Antihistamines, antitussives , decongestants, expectorants

1. Antihistamines, antitussives, decongestants, expectorants Snotty snotwell

2. As part of an immune response to foreign pathogens, histamine is produced by basophils and by mast cells when contacting the antigen. Mast cells found at site of likely injury…nose,mouth, feet, GI tract, respiratory,blood vessels. Histamine will bind with certain receptors on cells to give different results. Histamine is also a brain neurotransmitter.

3. H1 receptor found in smooth muscle, endothelial cells. histamine will cause increase of permeability of vessel wall and brochoconstriction, runny nose. H2 receptor found in stomach and vascular smooth muscle cells histamine will cause gastric acid increase and vasodilation. H3 receptor found in CNS tissue. Histamine yields decreased neurotransmitters. H4 receptor found in basophils,bone marrow. deals with chemotaxis.

4. Two main effects of anaphylactic shock on the body are severe drops in blood pressure and impaired respiration. The drastic drop in blood pressure develops from the severe peripheral vasodilation and the increased permeability of the capillaries. The impaired breathing arises from bronchoconstriction. The anaphylactic reaction occurs very rapidly after the introduction of the antigen into the patient. Unless prompt action is taken by medically trained personnel, the patient will die in a matter of minutes. The drug used for anaphylactic shock is epinephrine.

5. antihistamines • Action- competes with histamine due to similar structure. for treatment of allergies, insomnia, rash, and prophylaxis for drug allergies • Adverse reactions- drying up body fluids, drowsiness, and hyperactivity in some children • Considerations- these are the antidote for overdose in anitpsychotic meds, and do not mix with alcohol- synergistic effect

6. Some antihistamine drugs • Zyrtec- allergies • Allergra- allergies • Benadryl- allergies • Anti-vert- dizziness • Phenergan- vomiting

7. antitussives • action- supresses cough • Indicated for nonproductive coughs! • Opioid and non-opioid (narcotic and non-narcotic) • Mechanism of Action-- • Opioids---Suppress the cough reflex by direct action on the cough center in the medulla • examples: codeine (Robitussin A-C, Dimetane- DC) Hydrocodone • Onset: 15-30 min

8. Non-opioids/non-narcotic (less effective)------ • Suppress the cough reflex by anesthetizing the • stretch receptors in the respiratory tract and • preventing the cough reflex from being stimulated • by the medulla center in the brain • examples: benzonatate (Tessalon Perles)dextromethrophan (Vicks Formula 44, Robitussin-DM) • Onset: 15-30 min • Reactions- depression, light-headedness • Considerations- dextromethorphan reacts with • MAOI’s(antidepressants) • due to the potential for seratonin syndrome, which is a potentially life-threatening • condition that can occur rapidly, due to a buildup of an excessive amount of serotonin • benzonatate must be swallowed not chewed.may cause • choking feeling, chest painn or numbness, hallucination, confusion.

9. antitussives • Tesselon perles • Robitussin • Benadryl • Codeine • hydrocodone

10. decongestants • Action- stimulates alpha adrenergic receptor to constrict arteries within the nasal mucosa. many cells have these receptors, to stimulate sympathetic NS. • Treats congestion from cold, sinusitis and infections • Reactions- increased blood pressure, increased heart rate, insomnia, anxiety, tremors, rebound effect(re-emergence of symptoms when med is DC) • Considerations- should be avoided by patient who have DM, heart disease, enlarged prostate, tourette’s syndrome

11. decongestants • Afrin----oxymetazoline • Sudafed--pseudoephedrine • Zyrtec---cetirizine-pseud…. • allegra--fexofenadine-psedo… • claritin---loratadine-pseu….

12. expectorants • Action- decrease thickness of mucus to remove or cough out of the lungs. increase bronchial secretion • Reactions- vomiting and GI distress • Special considerations- drink plenty of water

13. Expectorants • guaifenesin----Robitussin • Mucinex-D----guaifenesin/pseudoephedrine • Robutussin AC---guaifenesin/codeine