action: Metoclopramide
Metoclopramide inhibits gastric smooth muscle relaxation produced by dopamine, therefore increasing cholinergic response of the gastrointestinal smooth muscle. It accelerates intestinal transit and gastric emptying by preventing relaxation of gastric body and increasing the phasic activity of antrum. Simultaneously, this action is accompanied by relaxation of the upper small intestine, resulting in an improved coordination between the body and antrum of the stomach and the upper small intestine. Metoclopramide also decreases reflux into the esophagus by increasing the resting pressure of the lower esophageal sphincter and improves acid clearance from the esophagus by increasing amplitude of esophageal peristaltic contractions. Metoclopramide's dopamine antagonist action raises the threshold of activity in the chemoreceptor trigger zone and decreases the input from afferent visceral nerves. Studies have also shown that high doses of metoclopramide can antagonize 5-hydroxytryptamine (5-HT) receptors in the peripheral nervous system in animals.
Mechanism of Action: Dexamethasone
Dexamethasone is a glucocorticoid agonist. Unbound dexamethasone crosses cell membranes and binds with high affinity to specific cytoplasmic receptors. This results in a modification of transcription and, hence, protein synthesis in order to achieve inhibition of leukocyte infiltration at the site of inflammation, interference in the function of mediators of inflammatory response, suppression of humoral immune responses, and reduction in edema or scar tissue. The antiinflammatory actions of dexamethasone are thought to involve phospholipase A2 inhibitory proteins, lipocortins, which control the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes.
Mechanism of Action: Glycopyrrolate
Glycopyrrolate binds to the muscarinic acetylcholine receptor. Like other anticholinergic (antimuscarinic) agents, inhibits the action of acetylcholine on structures innervated by postganglionic cholinergic nerves and on smooth muscles that respond to acetylcholine but lack cholinergic innervation. These peripheral cholinergic receptors are present in the autonomic effector cells of smooth muscle, cardiac muscle, the sinoatrial node, the atrioventricular node, exocrine glands and, to a limited degree, in the autonomic ganglia. Thus, it diminishes the volume and free acidity of gastric secretions and controls excessive pharyngeal, tracheal, and bronchial secretions.
Mechanism of Action: Atropine
Generally, atropine lowers the "rest and digest" activity of all muscles and glands regulated by the parasympathetic nervous system. This occurs because atropine is a competitive inhibitor of the muscarinic acetylcholine receptors (acetylcholine is the neurotransmitter used by the parasympathetic nervous system).
Mechanism of Action: Neostigmine
Neostigmine is a parasympathomimetic, specifically, a reversible cholinesterase inhibitor. By interfering with the breakdown of acetylcholine, neostigmine indirectly stimulates both nicotinic and muscarinic receptors. It does not cross the blood-brain barrier.
Mechanism of Action: Lidocaine
Lidocaine stabilizes the neuronal membrane by inhibiting the ionic fluxes required for the initiation and conduction of impulses thereby effecting local anesthetic action.
Mechanism of Action: Vecuronium
Vecuronium is a bisquaternary nitrogen compound that acts by competitively binding to nicotinic cholinergic receptors. The binding of vecuronium decreases the opportunity for acetylcholine to bind to the nicotinic receptor at the postjunctional membrane of the myoneural junction. As a result, depolarization is prevented, calcium ions are not released and muscle contraction does not occur.
Mechanism of Action: Heparin
The mechanism of action of heparin is antithrombin-dependent. It acts mainly by accelerating the rate of the neutralization of certain activated coagulation factors by antithrombin, but other mechanisms may also be involved. The antithrombotic effect of heparin is well correlated to the inhibition of factor Xa. Heparin interacts with antithrombin III, prothrombin and factor X.
Mechanism of Action: Phenylephrine
Phenylephrine produces its ophthalmic and systemic actions by acting on alpha 1 adrenergic receptors in the pupillary dilator muscle and the vascular smooth musle, resulting in contraction of the dilator muscle and contraction of the smooth muscle in the arterioles of the conjunctiva and peripheral vasoconstriction. Phenylephrine decreases nasal congestion by acting on alpha 1 adrenergic receptors in the arterioles of the nasal mucosa to produce constriction.
Mechanism of Action: Naloxone
While the mechanism of action of naloxone is not fully understood, the preponderance of evidence suggests that naloxone antagonizes the opioid effects by competing for the same receptor sites, especially the opioid mu receptor. Recently, naloxone has been shown to bind all three opioid receptors (mu, kappa and gamma) but the strongest binding is to the mu receptor.
Mechanism of Action: Furosemide
Furosemide, by inhibiting the reabsorption of sodium and chloride in the ascending limb of the loop of Henle, increases the urinary excretion of sodium, chloride, and water. Furosemide also increases the excretion of potassium, hydrogen, calcium, magnesium, ammonium, and phosphate and, as it inhibits carbonic anhydrase, bicarbonate.
Mechanism of Action: Labetalol
Labetalol has two asymmetric centers and therefore, exists as a molecular complex of two diastereoisomeric pairs. Dilevalol, the R,R' stereoisomer, makes up 25% of racemic labetalol. Labetalol HCl combines both selective, competitive, alpha-1-adrenergic blocking and nonselective, competitive, beta-adrenergic blocking activity in a single substance. In man, the ratios of alpha- to beta- blockade have been estimated to be approximately 1:3 and 1:7 following oral and intravenous (IV) administration, respectively. Beta-2-agonist activity has been demonstrated in animals with minimal beta-1-agonist (ISA) activity detected. In animals, at doses greater than those required for alpha- or beta- adrenergic blockade, a membrane stabilizing effect has been demonstrated.
Mechanism of Action: Epinephrine
Epinephrine works via the stimulation of alpha and beta-1 adrenergic receptors, and a moderate activity at beta-2 adrenergic receptors.
Mechanism of Action: Cefazolin
In vitro tests demonstrate that the bactericidal action of cephalosporins results from inhibition of cell wall synthesis. By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, it inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins.
Mechanism of Action: Metoprolol
Like betaxolol and atenolol, metoprolol competes with adrenergic neurotransmitters such as catecholamines for binding at beta(1)-adrenergic receptors in the heart and vascular smooth muscle. Beta(1)-receptor blockade results in a decrease in heart rate, cardiac output, and blood pressure.
Mechanism of Action: Etomidate
Etomidate binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged.
Mechanism of Action: Ketorolac
Ketorolac is a nonsteroidal anti-inflammatory drug (NSAID) chemically related to indomethacin and tolmetin. Ketorolac tromethamine is a racemic mixture of [-]S- and [+]R-enantiomeric forms, with the S-form having analgesic activity. Its antiinflammatory effects are believed to be due to inhibition of both cylooxygenase-1 (COX-1) and cylooxygenase-2 (COX-2) which leads to the inhibition of prostaglandin synthesis leading to decreased formation of precursors of prostaglandins and thromboxanes from arachidonic acid. The resultant reduction in prostaglandin synthesis and activity may be at least partially responsible for many of the adverse, as well as the therapeutic, effects of these medications. Analgesia is probably produced via a peripheral action in which blockade of pain impulse generation results from decreased prostaglandin activity. However, inhibition of the synthesis or actions of other substances that sensitize pain receptors to mechanical or chemical stimulation may also contribute to the analgesic effect. In terms of the ophthalmic applications of ketorolac - ocular administration of ketorolac reduces prostaglandin E2 levels in aqueous humor, secondary to inhibition of prostaglandin biosynthesis
Mechanism of Action: Oxytocin
Binds the oxytocin receptor which leads to an increase in intracellular calcium levels.
Mechanism of Action: Salbutamol
Salbutamol is a beta(2)-adrenergic agonist and thus it stimulates beta(2)-adrenergic receptors. Binding of albuterol to beta(2)-receptors in the lungs results in relaxation of bronchial smooth muscles. It is believed that salbutamol increases cAMP production by activating adenylate cyclase, and the actions of salbutamol are mediated by cAMP. Increased intracellular cyclic AMP increases the activity of cAMP-dependent protein kinase A, which inhibits the phosphorylation of myosin and lowers intracellular calcium concentrations. A lowered intracellular calcium concentration leads to a smooth muscle relaxation. Increased intracellular cyclic AMP concentrations also cause an inhibition of the release of mediators from mast cells in the airways.
Mechanism of Action: Diphenhydramine
Diphenhydramine competes with free histamine for binding at HA-receptor sites. This antagonizes the effects of histamine on HA-receptors, leading to a reduction of the negative symptoms brought on by histamine HA-receptor binding.
Mechanism of Action: Rocuronium Bromide
Rocuronium competes with acetylcholine (ACh) molecules and binds to muscarinic acetylcholine receptors on the post-synaptic membrane of the motor endplate. It blocks the action of ACh and prevents activation of the muscle contraction process. It can also act on nicotinic presynaptic acetylcholine receptors which inhibits the release of ACh.
Mechanism of Action: Succinylcholine
The mechanism of action of Succinylcholine involves what appears to be a "persistent" depolarization of the neuromuscular junction. This depolarization is caused by Succinylcholine mimicking the effect of acetylcholine but without being rapidly hydrolysed by acetylcholinesterase. This depolarization leads to desensitization.
Mechanism of Action: Propofol
The action of propofol involves a positive modulation of the inhibitory function of the neurotransmitter gama-aminobutyric acid(GABA) through GABA-A receptors.
Mechanims of Action: Ephedrine
Ephedrine is a sympathomimetic amine - that is, its principal mechanism of action relies on its direct and indirect actions on the adrenergic receptor system, which is part of the sympathetic nervous system. Ephedrine increases post-synaptic noradrenergic receptor activity by (weakly) directly activating post-synaptic α-receptors and β-receptors, but the bulk of its effect comes from the pre-synaptic neuron being unable to distinguish between real adrenaline or noradrenaline from ephedrine. The ephedrine, mixed with noradrenaline, is transported through the noradrenaline reuptake complex and packaged (along with real noradrenaline) into vesicles that reside at the terminal button of a nerve cell. Ephedrine's action as an agonist at most major noradrenaline receptors and its ability to increase the release of both dopamine and to a lesser extent, serotonin by the same mechanism is presumed to have a major role in its mechanism of action.
Mechanism of Action: Midazolam
It is thought that the actions of benzodiazepines such as midazolam are mediated through the inhibitory neurotransmitter gamma-aminobutyric acid (GABA), which is one of the major inhibitory neurotransmitters in the brain. Benzodiazepines increase the activity of GABA, thereby producing a calming effect, relaxing skeletal muscles, and inducing sleep. Benzodiazepines act as agonists at the benzodiazepine receptors, which form a component of the benzodiazepine-GABA receptor-chloride ionophore complex. Most anxiolytics appear to act through at least one component of this complex to enhance the inhibitory action of GABA.
Mechanism of Action: Fentanyl
Opiate receptors are coupled with G-protein receptors and function as both positive and negative regulators of synaptic transmission via G-proteins that activate effector proteins. Binding of the opiate stimulates the exchange of GTP for GDP on the G-protein complex. As the effector system is adenylate cyclase and cAMP located at the inner surface of the plasma membrane, opioids decrease intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of nociceptive neurotransmitters such as substance P, GABA, dopamine, acetylcholine and noradrenaline is inhibited. Opioids also inhibit the release of vasopressin, somatostatin, insulin and glucagon. Fentanyl's analgesic activity is, most likely, due to its conversion to morphine. Opioids close N-type voltage-operated calcium channels (OP2-receptor agonist) and open calcium-dependent inwardly rectifying potassium channels (OP3 and OP1 receptor agonist). This results in hyperpolarization and reduced neuronal excitability.
Mechanism of Action: Morphine
The precise mechanism of the analgesic action of morphine is unknown. However, specific CNS opiate receptors have been identified and likely play a role in the expression of analgesic effects. The mechanism of respiratory depression involves a reduction in the responsiveness of the brain stem respiratory centers to increases in carbon dioxide tension and to electrical stimulation.
Mechanism of Action: Acetaminophen
Acetaminophen is thought to act primarily in the CNS, increasing the pain threshold by inhibiting both isoforms of cyclooxygenase, COX-1 and COX-2, enzymes involved in prostaglandin (PG) synthesis. Unlike NSAIDs, acetaminophen does not inhibit cyclooxygenase in peripheral tissues and, thus, has no peripheral anti-inflammatory affects. While aspirin acts as an irreversible inhibitor of COX and directly blocks the enzyme's active site, studies have found that acetaminophen indirectly blocks COX, and that this blockade is ineffective in the presence of peroxides. This might explain why acetaminophen is effective in the central nervous system and in endothelial cells but not in platelets and immune cells which have high levels of peroxides. Studies also report data suggesting that acetaminophen selectively blocks a variant of the COX enzyme that is different from the known variants COX-1 and COX-2. This enzyme is now referred to as COX-3. Its exact mechanism of action is still poorly understood, but future research may provide further insight into how it works.
Mechanism of Action: Hydromorphone
Hydromorphone is a narcotic analgesic; its principal therapeutic effect is relief of pain. Hydromorphone interacts predominantly with the opioid mu-receptors. These mu-binding sites are discretely distributed in the human brain, with high densities in the posterior amygdala, hypothalamus, thalamus, nucleus caudatus, putamen, and certain cortical areas. They are also found on the terminal axons of primary afferents within laminae I and II (substantia gelatinosa) of the spinal cord and in the spinal nucleus of the trigeminal nerve. In clinical settings, Hydromorphone exerts its principal pharmacological effect on the central nervous system and gastrointestinal tract. Hydromorphone also binds with kappa-receptors which are thought to mediate spinal analgesia, miosis and sedation.
Mechanism of Action: Pantoprazole
Pantoprazole is a proton pump inhibitor (PPI) that suppresses the final step in gastric acid production by forming a covalent bond to two sites of the (H+,K+ )- ATPase enzyme system at the secretory surface of the gastric parietal cell. This effect is dose- related and leads to inhibition of both basal and stimulated gastric acid secretion irrespective of the stimulus.
Mechanism of action: Oxycodone
Oxycodone acts as a weak agonist at mu, kappa, and delta opioid receptors within the central nervous system (CNS). Oxycodone primarily affects mu-type opioid receptors, which are coupled with G-protein receptors and function as modulators, both positive and negative, of synaptic transmission via G-proteins that activate effector proteins. Binding of the opiate stimulates the exchange of GTP for GDP on the G-protein complex. As the effector system is adenylate cyclase and cAMP located at the inner surface of the plasma membrane, opioids decrease intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of nociceptive neurotransmitters such as substance P, GABA, dopamine, acetylcholine, and noradrenaline is inhibited. Opioids such as oxycodone also inhibit the release of vasopressin, somatostatin, insulin, and glucagon. Opioids close N-type voltage-operated calcium channels (kappa-receptor agonist) and open calcium-dependent inwardly rectifying potassium channels (mu and delta receptor agonist). This results in hyperpolarization and reduced neuronal excitability.
Mechanism of Action: Venlafaxine
Venlafaxine and its active metabolite, O-desmethylvenlafaxine (ODV), inhibit the reuptake of both serotonin and norepinephrine with a potency greater for the 5-HT than for the NE reuptake process. Both venlafaxine and the ODV metabolite have weak inhibitory effects on the reuptake of dopamine but, unlike the tricyclics and similar to SSRIs, they are not active at histaminergic, muscarinic, or alpha(1)-adrenergic receptors.
Mechanism of Action: Lorazepam
Lorazepam binds to central benzodiazepine receptors which interact allosterically with GABA receptors. This potentiates the effects of the inhibitory neurotransmitter GABA, increasing the inhibition of the ascending reticular activating system and blocking the cortical and limbic arousal that occurs following stimulation of the reticular pathways.
Mechanism of Action: Pregabalin
Pregabalin binds with high affinity to the alpha2-delta site (an auxiliary subunit of voltage-gated calcium channels) in central nervous system tissues. Although the mechanism of action of pregabalin is unknown, results with genetically modified mice and with compounds structurally related to pregabalin (such as gabapentin) suggest that binding to the alpha2-delta subunit may be involved in pregabalinís antinociceptive and antiseizure effects in animal models. In vitro, pregabalin reduces the calcium-dependent release of several neurotransmitters, possibly by modulation of calcium channel function.
Mechanism of Action: Citalopram
The antidepressant, antiobsessive-compulsive, and antibulimic actions of Citalopram are presumed to be linked to its inhibition of CNS neuronal uptake of serotonin. Citalopram blocks the reuptake of serotonin at the serotonin reuptake pump of the neuronal membrane, enhancing the actions of serotonin on 5HT1A autoreceptors. SSRIs bind with significantly less affinity to histamine, acetylcholine, and norepinephrine receptors than tricyclic antidepressant drugs.
Mechanims of Action: Lisinopril
Lisinopril competes with angiotensin I for its binding site on the angiotensin-converting enzyme (ACE), an enzyme which converts angiotensin I to angiotensin II. As angiotensin II is a vasoconstrictor and a negative feedback mediator for renin activity, lower angiotensin II plasma levels result in decreased blood pressure and increased plasma renin activity. Baroreceptor reflex mechanisms, stimulated by the fall in blood pressure, release kininase II, an enzyme identical to ACE that degrades bradykinin, a vasodilator.
Mechanism of Action: Piroxicam
The antiinflammatory effect of Piroxicam may result from the reversible inhibition of cyclooxygenase, causing the peripheral inhibition of prostaglandin synthesis. The prostaglandins are produced by an enzyme called Cox-1. Piroxicam blocks the Cox-1 enzyme, resulting into the disruption of production of prostaglandins. Piroxicam also inhibits the migration of leukocytes into sites of inflammation and prevents the formation of thromboxane A2, an aggregating agent, by the platelets.
Mechanism of Action: Tramadol
Tramadol and its O-desmethyl metabolite (M1) are selective, weak OP3-receptor agonists. Opiate receptors are coupled with G-protein receptors and function as both positive and negative regulators of synaptic transmission via G-proteins that activate effector proteins. As the effector system is adenylate cyclase and cAMP located at the inner surface of the plasma membrane, opioids decrease intracellular cAMP by inhibiting adenylate cyclase. Subsequently, the release of nociceptive neurotransmitters such as substance P, GABA, dopamine, acetylcholine and noradrenaline is inhibited. The analgesic properties of Tramadol can be attributed to norepinephrine and serotonin reuptake blockade in the CNS, which inhibits pain transmission in the spinal cord. The (+) enantiomer has higher affinity for the OP3 receptor and preferentially inhibits serotonin uptake and enhances serotonin release. The (-) enantiomer preferentially inhibits norepinephrine reuptake by stimulating alpha(2)-adrenergic receptors.
Mechanism of Action: Diclofenac
The antiinflammatory effects of diclofenac are believed to be due to inhibition of both leukocyte migration and the enzyme cylooxygenase (COX-1 and COX-2), leading to the peripheral inhibition of prostaglandin synthesis. As prostaglandins sensitize pain receptors, inhibition of their synthesis is responsible for the analgesic effects of diclofenac. Antipyretic effects may be due to action on the hypothalamus, resulting in peripheral dilation, increased cutaneous blood flow, and subsequent heat dissipation.
Pharmacology: Dobutamine
Dobutamine is a direct-acting inotropic agent whose primary activity results from stimulation of the beta-adrenoceptors of the heart while producing comparatively mild chronotropic, hypertensive, arrhythmogenic, and vasodilative effects. Dobutamine acts primarily on beta-1 adrenergic receptors, with little effect on beta-2 or alpha receptors. It does not cause the release of endogenous norepinephrine, as does dopamine. Dobutamine is indicated when parenteral therapy is necessary for inotropic support in the short-term treatment of patients with cardiac decompensation due to depressed contractility resulting either from organic heart disease or from cardiac surgical procedures.
Mechanism of Action: Dobutamine
Dobutamine directly stimulates beta-1 receptors of the heart to increase myocardial contractility and stroke volume, resulting in increased cardiac output.
Pharmacology: Nitrogycerin
Nitroglycerin, an organic nitrate, is available in many forms as a vasodilator. Nitroglycerin is used in the treatement of angina pectoris and perioperative hypertension, to produce controlled hypotension during surgical procedures, to treat hypertensive emergencies, and to treat congestive heart failure associated with myocardial infarction.
Mechanism of Action: Nitroglycerin
Similar to other nitrites and organic nitrates, nitroglycerin is converted to nitric oxide (NO), an active intermediate compound which activates the enzyme guanylate cyclase. This stimulates the synthesis of cyclic guanosine 3',5'-monophosphate (cGMP) which then activates a series of protein kinase-dependent phosphorylations in the smooth muscle cells, eventually resulting in the dephosphorylation of the myosin light chain of the smooth muscle fiber. The subsequent release of calcium ions results in the relaxation of the smooth muscle cells and vasodilation.
Pharmacology: Phenylephrine
Phenylephrine is a powerful vasoconstrictor. It is used as a mydriatic, nasal decongestant, and cardiotonic agent. Phenylephrine is a postsynaptic alpha-receptor stimulant with little effect on the beta receptors of the heart. Parenteral administration of Phenylephrine causes a rise in systolic and diastolic pressures, cardiac output is slightly decreased and peripheral resistance is considerably increased, most vascular beds are constricted; renal, splanchnic, cutaneous, and limb blood flows are reduced but coronary blood flow is increased. Pulmonary vessels are constricted, and pulmonary arterial pressure is raised. This alpha receptor sympathetic agonist is also used locally because its vasoconstrictor and mydriatic action.
Pharmacology: Epinephrine
Epinephrine is indicated for intravenous injection in treatment of acute hypersensitivity, treatment of acute asthmatic attacks to relieve bronchospasm, and treatment and prophylaxis of cardiac arrest and attacks of transitory atrioventricular heart block with syncopal seizures (Stokes-Adams Syndrome). The actions of epinephrine resemble the effects of stimulation of adrenergic nerves. To a variable degree it acts on both alpha and beta receptor sites of sympathetic effector cells. Its most prominent actions are on the beta receptors of the heart, vascular and other smooth muscle. When given by rapid intravenous injection, it produces a rapid rise in blood pressure, mainly systolic, by (1) direct stimulation of cardiac muscle which increases the strength of ventricular contraction, (2) increasing the heart rate and (3) constriction of the arterioles in the skin, mucosa and splanchnic areas of the circulation. When given by slow intravenous injection, epinephrine usually produces only a moderate rise in systolic and a fall in diastolic pressure. Although some increase in pulse pressure occurs, there is usually no great elevation in mean blood pressure. Accordingly, the compensatory reflex mechanisms that come into play with a pronounced increase in blood pressure do not antagonize the direct cardiac actions of epinephrine as much as with catecholamines that have a predominant action on alpha receptors.
Pharmacology: Nitroprusside
Nitroprusside a powerful vasodilator relaxes the vascular smooth muscle and produce consequent dilatation of peripheral arteries and veins. Other smooth muscle (e.g., uterus, duodenum) is not affected. Sodium nitroprusside is more active on veins than on arteries.
Mechanism of Action: Nitroprusside
One molecule of sodium nitroprusside is metabolized by combination with hemoglobin to produce one molecule of cyanmethemoglobin and four CN- ions; methemoglobin, obtained from hemoglobin, can sequester cyanide as cyanmethemoglobin; thiosulfate reacts with cyanide to produce thiocyanate; thiocyanate is eliminated in the urine; cyanide not otherwise removed binds to cytochromes. Cyanide ion is normally found in serum; it is derived from dietary substrates and from tobacco smoke. Cyanide binds avidly (but reversibly) to ferric ion (Fe+++), most body stores of which are found in erythrocyte methemoglobin (metHgb) and in mitochondrial cytochromes. When CN is infused or generated within the bloodstream, essentially all of it is bound to methemoglobin until intraerythrocytic methemoglobin has been saturated.
Pharmacology: Milrinone
Milrinone, a synthetic dimethylxanthine derivative structurally related to theophylline and caffeine, is used in the treatment of peripheral vascular diseases and in the management of cerebrovascular insufficiency, sickle cell disease, and diabetic neuropathy.
Mechanism of Action: Milrinone
Milrinone inhibits erythrocyte phosphodiesterase, resulting in an increase in erythrocyte cAMP activity. Subsequently, the erythrocyte membrane becomes more resistant to deformity. Along with erythrocyte activity, Milrinone also decreases blood viscosity by reducing plasma fibrinogen concentrations and increasing fibrinolytic activity.
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