Antihistamines, Decongestants, Antitussives, and Expectorants (Pharm E2)

diphenhydramine (Benadryl)

- Traditional antihistamine so causes sedating effects - Not recommended in older adults because of increased potential for falls and significant anticholinergic effects - Used for relief of allergies, motion sickness, Parkinson's disease, and promotion of sleep - Also used with Epi in management of anaphylaxis - Contraindicated in patients with known allergy to med, used with caution in nursing mothers, neonates, and patients with lower respiratory tract symptoms

loratadine (Claritin)

-Does not readily distribute into CNS so is non-sedating - However at higher doses (10 mg doses usually), drowsiness, HA and fatigue can be seen - Used to relieve the symptoms of seasonal allergic rhinitis as well as urticaria - Drug allergy is the only contraindication to the use of loratadine - Given PO, 24 hour duration of action, 1-3 hour onset, and 8-12 hour peak

The nurse notes in a Pt's med history that the Pt is taking benzonatate (Tessalon Perles) as needed. Based on this finding, the nurse interprets that the Pt has which problem? A- Cough B- Seasonal allergies C- Chronic rhinitis D- Motion Sickness

A Anesthetizes or numbs the cough receptors

When assessing a patient who is to receive a decongestant, the nurse will recognize that a potential contraindication would be which condition? SATA A- Glaucoma B- Fever C- HTN D- Peptic Ulcer Disease E- Allergic rhinitis

A, C

Dextromethorphan

Acts on medullary cough center directly PO, 15-30 minute onset, 2.5 hour peak, and 3-6 hour duration *Contraindicated* in: asthma or emphysema, persistent HA, hyperthyroidism, cardiac and vessel disease, HTN, glaucoma, and use of MAOIs in past 14 days *Adverse Effects*: dizziness, drowsiness, nausea

Contraindications of nasal decongestants

Adrenergic drugs are contraindicated in narrow angle glaucoma, uncontrolled CVS disease, HTN, diabetes, Asthma, history of CVA, BPH, and hyperthyroidism

Adverse Effects of nasal decongestants

Adrenergic drugs can cause nervousness, insomnia, palpitations, and tremor. Intranasal steroids can cause localized mucosal irritation and dryness. Topically absorbed adrenergic drugs can cause HTN, palpitations, HA, nervousness, and dizziness due to alpha receptor stimulation on heart, blood vessels, and CNS. REBOUND CONGESTION if used long term or abused

Non-sedating antihistamines

Also called peripherally acting antihistamines - *loratadine (Claritin)*, cetirizine (Zyrtec), and fexofenadine (Allegra) - Much longer acting and do not cross blood-brain barrier causing sedation

The nurse is reviewing a patient's medication orders for prn meds that can be given to a patient who has bronchitis with a productive cough. Which drug will the nurse choose? A- Antitussive B- Expectorant C- Antihistamine D- Decongestant

B

The nurse is giving an antihistamine and will observe the Pt for which side effects? SATA A- HTN B- Dizziness C - "Hangover" effect D - Drowsiness E- Tachycardia F- Dry mouth

B, C, D, F

When giving decongestants, the nurse must remember that these drugs have alpha-adrenergic-stimulating effects that may result in which effect? a) Fever b) Bradycardia c) Hypertension d) CNS depression

C

The nurse knows that an antitussive cough medication would be the best choice for which patient? A- Pt with productive cough B- Pt with chronic paranasal sinusitis C - Pt who has had recent abdominal surgery D - Pt who has influenza

C Would not want Pt to have hacking cough that would increase intra abdominal pressure causing complications

Opioid drugs used as antitussives

Codeine and Hydrocodone, however they are usually used in combination with other respiratory drugs and rarely used alone for purpose of cough suppression

MOA of antihistamines

Compete with histamine for unoccupied receptors on basophils and mast cells to prevent the release and actions of histamine stored within these cells. - They DO NOT push histamine off the receptors that are already binded, so meds work best when given early in a histamine-mediated reaction

Pt is taking a decongestant to help reduce symptoms of a cold. The nurse will instruct the Pt to observe for which possible Sx, which may indicate and adverse effect of this drug? A- Increased cough B- Dry mout C- Slower heart rate D - Heart palpitations

D Adrenergic (constrict vessels) can cause heart palpitations or tachycardia

Assessment for decongestants

Decongestants increase blood pressure and heart rate, so assess and document the patient's BP, pulse, and other vital parameters

Nonopioid drugs used as antitussives

Dextromethorphan and Benzonatate

Adverse Effects of antihistamines

Drowsiness is usually CC, anticholinergic effects (drying) such as dry mouth, changes in vision, difficulty urinating, and constipation; N/V/D, dizziness, hypotension, palpitations, syncope, nervousness or excitement

Expectorants

Guaifenesin

Histamine Receptors

H1= mediate smooth muscle contraction and dilation of the capillaries H2= mediate acceleration of the heart rate and gastric acid secretion - Physiologic changes: Constriction of smooth muscle especially in the stomach and lungs, increase in body secretions, vasodilation and increased capillary permeability which results in fluid out of blood vessels into tissues= drop in BP and edema

Special consideration about antihistamines

If allergy testing is to be performed, these medications are usually discontinued at least 4 days before testing, ONLY on a prescriber's order

Contraindications of antihistamines

Known drug allergy, not as sole therapy during asthma attacks, narrow angle glaucoma (anticholinergic effects), cardiac disease, kidney disease, HTN, bronchial asthma, COPD, peptic ulcer disease, seizure disorders, BPH, PREGNANCY, children under 2, and used with CAUTION in impaired liver and renal function, and lactating mothers.

Interactions of nasal decongestants

Monoamine oxidase inhibitors (MOAIs) may result in additive effects or toxicity when given with sympathomimetic drugs

Codeine

Potentially addictive and can depress respirations. PO, 15-30 minute onset, 35-45 minute peak, and 4-6 hour duration. *Contraindicated* in: known allergy, respiratory depression, increased ICP, seizure disorders, COPD, BPH, renal or liver diseases, and with alcohol *Adverse Effects*: sedation, N/V, lightheadedness, constipation

Indications for antitussives

Stop the cough reflex when the cough is NONPRODUCTIVE and/or harmful. Would NOT want to stop productive cough reflex, as that is the body clearing the secretions

MOA of Benzonatate

Suppresses the cough reflex by anesthetizing (numbing) the stretch receptor cells in the respiratory tract, which prevents reflex stimulation of the medullary cough center

oxymetazoline (Afrin)

Sympathomimetic drug that causes dilated arterioles to constrict, which reduces nasal blood flow and congestion. Should be used for NO MORE than 3 days at a time. Onset 10 minutes, 12 hour duration of action

Benzonatate

Tessalon Perles works by anesthetizing the cough receptors, PO route, 100 and 200 mg capsules, 15-20 minute onset and 3-8 hour duration *Contraindicated* in: known allergy to it and productive cough *Adverse Effects*: dizziness, HA, sedation, nausea, constipation, pruritus, and nasal congestion

Empiric Therapy

Treatment of cold is difficult due to fact virus cannot be readily identified; so empiric therapy is the treatment is rendered based on what is believed to be the most likely cause, given the presenting clinical symptoms. Meds ONLY treat the symptoms, not causative agent

Supplements and herbal products for respiratory

Vitamin C, Echinacea, and Goldenseal - Limited efficacy research, significant drug interactions

MOA of decongestants

adrenergic drugs constrict the blood vessels surrounding the nasal sinuses, making nasal secretions better able to drain either externally through nostrils or internally through reabsorption

3 groups used as decongestants

adrenergics (sympathetic mimic), anticholinergics, and corticosteroids

Intranasal Steroids

beclomethasone dipropionate, budesonide, flunisolide, *fluticasone (Flonase)*, triamcinolone, ciclesonide, *Atrovent (anticholinergic)*

Traditional (sedating histamine)

diphenhydramine (Benadryl), Promethazine

H1 antagonists/Antihistamine drugs

diphenhydramine (Benadryl), chlorpheniramine, fexofenadine (Allegra), loratadine (Claritin), and cetirizine (Zyrtec) - help alleviate the symptoms of cold, but do not cure it

Nasal Decongestants

ephedrine, oxymetazoline, phenylephrine, and tetrahydrozoline

Contraindications of Dextromethorphan

hyperthyroidism, advanced cardiac and vessel disease, HTN, glaucoma, and use of MAOIs in past 14 days, asthma or emphysema, HA, not recommended in pregnant women unless needed

MOA of expectorants

increasing hydration of the respiratory tract, this reduces viscosity of mucus which facilitates its removal

Indications of antihistamines

management of nasal allergies, seasonal or perennial allergic rhinitis, urticaria (hives), and some of the typical symptoms of the common cold. - Also useful in treatment of allergic reactions, motion sickness, Parkinson's (due to anticholinergic effects), vertigo, and sometimes as a sleep aid.

Adverse Effects of Guaifenesin

may cause nausea, vomiting, and gastric irritation

MOA of nasal steroids

nasal steroids are aimed at the inflammatory response elicited by antigens. They causes these cells that sound the alarm off or unresponsive. Goal is NOT immunosuppression, but reduce inflammatory symptoms

Contraindications of expectorants

only contraindication for Guaifenesin is known drug allergy, should not use these medications longer than 1 week and avoid alcohol

Assessment for ALL drugs in this chapter

rate, rhythm, and depth of respirations, breath sounds, presence of cough, and description of cough and sputum

Intranasal decongestants can cause

rebound congestion and lead to overuse and dependence on nasal spray

Indications of decongestants

reduce nasal congestion associated with acute or chronic rhinitis, common cold, sinusitis, and hay fever or other allergies. May also be used to reduce swelling of nasal passages to facilitate visualization of the nasal and pharyngeal membranes before surgery or diagnostic procedures

Indications for expectorants

relief of productive cough commonly associated with common cold, bronchitis, laryngitis, pharyngitis, pertussis, influenza, and measles. Also may be used as antitussives as thinning secretions may diminish tendency to cough

MOA of opioid antitussives and Dextromethorphan

suppress the cough reflex through direct action on the cough center in the medulla. Opioid antitussives also provide analgesia and increases viscosity of secretions= help reduce Sx such as runny nose and PND