Pharmacology Study Guide

Antihistamines, Decongestants, Antitussive, and Expectorants
Antihistamines: Substances capable of reducing the physiologic and pharmacologic effects of histamine, including a wide variety of drugs that block histamine receptors.
Indications: Management of: nasal allergies, seasonal or perennial allergic rhinitis (hay fever), allergic reactions, motion sickness, Parkinson’s disease, sleep disorders. Also used to relieve symptoms associated with the common cold, Sneezing, runny nose, Palliative treatment, not curative
Key Drugs: * loratadine (Claritin)- is nonsedating antihistamine. It needs to be taken only once a day. These drug cannot distribute into the CNS, which alleviates the sedative effect associated with traditional antihistamine. Loratadine is used to relieve the symptoms of seasonal allergic rhinitis ( hay fever) as well as chronic urticaria.

* diphenhydramine (Benadryl- is an older, traditional antihistamine that works both peripherally and centrally. It also has potent anticholinergic and sedative effects. Still often used as a hypnotic drug because of sedating effects. It is used for the relief or prevention of histamine- mediated allergies and motion sickness, treatment of Parkinson's disease ( due to the anticholinergic effect).

Adverse Effects: * Anticholinergic (drying) effects, most common * Dry mouth * Difficulty urinating * Constipation * Changes in vision * Mild drowsiness to deep sleep

Interaction: * Ketoconazole, cimetidine, and erythromycin may increase concentrations of loratadine * Alcohol, monoamine oxidase inhibitors (MAOIs), and CNS depressants may increase the CNS depressant effects of diphenhydramine and cetirizine. * Antihistamine may be potentiated excessively interaction with apple, grapefruit and orange juice as well as with St. John's wort

Nursing Implications * Gather data about the condition or allergic reaction that required treatment; also assess for drug allergies * Contraindicated in the presence of acute asthma attacks and lower respiratory diseases, such as pneumonia * Use with caution in increased intraocular pressure, cardiac or renal disease, hypertension, asthma, COPD, peptic ulcer disease, BPH, or pregnancy * Instruct patients to report excessive sedation, confusion, or hypotension * Instruct patients to avoid driving or operating heavy machinery; advise against consuming alcohol or other CNS depressants * Instruct patients not to take these medications with other prescribed or over-the-counter medications without checking with prescriber * Best tolerated when taken with meals—reduces GI upset * If dry mouth occurs, teach patient to perform frequent mouth care, chew gum, or suck on hard candy (preferably sugarless) to ease discomfort * Monitor for intended therapeutic effects

Decongestants: Drugs that reduce congestion or swelling especially of the upper or lower respiratory tract
Indications: Relief of nasal congestion associated with: * Acute or chronic rhinitis * Common cold * Sinusitis * Hay fever * Other allergies * May also be used to reduce swelling of the nasal passage and facilitate visualization of the nasal/pharyngeal membranes before surgery or diagnostic procedures

Key Drugs:

* naphazoline (Privine) When these drugs are administered intransally the cause dilated arterioles to constrict, which reduces nasal blood flow and congestion.

Adverse Effects:
Adrenergics Steroids * Nervousness Local mucosal dryness * Insomnia and irritation * Palpitations * Tremors * (Systemic effects caused by adrenergic stimulation of the heart, blood vessels, and CNS)

Nursing Implications: * Decongestants may cause hypertension, palpitations, and CNS stimulation—avoid in patients with these conditions * Patients on medication therapy for hypertension should check with their physician before taking over-the-counter decongestants * Assess for drug allergies * Patients should avoid caffeine and caffeine-containing products * Report a fever, cough, or other symptoms lasting longer than a week * Monitor for intended therapeutic effects

Antitussives: A drug that reduces coughing, often by inhibiting neural activity in cough center of the central nervous system

Indications: * Used to stop the cough reflex when the cough is nonproductive and/or harmful

Key Drugs: * dextromethorphan is a nonopioid antitussive that is available alone or in combination with many other cough and cold preparations. It is widely use because it is safe and nonaddicting and does not cause respiratory or CNS depression, when used in recommended dosages.

Adverse Effects: * Dextromethorphan * Dizziness, drowsiness, nausea * Opioids * Sedation, nausea, vomiting, lightheadedness, constipation

Nursing Implications:

* Perform respiratory and cough assessment, and assess for allergies * Instruct patients to avoid driving or operating heavy equipment because of possible sedation, drowsiness, or dizziness * Patients taking chewable tablets or lozenges should not drink liquids for 30 to 35 minutes afterward * Report any of the following symptoms to the caregiver: * Cough that lasts more than a week * A persistent headache * Fever * Rash * Antitussive drugs are for nonproductive coughs * Monitor for intended therapeutic effects

Expectorants: Drugs that increase the flow of fluid in the respiratory tract, usually by reducing the viscosity of bronchial and tracheal secretions, and facilitate their removal by coughing and ciliary action
Indications:
* Used for the relief of productive coughs associated with: * Common cold * Bronchitis * Laryngitis * Pharyngitis * Coughs caused by chronic paranasal sinusitis * Pertussis * Influenza * Measles

Key Drugs: guaifenesin (Mucinex) is a very commonly used expectorant. Is use in the sympotomatic management of cough of varying origin. Beneficial in the treatment of productive coughs because it thins mucus in the respiratory tract that is difficult to cough up. Adverse Effects: * guaifenesin (Mucinex) :Nausea, vomiting, gastric irritation

Nursing Implications:

* Expectorants should be used with caution in the elderly or those with asthma or respiratory insufficiency * Patients taking expectorants should receive more fluids, if permitted, to help loosen and liquefy secretions * Report a fever, cough, or other symptoms lasting longer than a week * Monitor for intended therapeutic effects

Empiric therapy: A method of treatment disease based on observations and experience without a knowledge of the precise cause of or mechanism responsible for the disorder or the way in which therapeutic drug or produces improvement or cure.

Chapter 37: Bronchodilators and Other Respiratory Drugs
Beta-Agonists:
Indication * In Relief of bronchospasm related to asthma, bronchitis, and other pulmonary diseases * Used in treatment and prevention of acute attacks * Used in hypotension and shock
Used to produce uterine relaxation to prevent premature labor
Key Drugs: * albuterol (Proventil): bronchodilating beta agonists

* salmeterol (Serevent): is long acting beta 2 agonist bronchodilator. Is used for the maintenance treatment of asthma and COPD. Because of long acting , it should never be used for acute treatment. *
Adverse Effect
Beta2 albuterol (Proventil) * Hypotension OR hypertension * Vascular headache * Tremor

Nursing Implications: * Encourage patients to take measures that promote a generally good state of health so as to prevent, relieve, or decrease symptoms of COPD * Avoid exposure to conditions that precipitate bronchospasm (allergens, smoking, stress, air pollutants) * Adequate fluid intake * Compliance with medical treatment * Avoid excessive fatigue, heat, extremes in temperature, caffeine * Encourage patients to get prompt treatment for flu or other illnesses, and to get vaccinated against pneumonia or flu * Encourage patients to always check with their physician before taking any other medication, including over-the-counter medications * Perform a thorough assessment before beginning therapy, including: * Skin color, Baseline vital signs, Respirations (should be between 12 and 24 breaths/min), Respiratory assessment, including pulse oximetry, Sputum production, Allergies, History of respiratory problems, Other medications * Teach patients to take bronchodilators exactly as prescribed * Ensure that patients know how to use inhalers and MDIs, and have patients demonstrate use of the devices * Monitor for adverse effects * Monitor for therapeutic effects: Decreased dyspnea, Decreased wheezing, restlessness, and anxiety, Improved respiratory patterns with return to normal rate and quality, Improved activity tolerance * Decreased symptoms and increased ease of breathing * Beta-agonist derivatives * Albuterol, if used too frequently, loses its * beta2-specific actions at larger doses * As a result, beta1 receptors are stimulated, causing nausea, increased anxiety, palpitations, tremors, and increased heart * Beta-agonist derivatives (cont’d) * Ensure that patients take medications exactly as prescribed, with no omissions or double doses * Inform patients to report insomnia, jitteriness, restlessness, palpitations, chest pain, or any change in symptoms
Inhalers: Patient Education * For any inhaler prescribed, ensure that the patient is able to self-administer the medication * Provide demonstration and return demonstration * Ensure that the patient knows the correct time intervals for inhalers * Provide a spacer if the patient has difficulty coordinating breathing with inhaler activation * Ensure that the patient knows how to keep track of the number of doses in the

Leukotriene Receptor Antagonists

Indication: * Used for the prophylaxis and long-term treatment of asthma in adults and children 12 years of age and older * Montelukast is approved for use in children ages 2 and older, and for treatment of allergic rhinitis

Key Drugs * montelukast (Singulair) Use primimarily for oral prophylaxis and long-term treatment of asthma. Not recommend for treatment of acute asthma attacks

Adverse Effects:
Montelukast has fewer adverse effects
Interactions:

Phenobarbital decrease montelukast concentration

Nursing Implication:

* Ensure that the drug is being used for chronic management of asthma, not acute asthma * Teach the patient the purpose of the therapy * Improvement should be seen in about
1 week * Advise patients to check with physician before taking over-the-counter or prescribed medications—there are many drug interactions * Assess liver function before beginning therapy * Teach patient to take medications every night on a continuous schedule, even if symptoms improve