Antihistamines Flashcards
How to know the first Generation antihistamine drugs
Drugs having EN and ending with -INE- and -ATE-
List first generation H1 blockers
Diphenhydramine
Chlorpheniramine
Dimenhydrniate
A first generation antihistamine and is a serotonin antagonist
Cyproheptadine
What are h1 blockers used for
Used to treat
Urticaria
Angio edema
Allergic rhinitis
What are first generation antihistamines sedative
They are lipophilic and can cross BBB
How can sedative effects of first generation H1 blockers be used
Could be used in sleeping disorders
First generation H1 blockers antihistamine side effects
Antihistamine- sedation, increase appetite and increase weight
Anti muscarinic- dilated pupils, drymouth and blurred vision
Anti-a-adrenergic - orthostatic hypotension and dizziness and tremors
Which first generation H1 blockers are the most potent at sedation
Hydrooxyzine and promethazine
Which first generation H1 blockers have antiemetic effects
Dimenhydrinate and promethazine
Which first generation H1 blockers can treat motion sickness
Dimenhydrinate and Diphenhydramine
Suffix of second generation H1 blockers
Drugs ending in -adine- except acrivastine
List 2nd generation H1 blockers
Loratidine, desloratadine and fexofenadine ++ acrivastine and cetrizine
What’s special about cetirizine and levocetirizine
Can produce sedation
What’s the difference between first and second generation H1 blockers
Have far less lipid solubility so has less sedative side effects in the brain and less antimascarinic side effects
Which generation is most preferred
2nd generation
What is bilastine
New 2nd generation H1 blocker used for allergic rhinitis and chronic urticaria, importantly doesn’t impair performance so can be given to pilots and personnel in safety sensitive jobs
What is rupatadine
Dual H1 and platelet activation factor receptor antagonist and inhibitor of mast cell degranulation.
What is rupatadine indicated for
Seasonal rhinitis and chronic spontaneous urticaria
When is antihistamine and effective and when is it not
Antihistamines compete with histamine binding at unoccupied receptors, block action of histamine but can’t push histamine off the receptor so it should be given early in the treatment
How is fexofinadine excreted
It passes through the liver and doesn’t get metabolised and goes to the bile
How are most antihistamines excreted
They are changed in to inactive metabolites and then go to the bike
How is cetirizine and levocetirizine excreted
Through kidneys and in urine
Which herb has antihistamine qualities
Ginger
