Antihistamines

Block the release of histamines from basophiles and mast cells in the blood Antihistamines for the tx of allergies But also for insomnia, rashes, hay fever, to prevent drug reactions and for dizziness Side effect: some cause drowsiness, dry up the mouth and body fluids, hyperactivity however in kids! They are “anti-cholinergic” in effect by blocking parasympathetic NS transmitter i.e. acetylcholine May raise one’s BP!

Old school antihistamines Dimetapp (oral) Periacin (oral) Benadryl (diphenhydramine) often we use its side effect of drowsiness as a safe sleeping people (Sominex, SleepEze, etc.) but cause dry mouth and raise BP as well so careful. Vistaril (hydroxyzine) Antivert (meclizine) is an antihistamine but uses its side effect of balance for vertigo and seasickness Phenergan (promethazine) is antihistamine but we use its side effect to prevent nausea therefore it comes in a suppository

Examples of new age antihistamines Zyrtec (cetirizine) oral Allegra (Fexofenadine) oral Claritin (loratadine) oral All three are new school types; no drowsiness, safer and don’t raise BP and cause dryness in mouth, can’t be used for nausea or sleep because don’t’ have those side effects!

Antitussives (prevent coughing) Codeine Dextromethorphan (Robitussin DM) Hydrocodone (hycodone) Promethazine

Decongestants Constrict arteries in your nasal mucosa (adrenergic!) like adrenalin to reduce mucous production Good for URI’s, sinusitis, colds However, adrenergic so they raise BP, prevent sleep, agitate youngsters, tachycardia, tremors, Avoid with HBP and DM (raises blood sugar like adrenalin does), avoid hyperthyroid pts.

Ex. Of decongestants Afrin (oxymetazoline) Neosynephrine (phenylephrine) Pseudoephedrine (Sudaphed) all are nasal sprays All cause HBP

combinations Zyrtec D, Allegra D, Claritin D all have pseudophed mixed in with them so you have an antihistamine PLUS a decongestant

Expectorants Decrease the thickness of your mucous, make it watery so you can cough it up and release mucous plugs in your lungs (to “expectorate” which means to produce mucous in your cough, not a dry useless cough) Ex. Guanifenesin (Robitussin)