{"id":205,"date":"2019-11-12T17:22:48","date_gmt":"2019-11-12T17:22:48","guid":{"rendered":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/chapter\/5-6-antihistamines\/"},"modified":"2025-01-16T22:26:00","modified_gmt":"2025-01-16T22:26:00","slug":"5-6-antihistamines","status":"publish","type":"chapter","link":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/chapter\/5-6-antihistamines\/","title":{"raw":"5.6 Antihistamines","rendered":"5.6 Antihistamines"},"content":{"raw":"Diphenhydramine is an example of a first-generation antihistamine. (See Figures 5.7[footnote]\u201cBenadryl Allergy USA<\/a>\u201d by ZenBenjamin<\/a> is licensed under CC BY-NC-SA 2.0<\/a>[\/footnote]<\/sup> and 5.8.[footnote]\u201cdiphenhydramine (1)<\/a>\u201d by Intropin<\/a> is licensed under CC BY-NC 2.0<\/a>[\/footnote]<\/sup>) Second-generation antihistamines were developed to have fewer side effects. An example of a second-generation antihistamine is cetirizine.\n\nMechanism of Action: <\/strong>Antihistamines have the following mechanisms of action: block histamine at H1 receptors; inhibit smooth muscle constriction in blood vessels and the respiratory and GI tracts; and decrease capillary permeability, salivation, and tear formation.\n\nIndications: <\/strong>Antihistamines are used for relief of allergy or cold symptoms.\n\nNursing Considerations: <\/strong>This medication is not safe for children under the age of 2 years without a health care provider's order.\n\nSide Effects\/Adverse Effects: <\/strong>First-generation medications can cause anticholinergic effects (such as dry mouth, urinary retention, constipation and blurred vision). CNS depression or CNS stimulation with excessive doses can occur, especially in children. First-generation antihistamines should be used with caution in the elderly.\n\nSecond-generation medications may cause headache, nausea, vomiting, dysmenorrhea, and fatigue.[footnote]Frandsen, G., & Pennington, S. (2018). Abrams\u2019 clinical drug: Rationales for nursing practice <\/em>(11th ed.). Wolters Kluwer.[\/footnote]<\/sup>\n\nHealth Teaching & Health Promotion: <\/strong>Clients should be advised that antihistamines may cause drowsiness, and concurrent use of alcohol or other CNS depressants should be avoided. Clients should take only the recommended amount of medication and not exceed dosing recommendations. Some clients may experience side effects such as dry mouth, and frequent oral hygiene may assist in alleviating discomfort.[footnote]uCentral from Unbound Medicine. https:\/\/www.unboundmedicine.com\/ucentral<\/a>[\/footnote]<\/sup>\n\n \n\n[caption id=\"attachment_204\" align=\"aligncenter\" width=\"339\"]\"Photo Figure 5.7 Diphenhydramine, a First-Generation Antihistamine Available Orally or IV Medication[\/caption]\n\n \n\n[caption id=\"attachment_204\" align=\"aligncenter\" width=\"259\"]\"Photo Figure 5.8 Diphenhydramine HCl Preparation, Single-Dose Vial for IV Administration[\/caption]\n\nNow let's take a closer look at the medication grid for diphenhydramine and cetirizine in Table 5.6.[footnote]This work is a derivative of Pharmacology Notes: Nursing Implications for Clinical Practice<\/a> by Gloria Velarde<\/a> licensed under CC BY-NC-SA 4.0<\/a>[\/footnote],<\/sup>[footnote]Frandsen, G., & Pennington, S. (2018). Abrams\u2019 clinical drug: Rationales for nursing practice <\/em>(11th ed.). Wolters Kluwer.[\/footnote],[footnote]This work is a derivative of DailyMed<\/a> by U.S. National Library of Medicine<\/a> in the Public Domain<\/a>. [\/footnote] <\/sup>Medication grids are intended to assist students to learn key points about each medication class. Basic information related to a common generic medication in this class is outlined, including administration considerations, therapeutic effects, and side effects\/adverse effects. Prototype\/generic medication listed in the medication grid is also linked to a free resource from the U.S. National Library of Medicine called DailyMed<\/a>. Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.\n\nTable 5.6 Diphenhydramine and Cetirizine Medication Grid\n\n\n\n\n\n
\n
Class\/Subclass<\/strong><\/h5>\n<\/th>\n
\n
Prototype\/Generic<\/strong><\/h5>\n<\/th>\n
\n
Nursing Considerations<\/strong><\/h5>\n<\/th>\n
\n
Therapeutic Effects<\/strong><\/h5>\n<\/th>\n
\n
Side\/Adverse Effects<\/strong><\/h5>\n<\/th>\n<\/tr>\n
First-generation Antihistamine<\/th>\ndiphenhydramine<\/a><\/td>\nTake as directed\n\nAvoid alcohol or CNS depressants due to sedation<\/td>\nTemporarily relieves symptoms due to hay fever or other upper respiratory allergies: Runny nose; sneezing; itchy, watery eyes; itching of the nose or throat\n\nTemporarily relieves symptoms due to the common cold such as runny nose and sneezing<\/td>\nSedation\n\nAnticholinergic effects\n\nGastrointestinal: Nausea and vomiting\n\nParadoxical effect: Excitation in children<\/td>\n<\/tr>\n
Second-generation Antihistamine<\/th>\ncetirizine<\/a>\n\nloratadine<\/a><\/td>\nTake as directed\n\nAvoid allergens\n\nAvoid alcohol or CNS depressants due to sedation<\/td>\nTemporarily relieves symptoms due to hay fever or other upper respiratory allergies: Runny nose; sneezing; itchy, watery eyes; itching of the nose or throat<\/td>\nNon-sedating\n\nAnticholinergic effects\n\nGastrointestinal: Nausea and vomiting\n\nParadoxical effect: Excitation in children<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n ","rendered":"

Diphenhydramine is an example of a first-generation antihistamine. (See Figures 5.7[1]<\/sup><\/a><\/sup> and 5.8.[2]<\/sup><\/a><\/sup>) Second-generation antihistamines were developed to have fewer side effects. An example of a second-generation antihistamine is cetirizine.<\/p>\n

Mechanism of Action: <\/strong>Antihistamines have the following mechanisms of action: block histamine at H1 receptors; inhibit smooth muscle constriction in blood vessels and the respiratory and GI tracts; and decrease capillary permeability, salivation, and tear formation.<\/p>\n

Indications: <\/strong>Antihistamines are used for relief of allergy or cold symptoms.<\/p>\n

Nursing Considerations: <\/strong>This medication is not safe for children under the age of 2 years without a health care provider’s order.<\/p>\n

Side Effects\/Adverse Effects: <\/strong>First-generation medications can cause anticholinergic effects (such as dry mouth, urinary retention, constipation and blurred vision). CNS depression or CNS stimulation with excessive doses can occur, especially in children. First-generation antihistamines should be used with caution in the elderly.<\/p>\n

Second-generation medications may cause headache, nausea, vomiting, dysmenorrhea, and fatigue.[3]<\/sup><\/a><\/sup><\/p>\n

Health Teaching & Health Promotion: <\/strong>Clients should be advised that antihistamines may cause drowsiness, and concurrent use of alcohol or other CNS depressants should be avoided. Clients should take only the recommended amount of medication and not exceed dosing recommendations. Some clients may experience side effects such as dry mouth, and frequent oral hygiene may assist in alleviating discomfort.[4]<\/sup><\/a><\/sup><\/p>\n

 <\/p>\n

\"Photo
Figure 5.7 Diphenhydramine, a First-Generation Antihistamine Available Orally or IV Medication<\/figcaption><\/figure>\n

 <\/p>\n

\"Photo
Figure 5.8 Diphenhydramine HCl Preparation, Single-Dose Vial for IV Administration<\/figcaption><\/figure>\n

Now let’s take a closer look at the medication grid for diphenhydramine and cetirizine in Table 5.6.[5]<\/sup><\/a>,<\/sup>[6]<\/sup><\/a>,[7]<\/sup><\/a> <\/sup>Medication grids are intended to assist students to learn key points about each medication class. Basic information related to a common generic medication in this class is outlined, including administration considerations, therapeutic effects, and side effects\/adverse effects. Prototype\/generic medication listed in the medication grid is also linked to a free resource from the U.S. National Library of Medicine called DailyMed<\/a>. Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication.<\/p>\n

Table 5.6 Diphenhydramine and Cetirizine Medication Grid<\/p>\n\n\n\n\n\n
\n
Class\/Subclass<\/strong><\/h5>\n<\/th>\n
\n
Prototype\/Generic<\/strong><\/h5>\n<\/th>\n
\n
Nursing Considerations<\/strong><\/h5>\n<\/th>\n
\n
Therapeutic Effects<\/strong><\/h5>\n<\/th>\n
\n
Side\/Adverse Effects<\/strong><\/h5>\n<\/th>\n<\/tr>\n
First-generation Antihistamine<\/th>\ndiphenhydramine<\/a><\/td>\nTake as directed<\/p>\n

Avoid alcohol or CNS depressants due to sedation<\/td>\n

Temporarily relieves symptoms due to hay fever or other upper respiratory allergies: Runny nose; sneezing; itchy, watery eyes; itching of the nose or throat<\/p>\n

Temporarily relieves symptoms due to the common cold such as runny nose and sneezing<\/td>\n

Sedation<\/p>\n

Anticholinergic effects<\/p>\n

Gastrointestinal: Nausea and vomiting<\/p>\n

Paradoxical effect: Excitation in children<\/td>\n<\/tr>\n

Second-generation Antihistamine<\/th>\ncetirizine<\/a><\/p>\n

loratadine<\/a><\/td>\n

Take as directed<\/p>\n

Avoid allergens<\/p>\n

Avoid alcohol or CNS depressants due to sedation<\/td>\n

Temporarily relieves symptoms due to hay fever or other upper respiratory allergies: Runny nose; sneezing; itchy, watery eyes; itching of the nose or throat<\/td>\nNon-sedating<\/p>\n

Anticholinergic effects<\/p>\n

Gastrointestinal: Nausea and vomiting<\/p>\n

Paradoxical effect: Excitation in children<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

 <\/p>\n

  1. \u201cBenadryl Allergy USA<\/a>\u201d by ZenBenjamin<\/a> is licensed under CC BY-NC-SA 2.0<\/a> ↵<\/a><\/li>
  2. \u201cdiphenhydramine (1)<\/a>\u201d by Intropin<\/a> is licensed under CC BY-NC 2.0<\/a> ↵<\/a><\/li>
  3. Frandsen, G., & Pennington, S. (2018). Abrams\u2019 clinical drug: Rationales for nursing practice <\/em>(11th ed.). Wolters Kluwer. ↵<\/a><\/li>
  4. uCentral from Unbound Medicine. https:\/\/www.unboundmedicine.com\/ucentral<\/a> ↵<\/a><\/li>
  5. This work is a derivative of Pharmacology Notes: Nursing Implications for Clinical Practice<\/a> by Gloria Velarde<\/a> licensed under CC BY-NC-SA 4.0<\/a> ↵<\/a><\/li>
  6. Frandsen, G., & Pennington, S. (2018). Abrams\u2019 clinical drug: Rationales for nursing practice <\/em>(11th ed.). Wolters Kluwer. ↵<\/a><\/li>
  7. This work is a derivative of DailyMed<\/a> by U.S. National Library of Medicine<\/a> in the Public Domain<\/a>. ↵<\/a><\/li><\/ol><\/div>","protected":false},"author":83,"menu_order":6,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[48],"contributor":[],"license":[],"class_list":["post-205","chapter","type-chapter","status-publish","hentry","chapter-type-numberless"],"part":186,"_links":{"self":[{"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/pressbooks\/v2\/chapters\/205","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/wp\/v2\/users\/83"}],"version-history":[{"count":1,"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/pressbooks\/v2\/chapters\/205\/revisions"}],"predecessor-version":[{"id":206,"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/pressbooks\/v2\/chapters\/205\/revisions\/206"}],"part":[{"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/pressbooks\/v2\/parts\/186"}],"metadata":[{"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/pressbooks\/v2\/chapters\/205\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/wp\/v2\/media?parent=205"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/pressbooks\/v2\/chapter-type?post=205"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/wp\/v2\/contributor?post=205"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/accnursingpharmacology\/wp-json\/wp\/v2\/license?post=205"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}