Antihistamines Flashcards
There are three (3) prototype medications, generations, can you name them?
1st generationH2 antagonist 2nd generation H₁ antagonist & Intranasal antihistamines
Name 3- 1st generationH2 antagonist?
Diphenhydramine- Benadryl Promethazine,-(Phenergan) Dimenhydrinate, Hydroxine- Vistaril
Name some second generation antihistamines
Loratadine-(Claritin), Cetirzine (Zrytect), Fexofenadine (Allegra), Desloratadine (Clarinex)
What is the action of an antihistamine?
Block histamine, hence histamine is a chemical released during inflammation that increases secretions and narrows airways
When or what is the use of an antihistamine?
Mild seasonal allergies, Anaphylaxis, Motion sickness, Insomnia & often used in combination with sympathomimetics to provide a nasal decongestant effect
What are adverse effects or complications of taking an antihistamine?
Sedation, Anticholinergic effects (dry mouth, constipation) GI upset , Acute toxicity, Resp depression & tissue injury at IV site
How does a client present in acute toxicity of an antihistamine?
Flushes face, high fever, tachy, dry mouth, urine retention, pupil dilatation
What is the antidote for antihistamine toxicity?
Activate charcoal & a cathartic to decrease the absorption, administer acetaminophen for fever & ice packs or sponge baths
Promethazine ( Phenergan) can cause what adverse effects?
Resp depression & tissue injury at IV site, - IM is the preferred route if unavailable, administer through a large-bore IV in concentration of 25 mg/mL or less-monitor & instruct the client to report manifestations of extravasation- burning or pain at site.
What are complications /precautions with an antihistamine?
Use with caution who have asthma, seizure disorder, cardiac & renal disease, urinary retention, open-angle glaucoma, & prostate hypertrophy, Pregnancy, & contraindicated during the third trimester, & Promethazine is contraindicated in children< 2 years, Use with caution in older adults dues to resp depression
What are drug interactions with antihistamines?
ETOH, and meds causing CNS depression-opioids, barbiturates, & benzos
What does an expectorant do ?
Liquefy the lower resp tract secretions
Why are expectorants used?
For the relief of resp conditions characterized by a nonproductive cough
What is a common expectorant?
Guaifenesin (Mucinex)
What are contraindications of an expectorant?
Do not use with persistent coughs, which could indicate an underlying medical problem.