II. Mechanism

  1. First Generation Antihistamine

III. Adverse Effects

  1. Sedation or Paradoxic excitability
  2. Worsens Benign Prostatic Hyperplasia
  3. Worsens Glaucoma
  4. Dizziness
  5. Respiratory depression
  6. Tachycardia
  7. Seizures
  8. Torsades de Pointes
  9. Anticholinergic Symptoms
    1. Hallucinations
    2. Blurred vision
    3. Agitation

V. Anti-pruritic Effects

  1. Suppresses itching, and reduces lesions
  2. Does not completely eradicate
  3. Hydroxyzine (Atarax) is most potent Antihistamine for Pruritus

VI. Preparations: Antihistamine

  1. See Diphenhydramine (Benadryl)
  2. Chlorpheniramine (Chlor-Trimeton)
    1. Dose: 4 mg orally every 4 to 6 hours as needed
  3. Clemastine (Tavist)
    1. Dose: 1.34 mg orally twice daily as needed
  4. Cyproheptadine (Periactin)
    1. Dose: 4 mg orally three times daily as needed
  5. Hydroxyzine (Atarax, Vistaril)
    1. Dose: 0.5 mg/kg up to 25-50 mg orally or intramuscular every 4-6 hours as needed

Images: Related links to external sites (from Google)

Cost: Medications

Cyproheptadine HCl (on 2/9/2012 at DrugStore.com)
Cyproheptadine HCl 2mg/5ml Syrup #120 for $24.38 ($0.20/unit)
Cyproheptadine HCl 4mg Tablets #30 for $13.99 ($0.47/unit)
HydrOXYzine Pamoate (on 2/9/2012 at DrugStore.com)
HydrOXYzine Pamoate 25mg Capsules #60 for $15.99 ($0.27/unit)
HydrOXYzine Pamoate 100mg Capsules #30 for $19.99 ($0.67/unit)
HydrOXYzine HCl (on 2/9/2012 at DrugStore.com)
HydrOXYzine HCl 50mg/ml Solution 1ml Vial #25 for $95.99 ($3.84/unit)
HydrOXYzine HCl 10mg Tablets #30 for $17.99 ($0.60/unit)
HydrOXYzine HCl 50mg Tablets #30 for $30.99 ($1.03/unit)
HydrOXYzine HCl 10mg/5ml Syrup #473 for $61.99 ($0.13/unit)
HydrOXYzine HCl 25mg Tablets #30 for $26.99 ($0.90/unit)
Vistaril (on 2/9/2012 at DrugStore.com)
Vistaril 25mg Capsules #30 for $60.99 ($2.03/unit)
Vistaril 50mg Capsules #30 for $70.61 ($2.35/unit)

Ontology: Chlorpheniramine (C0008281)

Definition (MSH) A histamine H1 antagonist used in allergic reactions, hay fever, rhinitis, urticaria, and asthma. It has also been used in veterinary applications. One of the most widely used of the classical antihistaminics, it generally causes less drowsiness and sedation than PROMETHAZINE.
Definition (CSP) histamine H1 antagonist used in allergic reactions, hay fever, rhinitis, urticaria, asthma and in veterinary applications; one of the most widely used of the classical antihistamines.
Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH D002744
SnomedCT 9944001, 372914003
English Chlorphenamine, Chlorpheniramine, Chlorprophenpyridamine, chlorpheniramine, 2-Pyridinepropanamine, gamma-(4-chlorophenyl)-N,N-dimethyl-, Chlorpheniramine (Allergy), chlorphenamine, chlorpheniramines (medication), chlorpheniramine (medication), chlorpheniramines, antihistamines chlorpheniramines, Chlorpheniramine [Chemical/Ingredient], CHLORPHENIRAMINE, Chlorpheniramine (product), Chlorpheniramine (substance)
Swedish Klorfeniramin
Czech chlorfeniramin
Finnish Kloorifeniramiini
Japanese クロルプロフェンピリダミン, マレイン酸クロルフェニラミン, クロルフェニラミン, クロルフェナミン
Italian Clorprofenpiridamina, Clorofenamina, Clorofeniramina
Spanish Clorfeniramina, Cloroprofenpiridamina, Clorprofenpiridamina, Clorofeniramina, clorfeniramina (producto), clorfeniramina (sustancia), clorfeniramina, Clorfenamina
Polish Chlorfeniramina, Chlorfenamina
French Chlorphénamine, Chlorphéniramine
German Chlorphenamin, Chlorpheniramin, Chlorprophenpyridamin
Portuguese Clorfenamina, Clorfeniramina, Clorprofempiridamina

Ontology: Cyproheptadine (C0010620)

Definition (NCI) A drug that is used to treat asthma, allergies, and colds, and to relieve itching caused by certain skin disorders. It has also been used to stimulate appetite and weight gain, and is being studied in the treatment of weight loss caused by cancer and its treatment. Cyproheptadine belongs to the family of drugs called antihistamines.
Definition (MSH) A serotonin antagonist and a histamine H1 blocker used as antipruritic, appetite stimulant, antiallergic, and for the post-gastrectomy dumping syndrome, etc.
Definition (CSP) serotonin antagonist and histamine H1 blocker used as an antipruritic, appetite stimulant, antiallergic, and to treat the post-gastrectomy dumping syndrome.
Definition (PDQ) The hydrochloride salt of a synthetic methyl-piperidine derivative with antihistaminic and anti-serotoninergic properties. Cyproheptadine competes with free histamine (HA) for binding at HA-receptor sites, thereby competitively antagonizing histamine stimulation of HA-receptors in the gastrointestinal tract, large blood vessels, and bronchial smooth muscle. This agent also competes with free serotonin for binding at serotonin receptor sites. Cyproheptadine exhibits anticholinergic and sedative properties and has been shown to stimulate appetite and weight gain. Check for "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=315774&idtype=1" active clinical trials or "http://www.cancer.gov/Search/ClinicalTrialsLink.aspx?id=315774&idtype=1&closed=1" closed clinical trials using this agent. ("http://nciterms.nci.nih.gov:80/NCIBrowser/ConceptReport.jsp?dictionary=NCI_Thesaurus&code=C28949" NCI Thesaurus)
Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH D003533
SnomedCT 26462003, 372683000
English Cyproheptadine, cyproheptadine, Piperidine, 4-(5H-dibenzo(a,d)cyclohepten-5-ylidene)-1-methyl-, Cyproheptadine [Chemical/Ingredient], Cyproheptadine (product), Cyproheptadine (substance), CYPROHEPTADINE
Swedish Cyproheptadin
Czech cyproheptadin
Finnish Syproheptadiini
Portuguese Ciproeptadina, Ciproheptadina, Cipro-Heptadina
Polish Cyproheptadyna
Japanese シプロヘプタジン, 塩酸シプロヘプタジン
Spanish ciproheptadina (producto), ciproheptadina (sustancia), ciproheptadina, Ciproheptadina
French Cyproheptadine
German Cyproheptadin
Italian Ciproeptadina

Ontology: Histamine H1 Antagonists (C0019592)

Definition (NCI) Any agent that binds to the histamine-1 (H-1) receptor, thereby antagonizing histamine mediated allergic reactions, such as bronchoconstriction, vasodilation and up-regulated capillary permeability.
Definition (NCI) A type of drug that blocks the action of histamines, which can cause fever, itching, sneezing, a runny nose, and watery eyes. Antihistamines are used to prevent fevers in patients receiving blood transfusions and to treat allergies, coughs, and colds.
Definition (MSH) Drugs that selectively bind to but do not activate histamine H1 receptors, thereby blocking the actions of endogenous histamine. Included here are the classical antihistaminics that antagonize or prevent the action of histamine mainly in immediate hypersensitivity. They act in the bronchi, capillaries, and some other smooth muscles, and are used to prevent or allay motion sickness, seasonal rhinitis, and allergic dermatitis and to induce somnolence. The effects of blocking central nervous system H1 receptors are not as well understood.
Concepts Pharmacologic Substance (T121)
MSH D006634
SnomedCT 349955005, 373228009
English Antihistaminics, H1, H1 Antihistaminics, H1 Receptor Blockaders, Histamine H1 Receptor Blockaders, Receptor Blockaders, H1, Histamine H1 Receptor Antagonists, Antagonists, Histamine H1, Antagonists, Histamine H1 Receptor, Blockaders, Histamine H1 Receptor, H1 Antagonists, Histamine, Histamine H1 Blockers, Antihistamine, Histamine H1 Antagonists, HISTAMINE RECEPTOR ANTAGONISTS H1, BLOCKADERS HISTAMINE H1 RECEP, ANTIHISTAMINICS H 01, H1 RECEPT BLOCK, HISTAMINE H1 ANTAG, HISTAMINE H1 RECEPT ANTAG, HISTAMINE ANTAGONISTS H 001, RECEPT BLOCK H1, HISTAMINE H1 RECEPT BLOCK, HISTAMINE RECEPTOR BLOCKADERS H1, HISTAMINE H1 BLOCK, ANTAG HISTAMINE H1 RECEPT, ANTAG HISTAMINE H1, H1 blockers, histamine H1 receptor blockaders, Histamine-1 Receptor Antagonist, H1 Receptor Inhibitor, H1 Receptor Antagonist, Histamine-1 Receptor Antagonist [EPC], antihistaminic h1, h1 antihistamine, h1 blockers, antihistamine h1, antihistamines h1, h1 blocker, antihistamine, H1 antihistamine, H1 antihistamine (product), H1 antihistamine (substance), H-1 Receptor Antagonist
French Antagonistes des récepteurs histaminergiques H1, Antihistamines H1, Antihistaminiques des récepteurs H1, Anti-histaminiques H1, Anti-histamines H1, Antihistaminiques H1, Antagonistes H1
Swedish Histamin H1-blockerare
Czech histamin H1 - antagonisté, histaminové H1-receptory - blokátory
Finnish Histamiini-H1-salpaajat
German Antagonisten, Histamin H1-Rezeptor-, Antagonisten, Histamin H1-, Histamin-H1-Rezeptor-Antagonisten, Histamin-H1-Rezeptorblocker, H1-Rezeptorblocker, Histamin H1-Blocker, ANTIHISTAMINIKA H 01, HISTAMIN REZEPTORENBLOCKER H1, HISTAMIN REZEPTOREN ANTAGONISTEN H1, HISTAMIN ANTAGONISTEN H 001, Antihistaminika, H1-, Histamin-H1-Antagonisten
Japanese 古典的抗ヒスタミン薬, ヒスタミンH1拮抗剤, ヒスタミンH1遮断薬, ヒスタミンH1受容体拮抗薬, ヒスタミンH1受容体遮断剤, 抗ヒスタミン剤H1, 古典的抗ヒスタミン剤, ヒスタミンH1受容器遮断薬, ヒスタミンH1アンタゴニスト, ヒスタミンH1受容体遮断薬, H1受容体拮抗薬, H1ブロッカー, H1受容体拮抗剤
Polish Antagoniści histaminy H1, Leki przeciwhistaminowe H1, Antyhistaminiki H1, Leki antyhistaminowe H1, Blokery receptora H1 histaminy, Antyhistaminiki klasyczne
Spanish antihistamínico H1 (producto), antihistamínico H1 (sustancia), antihistamínico H1, Antagonistas de Histamina H1, Antagonistas del Receptor H1 de Histamina, Antihistaminicos H1, Bloqueadores de los Receptores de Histamina H1, Antihistamínicos H1
Italian Antagonisti dell'istamina H1
Portuguese Antagonistas dos Receptores H1 de Histamina, Antagonistas dos Receptores H1, Anti-Histamínicos H1, Bloqueadores dos Receptores H1 de Histamina

Ontology: Hydroxyzine (C0020404)

Definition (CHV) a kind of antihistamine and mild anti-anxiety drug
Definition (MSH) A histamine H1 receptor antagonist that is effective in the treatment of chronic urticaria, dermatitis, and histamine-mediated pruritus. Unlike its major metabolite CETIRIZINE, it does cause drowsiness. It is also effective as an antiemetic, for relief of anxiety and tension, and as a sedative.
Definition (NCI) A piperazine derivative with antihistamine, antiemetic, and anxiolytic properties. Hydroxyzine's antihistaminic effect is due to its metabolite, cetirizine, a potent H1 receptor antagonist and selective inhibitor of peripheral H1 receptors. This agent competes with histamine for binding at H1-receptor sites on the effector cell surface. The sedative properties of hydroxyzine occur as a result of suppression of certain subcortical regions of the brain. Secondary to its central anticholinergic actions, hydroxyzine may be effective as an antiemetic.
Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH D006919
SnomedCT 372856003, 80165005
English Hydroxyzine, 2-(2-(4-((4-Chlorophenyl)phenylmethyl)-1-piperazinyl)ethoxy)ethanol, Ethanol, 2-(2-(4-((4-chlorophenyl)phenylmethyl)-1-piperazinyl)ethoxy)-, hydroxyzine, Hydroxyzine [Chemical/Ingredient], hydrOXYzine, Hydroxyzine (product), Hydroxyzine (substance), HYDROXYZINE
Swedish Hydroxizin
Czech hydroxyzin
Finnish Hydroksitsiini
Japanese アタラックス-P, ヒドロキシジンパモ酸塩, パモ酸ヒドロキシジン, アタラックスP, ジスロンP, 塩酸ヒドロキシジン, ジスロン, アタラックス, ヒドロキシジン, ハタナジン, ヒドロキシジン塩酸塩
Spanish hidroxizina (sustancia), hidroxicina (producto), hidroxicina, hidroxizina, hidroxizina (producto), Hidroxicina, Hidroxizina, hidroxicina (sustancia)
Polish Hydroksyzyna
French Hydroxyzine
German Hydroxyzin
Italian Idrossizina
Portuguese Hidroxizina

Ontology: Periactin (C0031017)

Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH D003533
English periactin, Periactin

Ontology: Atarax (C0684229)

Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH D006919
English atarax, ataraxs, Atarax

Ontology: Vistaril (C0936278)

Concepts Organic Chemical (T109) , Pharmacologic Substance(T121)
MSH D006919
English vistaril, Vistaril