Cough Treatment PDF

Cough Dr. Ibrahem Al-Adham Taken from Handbook of Nonprescription Drugs 18 Ed, chapter 12 Cough Cough is an important defensive respiratory reflex with potentially significant adverse physical and psychological consequences and economic impact. Cou...

Cough Dr. Ibrahem Al-Adham Taken from Handbook of Nonprescription Drugs 18 Ed, chapter 12 Cough Cough is an important defensive respiratory reflex with potentially significant adverse physical and psychological consequences and economic impact. Cough is the most common symptom for which patients seek medical care. Cough is initiated by stimulation of chemically and mechanically sensitive, vagally mediated sensory pathways in laryngeal, esophageal, and tracheobronchial airway epithelium.  Etiology of Cough Classification Etiology Acute Viral URTI, pneumonia, acute left ventricular failure, asthma, foreign body aspiration Subacute Post infectious cough, bacterial sinusitis, asthma Chronic UACS, asthma, GERD, COPD (chronic bronchitis), ACEIs, bronchogenic carcinoma, carcinomatosis, sarcoidosis (auto immune disease, left ventricular failure, aspiration secondary to pharyngeal dysfunction Key: ACEI = Angiotensin converting enzyme inhibitor; COPD = chronic obstructive pulmonary disease; GERD = gastroesophageal reflux disease; UACS = upper airway cough syndrome; URTI = upper respiratory tract infection Clinical Presentation of Cough Coughs are described as productive or nonproductive. A productive cough (a wet or “chesty” cough) expels secretions from the lower respiratory tract that, if retained, could impair ventilation and the lungs’ ability to resist infection. Productive coughs may be effective (secretions easily expelled) or ineffective (secretions present but difficult to expel). The appearance of the secretions is not always a reliable diagnostic indicator, but secretions are typically clear with bronchitis and purulent with bacterial infection. Anaerobic bacterial infections are associated with a distinct malodor. Nonproductive coughs (a dry or “hacking” cough), which are associated with viral and atypical bacterial infections, gastroesophageal reflux disease (GERD), cardiac disease, and some medications, serve no useful physiologic purpose. Clinical Presentation of Cough Common complications of cough include: exhaustion, insomnia, musculoskeletal pain, hoarseness, excessive perspiration, and urinary incontinence. Mechanical irritation from coughing may cause sore throat. Cough may cause prolonged absence from work or school, withdrawal from social activities, and fear that the cough is a symptom of a serious illness, such as cancer or tuberculosis. Treatment of Cough The primary goal of self treatment of cough is to reduce the number and severity of cough episodes. The second goal is to prevent complications. Cough treatment is symptomatic; the underlying disorder must be treated to stop the cough. General Treatment Approach Selection of a medication for selfcare of cough depends on the nature and etiology of the cough. Antitussives (cough suppressants) control or eliminate cough and are the drugs of choice for nonproductive coughs. Antitussives should not be used to treat productive cough unless the potential benefit outweighs the risk (e.g., significant nocturnal cough). Suppression of productive coughs may lead to retention of lower respiratory tract secretions, increasing the risk of airway obstruction and secondary bacterial infection. Protussives (expectorants) change the consistency of mucus and increase the volume of expectorated sputum and may provide some relief for coughs that expel thick, tenacious secretions from the lungs with difficulty.  Cough medications are marketed in a variety of dosage forms (syrups, liquids, solutions, suspensions, tablets, capsules, lozenges, oral granules, topical ointments and creams, topical patches, and vaporizer solutions). The Food and Drug Administration (FDA) allows various combinations of antitussives, protussives, analgesics, decongestants, and antihistamines. However, combinations of antitussives and protussives are potentially counterproductive. Nonpharmacologic Therapy Nonpharmacologic therapy includes non-medicated lozenges, humidification, interventions to promote nasal drainage, and hydration. Non-medicated lozenges may reduce cough by decreasing throat irritation. Humidifiers (ultrasonic, impeller, and evaporative) increase the amount of moisture in inspired air, which may soothe irritated airways. However, high humidity may increase environmental mold, dust mites, minerals, and microorganisms.  Nonpharmacologic Therapy Vaporizers (humidifiers with a medication well or cup for volatile inhalants) produce a medicated vapor. Coolmist humidifiers and vaporizers are preferred because fewer bacteria grow at the cooler temperatures and there is less risk of scalding if they are tipped over. Babies and young children up to about 2 years of age cannot blow their noses; a rubber bulb nasal syringe may be used to clear the nasal passages and reduce cough if postnasal drip causes cough. Propping infants upright when they sleep and raising the head of the bed at night promotes drainage of nasal secretions.  Pharmacologic Therapy Codeine: Codeine containing products must contain one or more non-codeine active ingredients and no more than 200 mg of codeine per 100 milliliters. Codeine acts centrally on the medulla to increase the cough threshold. The most common side effects are nausea, vomiting, sedation, dizziness, and constipation. Concomitant use of codeine and central nervous system (CNS) depressants (e.g., barbiturates, sedatives, or alcohol) causes additive CNS depression. Codeine is contraindicated in patients with known codeine hypersensitivity and during labor when a premature birth is anticipated. Patients with impaired respiratory reserve (e.g., asthma or COPD) or preexisting respiratory depression, drug addicts, and individuals who take other respiratory depressants or sedatives, including alcohol, should use codeine with caution. Dextromethorphan Considered approximately equipotent with codeine, dextromethorphan is a nonopioid with no analgesic, sedative, respiratory depressant, or addictive properties at usual antitussive doses. Dextromethorphan, the methylated dextrorotatory analogue of levorphanol (a codeine analogue), acts centrally in the medulla to increase the cough threshold. Dextromethorphan is indicated for the suppression of nonproductive cough caused by chemical or mechanical respiratory tract irritation. The efficacy and safety of dextromethorphan as an antitussive drug in children have not been established.  Dextromethorphan has a wide margin of safety. Side effects with usual doses are uncommon but may include drowsiness, nausea or vomiting, stomach discomfort, or constipation. Additive CNS depression occurs with alcohol, antihistamines, and psychotropic medications. The combination of monoamine oxidase inhibitors (MAOIs) and dextromethorphan may cause serotonergic syndrome (e.g., increased blood pressure, hyperpyrexia, arrhythmias, and myoclonus – contaction pf group of muscles). Dextromethorphan should not be taken for at least 14 days after the MAOI is discontinued.  Diphenhydramine Diphenhydramine, a nonselective (firstgeneration) antihistamine with significant sedating and anticholinergic properties, acts centrally in the medulla to increase the cough threshold. Second generation antihistamines (e.g., loratadine and fexofenadine) lack antitussive activity. Diphenhydramine is indicated for the suppression of nonproductive cough caused by chemical or mechanical respiratory tract irritation. Symptoms of diphenhydramine overdose include mild to severe CNS depression (e.g., mental confusion, sedation, or respiratory depression), hypotension, and CNS stimulation (e.g., hallucinations or convulsions).  Diphenhydramine side effects Diphenhydramine may cause excitability, especially in children. Diphenhydramine potentiates the depressant effects of narcotics, nonnarcotic analgesics, benzodiazepines, tranquilizers, and alcohol on the CNS, and it intensifies the anticholinergic effect of MAOIs and other anticholinergics. Diphenhydramine should be used with caution in patients with diseases potentially exacerbated by drugs with anticholinergic activity, including narrow angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction, symptomatic prostatic hypertrophy, bladder neck obstruction, asthma and other lower respiratory tract disease, elevated intraocular pressure, hyperthyroidism, cardiovascular disease, or hypertension. Because of the increased risk of toxicity, diphenhydramine containing antitussives should not be used with any other diphenhydramine containing product, including topical products  Chlophedianol Chlophedianol is a centrally acting oral antitussive originally marketed in 1960 as a prescription antitussive. Reintroduced as a nonprescription product in late 2009, chlophedianol is an alkylamine antihistamine derivative with antitussive, moderate local anesthetic, and mild anticholinergic effects. Chlophedianol is indicated for the suppression of nonproductive cough caused by chemical or mechanical respiratory tract irritation. Chlophedianol is marketed in the form of oral liquids, solutions, and syrups. Sugar, alcohol, dye, and gluten free products are available. Side effects include excitation, hyperirritability, nightmares, hallucinations, hypersensitivity, and urticaria. Dry mouth, vertigo, visual disturbances, nausea, vomiting, and drowsiness have been associated with large doses. If the patient takes MAOIs, chlophedianol should not be administered for at least 14 days after the MAOIs are halted.  Protussives (Expectorants) Guaifenesin (glyceryl guaiacolate), the only FDA approved expectorant, is indicated for the symptomatic relief of acute, ineffective productive cough. Guaifenesin is not indicated for chronic cough associated with chronic lower respiratory tract diseases such as asthma, COPD, emphysema, or smoker’s cough. Guaifenesin loosens and thins lower respiratory tract secretions, making minimally productive coughs more productive. However, few data support its efficacy, especially at nonprescription dosages.  Guaifenesin is marketed as oral liquids, syrups, caplets, granules, and immediate release and extended release tablets. Alcohol, sucrose, and dye free formulations are also available. Most reports of guaifenesin over dosages involve combinations of drugs and therefore are difficult to assess. Large doses, either singly or in combination with ephedrine or pseudoephedrine, have been associated with renal calculi.  Dosage Guidelines for Nonprescription Oral Antitussives and Expectorants Dosage (maximum daily dosage) Drug Adults/Children ≥12 Years Children 6 to