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MindMap Gallery Pharmacology - drugs acting on the blood and hematopoietic system, histamine receptor antagonists
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Pharmacology - drugs acting on the blood and hematopoietic system, histamine receptor antagonists
This is a mind map about pharmacology - drugs that act on the blood and hematopoietic system, histamine receptor antagonists. I hope it will be helpful to you! Interested friends, please pay attention to the collection.
Edited at 2023-11-05 10:05:37
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Pharmacology - drugs acting on the blood and hematopoietic system, histamine receptor antagonists
- bacteria
This is a mind map about bacteria, and its main contents include: overview, morphology, types, structure, reproduction, distribution, application, and expansion. The summary is comprehensive and meticulous, suitable as review materials.
- Plant asexual reproduction
This is a mind map about plant asexual reproduction, and its main contents include: concept, spore reproduction, vegetative reproduction, tissue culture, and buds. The summary is comprehensive and meticulous, suitable as review materials.
- Reproductive development of animals
This is a mind map about the reproductive development of animals, and its main contents include: insects, frogs, birds, sexual reproduction, and asexual reproduction. The summary is comprehensive and meticulous, suitable as review materials.
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029Drugs acting on blood and hematopoietic system
Thrombosis - antithrombotic drugs (anticoagulants, antiplatelet drugs, fibrinolytic drugs) Bleeding – hemostatic drugs (coagulant drugs) Hypovolemia—volume-expanding drugs (dextran) Anemia - anti-anemia drugs (iron, folic acid, vitamin B12)
anticoagulants
By affecting coagulation factors and preventing the blood coagulation process, it is mainly used clinically for the prevention and treatment of thromboembolic diseases, preventing thrombosis and preventing the expansion of formed thrombi.
heparin
Extracted from pig intestinal mucosa and cow lungs Heparin is a sulfated glycosaminoglycan Has a large negative charge, which is related to anticoagulant effects The average molecular weight is about 12kDa, and the amount of low molecular weight heparin is 6.5kDa. Not absorbed orally, often administered intravenously
Features: Rapid and powerful, anticoagulant effect both inside and outside the body
Pharmacological effects
The anticoagulant effect of heparin mainly depends on antithrombin III (AT-III), which releases anti-platelet aggregation Antiprothrombin III is a protease inhibitor that binds to coagulation factors IIa (thrombin), IXa, Xa, XIa, and XIIa to inactivate them and exert an anticoagulant effect. Heparin can speed up this reaction by more than a thousand times Heparin Antithrombin III → inactivates coagulation factors IIa, IXa, Xa, XIa, XIIa
Reduce blood lipids, anti-inflammatory effect, reduce blood viscosity
Clinical application
Thromboembolic diseases: prevention and treatment of the formation and expansion of thrombus (venous thrombosis, pulmonary embolism, arterial embolism, myocardial infarction, cerebral infarction)
Disseminated intravascular coagulation DIC: early application to prevent secondary bleeding caused by consumption of fibrin and coagulation factors
Extracorporeal anticoagulation: cardiac catheterization, extracorporeal circulation, hemodialysis
Adverse reactions
Bleeding: the most important, manifested by various mucosal bleeding, hemarthrosis and wound bleeding Prevention and treatment: ① Control the dose ② Monitor coagulation time or partial thromboplastin time ③ Mild overdose, just stop taking the drug ④ For severe bleeding, slowly inject protamine intravenously. Each 1.0-1.5 mg of protamine can cause 100 U of heparin to be lost. live
Thrombocytopenia: related to immune response Others: allergic reactions (asthma, urticaria, conjunctivitis, fever), long-term use - osteoporosis and fractures, pregnant women - premature birth and stillbirth
Contraindications: Heparin allergy, bleeding tendency (hemophilia, platelet insufficiency, thrombocytopenia), severe hypertension, bacterial endocarditis, hepatic and renal insufficiency, pregnant women
Low molecular weight heparin (clinically has a tendency to replace heparin)
① Small individual differences ②Laboratory monitoring of anticoagulant activity is generally not required ③Low toxicity and safe ④Long action time ⑤ Less bleeding reaction, related to inhibiting Xa activity ⑦Less caused by platelets↓
Vitamin K antagonists (oral anticoagulants)
Dicoumarol, warfarin (coumarin, most commonly used), acenocoumarol (new anticoagulant)
dicoumarol
Process in the body: absorption is slow and irregular, most of it is combined with plasma proteins, can pass through the placenta, be metabolized in the liver, and excreted by the kidneys
Pharmacological effects
Coumarins are vitamin K antagonists that inhibit vitamin K epoxy reductase, ↓ the formation of hydroquinone vitamin K, and produce anticoagulant effects. (The precursors for the liver to synthesize coagulation factors II, VII, IX, and
Clinical application
Thromboembolic disease (caused by atrial fibrillation, valvular heart disease) Advantages: effective orally, cheap, long acting time Disadvantages: slow effect, long operation time, difficult to control
Adverse reactions
It can easily lead to spontaneous bleeding and the most serious intracranial hemorrhage. Prothrombin must be monitored during use. If excessive dosage causes severe bleeding, stop taking the drug immediately and inject a large amount of vitamin K intravenously or transfuse fresh blood. Gastrointestinal reactions, granulocytes ↑ Affects fetal skeletal development, bleeding disorders
sodium citrate
Pharmacological effects: citrate ions form a soluble complex that is difficult to dissociate with ca2 in the blood, ca2 ↓, and blood coagulation is hindered
Clinical application: extracorporeal blood preservation (100ml whole blood 2.5% sodium citrate 10ml)
Adverse reactions: a large number → tetany, even cardiac insufficiency, blood pressure ↓ (calcium salt prevention and treatment)
Features: anticoagulation outside the body, no anticoagulation inside the body
antiplatelet drugs
Platelets are small pieces of biologically active cytoplasm that are shed from the cytoplasm of mature megakaryocytes in the bone marrow. Platelet functions: adhesion, aggregation, release, secretion of granule contents (ADP, 5-HT) The process of thrombus formation begins with the adhesion of platelets to the exposed collagen in the intima, so the formation of platelet adhesion is the first step in thrombosis.
Inhibits platelet arachidonic acid metabolism
Aspirin: Inhibits COX-1 (high dose), inhibits TXA2 (low dose) Prostaglandins: Inhibit TXA2
Dipyridamole—inhibits PDE, excites AC, and increases cAMP
Ticlopidine, clopidogrel – inhibit APD receptors
Abciximab – inhibits GPIIb/IIIa receptors
fibrinolytic drugs
However, plasminogen is converted into plasmin. Plasmin degrades fibrin and fibrinogen to limit the growth of thrombus and dissolve thrombus. It is also called thrombolytic drug (thrombolytic drug).
Streptokinase (thrombolytic enzyme) SK
Source - beta-hemolytic streptococci Pharmacological effects: Indirect activation of plasminogen. SO plasminogen→SK-plasminogen complex→promote plasmin in the plasminogen site and hydrolyze fibrin Clinical application - Thromboembolic, it is ineffective against long-formed and organized thrombus, the drug should be used as early as possible, and the best effect is ≤6 hours for thrombotic diseases Adverse reactions: bleeding, allergy The first dose should be large
Urokinase
Synthesized by human kidney cells and extracted from urine Pharmacological effects: Direct activation of plasminogen → plasmin → thrombolysis Clinical application: Same as SK, with obvious effect on cerebral embolism Expensive, only for people with SK allergies or drug resistance Adverse reactions: bleeding Non-antigenic, does not cause allergic reactions
Procoagulants
Prevent and treat bleeding disorders by activating certain coagulation factors or inhibiting fibrin degradation
Fibrinolysis inhibitors—aminobenzoic acid (most commonly used), tranexamic acid
Pharmacological effects
Low dose: competitively blocks the binding of plasminogen to fibrin High dose: Directly inhibits plasmin activity
Clinical application
Bleeding caused by hyperfibrinolytic system: Abnormal bleeding during surgeries on the lungs, liver, spleen, kidneys, prostate, thyroid, adrenal glands, etc. Bleeding caused by overdose of thrombolytic drugs (urokinase, streptokinase)
Adverse reactions: gastrointestinal reactions, excessive thrombosis or induction of myocardial infarction
Vitamin K
Category: Fat-soluble vitamins, requiring bile to assist in absorption (K1 exists in green plants, K2 is produced by intestinal bacteria); water-soluble vitamins, synthetic products (K3, K4) The basic structure is menaquinone
Pharmacological effects
As a coenzyme of carboxylase, it participates in the activation of coagulation factors II, VII, IX, and X. Vitamin K deficiency → Liver synthesizes coagulation factors without coagulation activity... → Prothrombin time ↑ → Coagulation disorder → Bleeding
Clinical application
Prevent and treat bleeding caused by vitamin K deficiency
Vitamin K malabsorption: obstructive jaundice, biliary fistula, chronic diarrhea Vitamin K synthesis disorder: premature infants, newborns, long-term use of broad-spectrum antibiotics
Detoxification of anticoagulant overdose: coumarins, salicylates (aspirin)
Treatment of biliary colic caused by biliary roundworms: K1K3 intramuscular injection → antispasmodic and analgesic
Adverse reactions
Low toxicity K1 intravenous injection too fast → chest tightness, sweating, facial flushing, and drop in blood pressure (intravenous injection rate ≤ 5 mg/min) Gastrointestinal effects: K3K4
anti-anemia drugs
Anemia - a condition in which the number of red blood cells and hemoglobin in the circulating blood is lower than normal Diagnostic criteria: Male - Hb＜120g/L, Female - Hb＜110g/L, Pregnant woman - Hb＜100g/L Common anemia types: ① Damage to the production site: aplastic anemia (bone marrow hematopoietic dysfunction) ②Lack of raw materials for production: microcytic hypochromic anemia (iron deficiency anemia); megaloblastic anemia (deficiency of folic acid or vitamin B12)
iron supplement
Iron is an important component of hemoglobin, myoglobin, cytochrome system, etc. Iron deficiency is common in: ① Acute and chronic blood loss ② Need > intake (pregnancy, children) ③ Gastrointestinal absorption disorder Ferrous sulfate (oral), ferric ammonium citrate (poorly absorbed), iron dextran (injection only) Adults need 1mg/d of iron, and a general diet is sufficient
internal processes
Iron absorption site: duodenum and upper jejunum Absorption of iron from food as Fe2 form Promote absorption: gastric acid, vitamin C, fructose, glutathione (reducing Fe3 to Fe2) Inhibition of absorption: Achlorhydria, high phosphorus, high calcium, tannins, tetracyclines, antacids, H2 receptor blockers, proton pump inhibitors, etc. can precipitate iron or inhibit the formation of Fe2
Pharmacological effects: Iron is an essential substance for the synthesis of heme in the mature stage of red blood cells. Iron is absorbed into the bone marrow, adsorbed on the nucleated red blood cell membrane and enters the mitochondria. It combines with protoporphyrin to form heme, which is then combined with globin to form hemoglobin. hemoglobin
Clinical application: Iron deficiency anemia caused by excessive blood loss (chronic blood loss such as menorrhagia, peptic ulcer, hemorrhoids) or increased iron demand (malnutrition, pregnancy, childhood growth period)
Adverse reactions
Gastrointestinal reactions: irritation of the gastrointestinal tract, nausea, vomiting, upper abdominal discomfort, diarrhea, should be taken after meals, constipation, melena (Fe²⁺ H2S→FeS) Acute poisoning: Children who mistakenly take more than 1g can cause necrotizing gastroenteritis, bloody ascites, shock, and dyspnea. First aid: gastric lavage with phosphate or phosphate solution, and inject deferoxamine, a specific antidote, into the stomach to bind the remaining iron
folic acid
It consists of three parts: pteridine core, p-aminobenzoic acid and glutamic acid. It is widely found in animal and plant foods.
Pharmacological effects: Folic acid is converted into tetrahydrofolate under the action of dihydrofolate reductase. Tetrahydrofolate can transfer one carbon unit and participate in various biological transformations. Folic acid deficiency → dTMP (deoxythymidylate) synthesis is blocked, DNA synthesis is blocked, protein synthesis is affected, and blood cell development is stagnant, resulting in megaloblastic anemia. Cell proliferation in other rapidly proliferating tissues (digestive tract) is inhibited, leading to gastritis, glossitis, and diarrhea.
Clinical application
① Used for megaloblastic anemia caused by various reasons. Better results when combined with vitamin B12 ② For megaloblastic anemia caused by folic acid antagonists such as methotrexate and ethylamine, because dihydrofolate reductase is inhibited, the application of folic acid is ineffective and needs to be treated with calcium leucovorin or calcium leucovorin. ③For "pernicious anemia" caused by vitamin B12 deficiency, high-dose folic acid treatment can correct the blood picture, but cannot improve neurological symptoms. Treatment should be based on vitamin B12 injections, supplemented by folic acid.
Vitamin B12
Cobalt-containing compounds, medicinal vitamin B12, are isolated from the fermentation broth of the actinomycete genus Streptomyces griseus, including cyanocobalamin and hydroxocobalamin. Vitamin B12 with coenzyme activity in the body - Methylamine, 5'-deoxyadenosylcobalamin Vitamin B12 is rich in animal organs, milk, and egg yolks, and is rarely found in plants.
internal processes
Vitamin B12 must combine with the glycoprotein secreted by the gastric parietal cells, that is, "intrinsic factor" to prevent it from being digested by gastric juice and enter the jejunum for absorption. The lack of intrinsic factor caused by gastric mucosal atrophy can affect the absorption of vitamin B12 and cause pernicious anemia.
Pharmacological effects: It is an essential component for cell division and maintaining the integrity of the myelin sheath of nervous tissue. *Involved in the synthesis of nucleic acids and proteins *Participate in the recycling of folic acid
Mainly used to treat pernicious anemia, used by injection, supplemented by folic acid Megaloblastic anemia: combined with folic acid Adjuvant treatment for neurological diseases (neuritis, neuroatrophy), liver diseases (hepatitis, cirrhosis) hyperhomocysteinemia
blood volume expansion drugs
Drugs that maintain blood colloid osmotic pressure and expand blood volume. They are mainly used for hypovolemic shock caused by massive blood loss or extensive burns.
Dextran
Glucose polymers are available in low to medium molecular weight formulations. Commonly used: dextran 70 (medium molecular weight), 40 (low molecular weight), 10 (small molecular weight)
Pharmacological effects
Expand blood volume: The intensity of the effect gradually decreases according to its molecular weight, used for hypovolemic shock Inhibits platelet and red blood cell aggregation
Clinically used to prevent disseminated intravascular coagulation, myocardial infarction, and cerebral thrombosis in the late stages of shock Osmotic diuresis to treat cerebral edema
Adverse reactions: allergic reactions, slow infusion at the beginning, close observation for 5-10 minutes, continuous or excessive bleeding. Contraindicated in patients with bleeding disorders, thrombocytopenia and heart failure
030 Histamine receptor antagonists
Histamine is produced from histidine through histidine decarboxylase. It is a type of autoactive substance that is widely distributed in the body and has a variety of physiological activities. It mainly exists in mast cells.
H1 receptor blockers are classified according to whether they have central effects
First generation (ethylamines)
Diphenhydramine, promethazine, chlorpheniramine, chlorpheniramine, phenylindamine
Second generation (non-ethylamines)
Astemizole, terfenadine, cetirizine, loratadine, avastine
Process in the body: It is easily absorbed orally, and the second generation lasts longer. The first generation can pass through the blood-brain barrier, and is metabolized by the liver and excreted by the kidneys.
Pharmacological effects
Block H1 receptor effects
Antagonizes the contraction of gastrointestinal and bronchial smooth muscles, the dilation of small blood vessels, and the increase in capillary permeability caused by histamine. If H1 receptor blockers are given first, guinea pigs can receive hundreds of times the lethal dose of histamine without dying. H1 receptors only have a partial antagonistic effect on the vasodilation and blood pressure drop caused by histamine, and H2 receptor blocking drugs need to be combined with the cardiovascular regulatory function.
central depressant effect
The first-generation drugs can pass through the blood-brain barrier, especially diphenhydramine and promethazine, which have strong sedative and hypnotic effects.
Others: Prevent dizziness and vomiting, anticholinergic effects (diphenhydramine, promethazine), treat nasal congestion (mizolastine)
Clinical application
Skin and mucosal allergic diseases: H1 receptor blockers are effective in urticaria, allergic rhinitis, skin itching and edema caused by insect bites, serum sickness, drug rash, contact dermatitis (Can combat histamine-induced bronchospasm in guinea pigs, but is ineffective in patients with bronchial asthma and ineffective in anaphylactic shock)
Treatment of skin allergies: stop contact with allergens, H1 receptor blockers are preferred, calcium gluconate is used as an auxiliary, and dexamethasone is used to relieve allergies.
Motion sickness, vomiting (diphenhydramine, promethazine, bucorizine, meclozine)
Others: Sedation, treatment of insomnia (promethazine, diphenhydramine)
Adverse reactions
The second generation has fewer side effects than the first generation
Central depression - drowsiness, dizziness, fatigue, slowness (first generation), prohibited for drivers and high-altitude workers Gastrointestinal reactions - dry mouth, anorexia, bloating, nausea, vomiting, diarrhea, constipation Others - granulocyte ↓, platelet ↓, hemolytic system reaction, long-term use of large doses or large doses in patients with cardiomyopathy can lead to severe arrhythmia (torsade de pointes).
H2 receptor blockers
Treatment of peptic ulcers, Zoei syndrome, reflux esophagitis, and other diseases involving excessive gastric acid secretion By selectively blocking H2 receptors on the gastric parietal cell membrane, it inhibits gastric acid secretion caused by histamine, and also has a certain inhibitory effect on gastric acid secretion caused by gastrin and acetylcholine.