p.3
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What type of receptors are all histamine receptors classified as?
G-protein Coupled Receptors (GPCRs).
p.3
H1 Receptor Antagonists: Effects and Pharmacokinetics
What are the effects of H1 receptor activation?
Bronchoconstriction, contraction of the gut, and vascular dilation.
p.3
Clinical Applications of Anti-Allergy Drugs
What is the significance of H4 receptors in the immune system?
They are involved in chemotaxis and are promising candidates for treating inflammatory conditions.
p.1
Corticosteroids: Mechanism of Action and Clinical Use
What role do corticosteroids play in allergic disease management?
Corticosteroids are used in the management of allergic diseases.
p.3
H2 Receptor Antagonists: Effects and Pharmacokinetics
What is the primary function of H2 receptors?
Acid secretion by gastric parietal cells.
p.1
Clinical Applications of Anti-Allergy Drugs
What are some common allergic diseases mentioned?
Allergic rhinitis, dermatitis, asthma, and severe cases of anaphylaxis.
p.12
Adverse Effects of Anti-Allergy Medications
What is a systemic adverse effect of corticosteroids?
Depression, Growth suppression, Osteoporosis.
p.1
Other Anti-Allergic Medications
What are mast cell stabilizers used for?
They are usually used for the treatment of asthma.
p.11
Other Anti-Allergic Medications
What action do leukotriene inhibitors perform?
They block cys-LT1 receptors and provide modest clinical benefit in asthma.
p.11
Clinical Applications of Anti-Allergy Drugs
What is the mechanism of action of epinephrine in allergies?
It induces rapid bronchodilation and inhibits antigen-induced release of inflammatory mediators from mast cells.
p.9
Corticosteroids: Mechanism of Action and Clinical Use
What is the primary action of corticosteroids in asthma?
They suppress the multi-level inflammatory response.
p.10
Corticosteroids: Mechanism of Action and Clinical Use
What is the common dosing frequency for inhaled corticosteroids (ICS)?
ICS should be given twice daily, with some like Budesonide, Mometasone, Ciclesonide, and Fluticasone suitable for once daily dosing.
p.5
H1 Receptor Antagonists: Effects and Pharmacokinetics
How do H1 antagonists affect edema formation in humans?
They effectively suppress edema formation.
p.5
H1 Receptor Antagonists: Effects and Pharmacokinetics
What central nervous system effects can 1st generation H1 antagonists have?
They can both stimulate and depress the CNS, causing restlessness or somnolence.
p.6
H1 Receptor Antagonists: Effects and Pharmacokinetics
Which metabolic pathway is primarily responsible for the metabolism of most H1 antagonists?
Most are metabolized by CYP enzymes in the liver.
p.9
Corticosteroids: Mechanism of Action and Clinical Use
When should systemic steroids be considered in asthma treatment?
When lung function is less than 30% predicted and there is no significant improvement with nebulized beta-2 agonists.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
What is the role of H4 receptors in the immune system?
They are associated with cellular shape change, chemotaxis, cytokine secretion, and upregulation of adhesion molecules.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
How does histamine affect inflammatory cells?
It has an active chemotactic attraction to inflammatory cells such as neutrophils and eosinophils.
p.7
Differences Between 1st and 2nd Generation H1 Antagonists
Why are first-generation antihistamines not recommended for children?
Their sedative effects can impair learning and school performance.
p.7
Clinical Applications of Anti-Allergy Drugs
What is the primary use of drugs under the class Ethanolamines?
Mild sedation and anti-motion sickness.
p.8
H1 Receptor Antagonists: Effects and Pharmacokinetics
What is the effect of Hydroxyzine?
Long-acting, used for skin allergies and has sedative effects.
p.5
H1 Receptor Antagonists: Effects and Pharmacokinetics
Which 1st generation H1 antagonist is most effective in combating motion sickness?
Promethazine, due to its strong muscarinic blocking activity.
p.10
Adverse Effects of Anti-Allergy Medications
What are some local side effects of inhaled corticosteroids?
Dysphonia, oropharyngeal candidiasis, and cough.
p.1
Introduction to Anti-Allergy Medications
What is the importance of studying anti-allergy medications?
To address the increase in allergic diseases, manage drug overuse, and improve clinical decision-making.
p.1
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What are the four classes of receptors that histamine acts through?
H1, H2, H3, and H4 receptors.
p.6
H1 Receptor Antagonists: Effects and Pharmacokinetics
What local anesthetic activity is associated with some H1 antagonists?
Some H1 antagonists have local anesthetic activity, with Promethazine being especially active.
p.6
Drug Interactions with H1 Receptor Antagonists
What are the potential drug interactions with H1 receptor antagonists?
They can interact with drugs that induce CYP synthesis or inhibit CYP isoforms, leading to reduced or elevated plasma levels.
p.10
Adverse Effects of Anti-Allergy Medications
What are some systemic side effects associated with long-term use of corticosteroids?
Adrenal suppression, growth suppression, bruising, osteoporosis, cataracts, and metabolic abnormalities.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
What are the direct cardiac effects of histamine when given intravenously?
They are overshadowed by baroreceptor reflexes stimulated by reduced blood pressure.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
What cardiovascular effects do H1 receptor antagonists inhibit?
They prevent vasodilation, increase in capillary permeability, and hypotension.
p.3
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What role do H3 receptors play in histaminergic neurons?
They act as auto-receptors that inhibit histamine release.
p.3
Adverse Effects of Anti-Allergy Medications
What is the 'triple response of Lewis' associated with histamine injection?
Local reddening, a flare extending beyond the injection site, and wheel or swelling at the injection site.
p.9
Corticosteroids: Mechanism of Action and Clinical Use
What structural changes occur during asthma?
Hyperresponsiveness of the respiratory airway, leading to symptoms like coughing and bronchospasm.
p.9
Pharmacokinetics of Corticosteroids in Asthma
How are corticosteroids metabolized in the body?
They are metabolized in the liver and may undergo first-pass metabolism.
p.7
Clinical Applications of Anti-Allergy Drugs
What combination is used to treat nausea and vomiting during pregnancy?
Doxylamine + Vitamin B6 (Pyridoxine).
p.3
Adverse Effects of Anti-Allergy Medications
What is the role of H1 receptors in capillary permeability?
H1 receptor activation increases capillary permeability, leading to edema.
p.5
Differences Between 1st and 2nd Generation H1 Antagonists
What distinguishes 2nd generation H1 antagonists from 1st generation?
2nd generation H1 antagonists have lesser sedative effects and do not cross the blood-brain barrier.
p.9
Corticosteroids: Mechanism of Action and Clinical Use
What is the role of corticosteroids in reducing vascular permeability?
They prevent and reverse the increase of vascular permeability due to inflammatory mediators.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
What are the stimulatory functions of neuronal histamine in the CNS?
Promotes wakefulness, cognition, locomotion, energy metabolism, and nociception.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
Where is histamine generally found in low concentrations?
In plasma and other body fluids.
p.5
H1 Receptor Antagonists: Effects and Pharmacokinetics
What effect do H1 receptor antagonists have on gastric acid secretion?
They do not suppress gastric acid secretion; this is the function of H2 receptors.
p.11
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What is the role of mast cells and eosinophils in asthma?
Once activated, they trigger arachidonic acid metabolism, leading to airway inflammation.
p.6
Adverse Effects of Anti-Allergy Medications
What serious side effect can occur with early 2nd generation agents like Terfenadine and Astemizole?
Lethal ventricular arrhythmias can occur when combined with certain antifungal or macrolide antibiotics.
p.9
Corticosteroids: Mechanism of Action and Clinical Use
What is the initial intravenous steroid of choice for severe asthma?
Hydrocortisone, due to its rapid onset.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
How do patients with bronchial asthma respond to histamine?
They are much more sensitive to the bronchoconstrictor effects of histamine.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
Do H1 receptor antagonists suppress gastric acid secretion?
No, gastric acid secretion is primarily the function of H2 receptors.
p.12
Other Anti-Allergic Medications
What type of medication is Montelukast?
An anti-leukotriene inhibitor.
p.1
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
How is histamine synthesized?
Histamine is synthesized from histidine via decarboxylation.
p.5
H1 Receptor Antagonists: Effects and Pharmacokinetics
Are H1 receptor antagonists effective in blocking bronchoconstriction due to asthma?
No, they are ineffective in blocking bronchoconstriction due to asthma.
p.5
Differences Between 1st and 2nd Generation H1 Antagonists
What are some examples of 2nd generation H1 antagonists?
Cetirizine, desloratadine, fexofenadine, olopatadine, and ketotifen.
p.7
Differences Between 1st and 2nd Generation H1 Antagonists
What distinguishes 2nd generation H1 receptor antagonists from 1st generation?
They are not lipophilic and cannot cross the blood-brain barrier, resulting in less sedative effects.
p.11
Other Anti-Allergic Medications
What is pseudoephedrine primarily used for?
Temporary relief of stuffy nose and sinus pain and pressure caused by infection or allergic conditions.
p.8
Clinical Applications of Anti-Allergy Drugs
What is the primary use of Loratadine?
Mainly for allergic rhinitis.
p.9
Pharmacokinetics of Corticosteroids in Asthma
What is the absorption route for inhaled corticosteroids?
They are absorbed from the airway and alveolar surfaces.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
What is the function of H1 receptor antagonists in allergy treatment?
They act as inverse agonists to suppress cholinergic effects of the inflammatory response.
p.7
Adverse Effects of Anti-Allergy Medications
What side effects are not observed with 2nd Generation H1 antagonists?
Dryness of the mouth and respiratory passages, urinary retention or frequency, and dysuria.
p.1
Differences Between 1st and 2nd Generation H1 Antagonists
What are the two generations of H1 receptor antagonists?
1st Generation: Diphenhydramine, Chlorpheniramine, Hydroxyzine, Promethazine, Meclizine; 2nd Generation: Cetirizine, Levocetirizine, Fexofenadine, Loratadine, Desloratadine.
p.3
Adverse Effects of Anti-Allergy Medications
How does histamine affect systemic blood pressure?
It causes depression of systemic blood pressure.
p.7
Differences Between 1st and 2nd Generation H1 Antagonists
Which generation of H1 receptor antagonists is recommended for elderly patients?
Second Generation H1 Receptor Antagonists.
p.6
H1 Receptor Antagonists: Effects and Pharmacokinetics
How are H1 receptor antagonists absorbed in the body?
They are well absorbed in the GI tract and rapidly absorbed after oral administration.
p.5
Adverse Effects of Anti-Allergy Medications
What is a common side effect of overdose with 1st generation H1 antagonists?
Central excitation leading to convulsions, particularly in infants.
p.6
H1 Receptor Antagonists: Effects and Pharmacokinetics
How long do the effects of 1st generation H1 antagonists last?
Effects last 4 to 6 hours, although some drugs are longer acting.
p.5
H1 Receptor Antagonists: Effects and Pharmacokinetics
What is the effect of 1st generation H1 antagonists on muscarinic cholinergic responses?
They tend to inhibit muscarinic cholinergic responses.
p.10
Pharmacokinetics of Corticosteroids in Asthma
What is a unique characteristic of Ciclesonide?
Ciclesonide is a pro-drug converted to its active metabolite by esterases in the lungs, resulting in low bioavailability and a high therapeutic index.
p.10
Other Anti-Allergic Medications
What is the action of Ipratropium bromide?
It is an anticholinergic drug that prevents cholinergic-induced bronchoconstriction and decreases mucus secretions.
p.12
H1 Receptor Antagonists: Effects and Pharmacokinetics
Why is Levocetirizine preferred for allergic rhinitis in a call center agent?
It has less sedative effects.
p.11
Adverse Effects of Anti-Allergy Medications
What are the common side effects of anti-allergy medications?
Dry mouth, tachycardia, glaucoma, and urinary retention.
p.8
Corticosteroids: Mechanism of Action and Clinical Use
What is the primary action of corticosteroids in inflammatory conditions like asthma?
To switch off multiple inflammatory genes.
p.8
Corticosteroids: Mechanism of Action and Clinical Use
What is the mechanism of action of corticosteroids during asthma?
They bind to cytosolic Glucocorticoid Receptor proteins, forming receptor-ligand complexes that suppress gene transcription.
p.10
Pharmacokinetics of Corticosteroids in Asthma
Which inhaled corticosteroids have lower oral bioavailability than Beclomethasone?
Budesonide, Fluticasone, Mometasone, and Ciclesonide.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
What sensory defects does histamine stimulate in the epidermis and dermis?
It causes itch in the epidermis and pain, sometimes accompanied by itching, in the dermis.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
Where are high concentrations of histamine found?
In tissues containing large numbers of mast cells such as skin, bronchial mucosa, and intestinal mucosa.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What are the two mechanisms of histamine release?
Immunologic Release and Chemical/Mechanical Release.
p.8
H1 Receptor Antagonists: Effects and Pharmacokinetics
What class does Diphenhydramine belong to?
Ethanolamine, 1st Gen H1 Receptor Antagonist.
p.9
Corticosteroids: Mechanism of Action and Clinical Use
What is the recommended route of administration for corticosteroids in acute asthma exacerbation?
Inhaled corticosteroids are the first-line therapy.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
What is the dominant influence of H1 receptors in human bronchial smooth muscles?
They have a plasmogenic influence that causes contraction.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What is the process of histamine formation?
It is formed by decarboxylation of L-Histidine, catalyzed by L-Histidine decarboxylase.
p.7
Clinical Applications of Anti-Allergy Drugs
What caution is advised for pregnant patients regarding antihistamines?
Antihistamines can cross the placenta.
p.1
Adverse Effects of Anti-Allergy Medications
What is a common adverse effect of anti-allergy medications?
Sedation, especially with 1st generation H1 receptor antagonists.
p.1
Clinical Applications of Anti-Allergy Drugs
What is the significance of knowing drug indications and contraindications for anti-allergy medications?
It enhances clinical decision-making in managing allergic diseases.
p.6
Adverse Effects of Anti-Allergy Medications
What additional side effects can occur due to the anti-muscarinic action of some first-generation H1 antagonists?
Dryness of the mouth, urinary tension, dysuria, and allergic dermatitis.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What role does histamine play in gastric acid secretion?
It plays an important role in gastric acid secretion.
p.6
H1 Receptor Antagonists: Effects and Pharmacokinetics
What is the peak blood concentration time for H1 receptor antagonists?
Peak blood concentration occurs in 1 to 3 hours.
p.11
Adverse Effects of Anti-Allergy Medications
What are the potential neuropsychiatric side effects associated with Montelukast?
Increased risk of serious neuropsychiatric events, including suicidal thoughts.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What type of receptors are the four histamine receptors?
G protein-coupled receptors (GPCRs).
p.3
Pharmacokinetics of Corticosteroids in Asthma
What is the effect of H2 receptor stimulation on cyclic AMP?
It increases cyclic AMP and leads to feedback inhibition of histamine release.
p.11
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What are the effects of cysteinyl leukotrienes in asthma?
They induce bronchoconstriction, airway hyperresponsiveness, plasma exudation, mucus secretion, and eosinophilic inflammation.
p.11
Other Anti-Allergic Medications
How are leukotriene inhibitors administered?
Orally and are relatively well tolerated.
p.6
Differences Between 1st and 2nd Generation H1 Antagonists
What is a significant difference between 1st and 2nd generation H1 antagonists regarding CNS effects?
1st generation H1 antagonists can enter the CNS and cause sedation, while 2nd generation drugs typically do not.
p.10
Other Anti-Allergic Medications
What is the main action of mast cell stabilizers?
Blocking triggered induced asthma, such as exercise-induced asthma.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
How does histamine affect smooth muscle contractions?
It directly contracts or relaxes extravascular smooth muscles via H1 and H2 receptors.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
How does histamine function in the nervous system?
As a neurotransmitter and neuromodulator of both CNS and PNS.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What is the role of H2 receptors in histamine release?
They mediate a negative feedback control mechanism that modulates histamine release.
p.7
Adverse Effects of Anti-Allergy Medications
What are the symptoms of acute poisoning with first-generation H1 antagonists?
Hallucinations, excitement, ataxia, incoordination, athetosis, convulsions, fixed dilated pupils, flushed face, sinus tachycardia, urinary retention, dry mouth, and fever.
p.7
Clinical Applications of Anti-Allergy Drugs
What is the use of Olopatadine?
For allergic rhinitis and allergic conjunctivitis.
p.9
Corticosteroids: Mechanism of Action and Clinical Use
How do corticosteroids affect eosinophils in asthma?
They decrease the number of circulating eosinophils, reducing inflammatory responses.
p.10
Other Anti-Allergic Medications
What is Cromolyn Sodium and its historical significance?
Cromolyn Sodium is a mast cell stabilizer that was popular in the past for its safety profile but has declined in use due to more effective inhaled corticosteroids.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
What triggers immunologic release of histamine?
Exposure of mast cells and basophils to appropriate antigens, causing granulation.
p.9
Pharmacokinetics of Corticosteroids in Asthma
What is the excretion route for most corticosteroids?
They are excreted via urine, bile, or feces after being conjugated with sulfates or glucuronides.
p.4
H1 Receptor Antagonists: Effects and Pharmacokinetics
What can large doses of histamine cause during systemic anaphylaxis?
A profound progressive fall in blood pressure.
p.2
Histamine: Distribution, Biosynthesis, and Pharmacodynamics
How is histamine stored in the body?
After synthesis, it is stored in secretory granules in mast cells and basophils.
