CapseraAllergy
10 source-linked study cards in this body system.
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How each medicine works
Medicines in this body system: 10
| Cetirizine — Metabolite of hydroxyzine; selective peripheral H1-receptor antagonist. |
| Loratadine — Second-generation antihistamine; blocks peripheral histamine H1 receptors. |
| Azelastine — Phthalazinone derivative with histamine H1-receptor antagonist activity; metabolite desmethylazelastine is also active. |
| Levocetirizine — The active enantiomer of cetirizine selectively inhibits H1 receptors. In vitro, its human H1-receptor affinity was about twice that of cetirizine; the clinical relevance of this comparison is unknown. |
| Promethazine — Phenothiazine H1 receptor blocker with sedative and antiemetic effects and weak dopamine antagonism. |
| Epinephrine — Non-selective alpha/beta agonist: raises BP via positive inotropy, positive chronotropy and peripheral vasoconstriction. |
| Fexofenadine — The selected label identifies it as an antihistamine but does not state a molecular mechanism. |
| Diphenhydramine — Antihistamine with anticholinergic and sedative effects; antihistamines appear to compete with histamine for receptor sites on effector cells. |
| Pseudoephedrine — Promotes norepinephrine release from adrenergic nerve endings; norepinephrine acts at alpha receptors in nasal blood vessels, producing vasoconstriction and decongestion. |
| Cyproheptadine — Serotonin and histamine antagonist with anticholinergic and sedative effects; these drugs appear to compete with serotonin and histamine at receptor sites. |
Each summary is the mechanism line from the medicine’s study card.
Listed most often on cards in this body system
Common side effects
Dizziness · 3/10: Promethazine, Diphenhydramine, Pseudoephedrine
Drowsiness · 2/10: Cetirizine, Promethazine
Headache · 2/10: Azelastine, Epinephrine
Somnolence · 2/10: Azelastine, Levocetirizine
Dry mouth · 2/10: Levocetirizine, Promethazine
Sedation · 2/10: Promethazine, Diphenhydramine
Interactions
Alcohol · 2/10: Cetirizine, Azelastine
Boxed warning
1/10: Promethazine
An item counts as shared only when both cards use the same wording. If a card does not list an item, that is not a statement that the effect never occurs.