Memorizing Pharmacology Video 3 of 7
Allergies plague many of our patients. There are many different medications used to treat this disease and its important to be able to tell the difference....
In this third video, I cover respiratory medications for allergies, cough, asthma, and anaphylactic shock.
Antihistamines: We’ll start with two antihistamine generations, 1st and 2nd. First generation causes drowsiness and is shorter acting, while second generation is non-sedating and longer acting. Recall we already learned a different set of antihistamines in the first video, the H2 receptor blockers for acid reflux. Stems are sometimes similar, -atadine vs. -tidine, so be careful.
Decongestants: Pseudoephedrine is only available behind the pharmacy counter (BTC) and often paired with a 2nd generation antihistamine as the “hyphen ‘D’,” on the end of a drug name. Phenylephrine is often marked as “P.E.” and is available over the counter (OTC). Finally, oxymetazoline, brand Afrin is only meant for a few days of use to avoid rebound congestion.
Allergic rhinitis: Anti-inflammatories like triamcinolone produce fewer side effects with a nasal spray formulation. Full effects may take a few weeks, but steroid nasal sprays are hands down the best prophylaxis for seasonal allergies.
Expectorants / antitussives / oral steroids: Expectorants like guaifenesin help remove mucus and antitussives suppress the urge to cough. The choice of antitussive often depends on cough severity. Oral steroids like prednisone and methylprednisolone reduce severe inflammation sometimes from this cough.
Asthma: Asthma is straightforward, an inflammatory condition paired with bronchoconstriction. Our drugs then work as anti-inflammatories and bronchodilators. An inhaled steroid with long-acting beta-2 agonist is a common combination. While patients can safely use an inhaled steroid like fluticasone alone, in certain conditions beta-2 agonists like salmeterol must be paired with an inhaled steroid for safety.
Anticholinergics: Also relax bronchial smooth muscle for asthma and COPD and include short-acting ipratropium and long-acting tiotropium inhaled forms.There is also non-inhaler asthma therapy. Leukotriene inhibitors such as montelukast and the biologic omalizumab have their place in respiratory therapy.
Anaphylaxis: Epinephrine is part of the LEAN acronym, lidocaine, epinephrine, atropine, and naloxone for critical emergency medicines.
It’s sometimes easier to see the divisions in outline rather than paragraph form of the major classes.
Antihistamines1st GenerationDiphenhydramine2nd GenerationCetirizineLoratadineLoratadine-D
DecongestantsPseudoephedrine - BTCPhenylephrine - OTCOxymetazoline – nasal spray, rebound congestion, 3 days max
Allergic rhinitisTriamcinolone – no proper stem
CoughGuaifenesin / dextromethorphan (DM)Guaifenesin / codeine (AC)
Oral SteroidsMethylprednisolonePrednisoneBoth use “pred” as prefix or infixAsthma
Steroid and long acting beta-2 agonistBudesonide / formoterol (Symbicort)Fluticasone / salmeterol (Advair)Nasal / oral steroidFluticasone comes as both nasal (Flonase) and oral (Flovent) formShort acting rescue inhalerAlbuterolAnticholinergic / beta-2 agonistIpratropium / albuterol (Duoneb)Anticholinergic aloneTiotropium – long actingLeukotriene inhibitorMontelukast
Anti- IgE antibodyOmalizumab – monoclonal antibody
AnaphylaxisEpinephrine also known as adrenaline
Last edit by TonyPharmD on Jul 6 : Reason: Add pathophysiologic class.