Respiratory Antihistamines

Ajouté : 2026-06-07

[00:00:00]all right so we're gonna go here to the first generation antihistamines um and these um are used usually for allergies right they're used for mild allergic reactions so seasonal allergic rhinitis cough urticaria mild transfusion reactions these kinds of things um they're also used in anaphylaxis but they're not the first drug that's given the first drug that's given in anaphylaxis write this down is epinephrine right um so but this is given then um sometime thereafter um it can also be used with insomnia because it does have some sedating effects right side effects uh depending on what you're giving this for drowsiness or dizziness can be a side effect do want to let you know it doesn't list this within your reading but there is a certain amount of the population that will have a paradoxical reaction to this and instead of drowsiness and dizziness will actually have an excitatory effect anticholinergic effects include dry mouth constipation those kinds of things okay and so when people have dry mouth they can chew on um gum or they can have a hard candy things like that all right therapeutically you already know that it's used for allergic reactions sleep and for some extra pyramidal symptoms it can be used for right so it's contraindicated in newborns just makes them way too sleepy not safe so therefore is contraindicated in breastfeeding it does cross into the milk narrow angle glaucoma is problematic with this because of the anticholinergic effects here prosthetic hypertrophy again because of the anticholinergic effects and then acute asthma exacerbation we want people to know this is not a rescue med for acute asthma exacerbation that's pretty much what we're going on there um cns depressants um can be additive with this so that does mean that people will likely have an increased risk of respiratory depression if they're already on another cns depressant so this drug will make people extremely drowsy um and so so they have made second generation antihistamines so biochemically works very similar it's an antagonist to the h1 histamine receptor sites um used a lot in um allergies it usually lasts the preparations that are out there usually last a little longer they're often 12 and 24-hour preparations and they're not as sedating as the first generations thank goodness right because those first generations are pretty sedating for a lot of people so people can have anticholinergic side effects but the anticholinergic side effects are less than the first generations um so that's also an added benefit drowsiness and fatigue not as much as the first generations these second generation antihistamines can cause toxic levels of theophylline if taken with theophylline again cns depressants are additive but not as much as the first generation doses are lower in those with kidney or liver problems otherwise the levels tend to accumulate completely contraindicated in infants and in breastfeeding really not well studied as far as that's concerned so we want to take precaution with impaired liver and or kidney um problems any problems with the liver and or the kidney it can be taken with or without food um and so people will often take this prophylactically um but it can be um taken reactively it's just often times these don't act quite as fast as the benadryl so but look at the individual medication pull them up you know this is where we've got our citrazine um we've got our allegra um we've got all these these different um types of of second generation antihistamines