Symptomatic Treatment of the Common Coldand Influenza

Dr. Hulisz is Assistant Professor of Family Medicine, at Case Western Reserve University School of Medicine, and Associate Clinical Professor of Pharmacy Practice, at Ohio Northern University College of Pharmacy.

Introduction

The common cold is one of the oldest and most bothersome conditions affecting the population. Adults suffer an average of three to five episodes of the common cold per year.⁽¹⁾ Americans spend over $700 million annually on over-the-counter products alone for symptomatic relief due to the common cold.⁽²⁾ The common cold causes an estimated 23 million days of lost work productivity, or an average of almost 7 sick days per person annually in the United States.⁽³⁾ The common cold results in approximately 27 million physician visits annually in the United States, and drugs are prescribed or recommended in 94% of cases.⁽⁴⁾ The influenza virus is responsible for over 20,000 deaths annually and up to 300,000 hospitalizations in the United States.⁽⁵⁾ Geriatric patients infected with the influenza virus experience significant morbidity and mortality. The economic impact of past endemic outbreaks of influenza in the United States has been estimated at $1.5 billion to $3.5 billion in direct and indirect costs.⁽⁶⁾ Pharmacists are frequently consulted for advice on symptomatic relief of the common cold and influenza, and are uniquely qualified for this role.

Clinical PresentationThe common cold and influenza cause a constellation of symptoms that vary in type and intensity. The common cold often begins with a runny nose, sneezing, sore throat, mild headache or malaise, and may produce cough. There is often no fever, or only mild fever, and little if any gastrointestinal symptoms or other systemic symptoms. Influenza often produces a sudden onset of high fever, with marked chills, sweating, photophobia, severe headache, tiredness or extreme fatigue, body aches, and sometimes nausea and vomiting, which is not seen with the common cold. Influenza can also lead to secondary infections or potentially life-threatening complications, such as pneumonia in susceptible individuals. Thus, prevention and/or treatment is important, making interventions such as influenza vaccine potentially life-saving in some patients. The pharmacist should take a careful history from a patient to determine the exact time and intensity of cold and flu symptoms. Pharmacists can then make treatment recommendations to target specific symptoms and avoid unwanted side effects, since many products contain several active ingredients, some that may be unnecessary.

Nasal SymptomsAntihistamines

Antihistamines are commonly used for relief of rhinor-rhea (runny nose) and sneezing; however, their use is not without controversy, since controlled studies do not clearly support their use.⁽⁶⁾Antihistamines produce an atropine-like drying effect on mucous membranes and may actually impair flow of mucus.⁽⁷⁾ Antihistamines may be helpful, however, in relieving symptoms of pruritus secondary to allergic rhinitis (eg, hay fever), but do little to improve nasal congestion. Studies have shown that symptoms associated with the common cold, such as sneezing, runny nose, and stuffiness, are not caused by histamine release, but rather are caused by a virally induced release of kinins.⁽⁸⁾ Critical analysis of well-designed studies using antihistamines demonstrates little symptomatic relief of the common cold.^(6,9-12) An expert panel reached a consensus that antihistamines have no role in the management of upper respiratory tract infection, although they continue to be useful to treat allergy.⁽¹³⁾

Nonetheless, many patients do claim benefit in nasal symptoms, and many antihistamines are marketed as combination products. Some patients benefit from the sedating effects of first-generation agents (eg, chlor-pheniramine), especially when symptoms interfere with sleep. Antihistamines can cause drowsiness, dry mouth, blurred vision, and urinary retention. Patients with influenza with nausea may find antihistamines, such as diphenhydramine or dimenhydrinate, useful antiemetics. Contrary to early reports, antihistamines are not contraindicated for patients with asthma or chronic obstructive pulmonary disease. Second-and third-generation antihistamines, such loratadine and fexofenadine, respectively, have not been shown to be useful for treating cold and flu symptoms in the absence of allergy.

Counseling Patients on Antihistamine UsePharmacists should remind all patients receiving antihistamines that dizziness, sedation, confusion, dry mouth, and urinary retention can occur; these effects are likely to be more pronounced in geriatric patients. Older men with prostate disease, such as benign prostatic hyperplasia, are particularly susceptible to urinary retention. Patients should be counseled to take their first dose at a time when mental alertness is not required, such as bedtime. Pharmacists should discourage the use of alcoholic beverages with antihistamines because of additive central nervous system depressant effects. Pharmacists should remind patients that these drugs may impair motor activity; thus, it is unadvisable for patients to drive or operate heavy machinery when beginning an antihistamine.

Decongestants

Decongestants produce short-term relief of cold and flu symptoms, such as nasal congestion, and rhinorrhea to a lesser degree. These drugs have alpha-agonist effects, producing vaso-constriction of the nasal mucosa. Orally administered nasal deconges-tants are effective when used as directed, but have adverse effects that pharmacists are well aware of, such as cardiac and central nervous system stimulation. This may result in elevation of blood pressure, tachycardia, nervousness, and insomnia. Local (topical) administration is associated with rapid development of tachyphylaxis and rebound congestion (rhinitis medicamentosa). The topical nasal decongestant of choice is oxymetazo-line (Afrin). The oral decongestant of choice is pseudoephedrine. This agent is now perhaps the most widely used decongestant since many sympath-omimetics have been taken off the U.S. market.

Counseling Patients on Decongestant UsePharmacists should caution patients with uncontrolled hypertension, advanced coronary artery diseases, cardiac arrhythmias, diabetes, stroke, or thyroid disease that use of oral decongestants should be medically supervised. These drugs can cause an increase in arterial pressure, heart rate, and elevate blood glucose levels. Patients should not receive mono-amine oxidase (inhibitors while on these drugs. Because of the central nervous system activation seen with pseudoephedrine and similar drugs, patients should be counseled to expect some mild jitteriness or insomnia.

The usual adult dose of pseu-doephedrine is 60 mg up to every 6 hours, but no more than 240 mg daily. Patients receiving oxymetazoline nasal spray should be counseled not to overuse this product, as this may lead to rebound congestion. Generally, patients should restrict their use to two to three sprays in each nostril twice a day for no more than 5 consecutive days.

Ipratropium Nasal Spray

The anticholinergic agent ipra-tropium is available to treat the runny nose associated with colds and flu. The available product is Atrovent 0.06% nasal spray. The dose is two sprays per nostril three to four times daily. This is an effective prescription medication for rhinorrhea; however, it is quite expensive. Ipratropium is also available in a 0.03% strength for treating the runny nose associated with allergy. While the nasal spray is very effective in stopping a runny nose, it does little to relieve nasal congestion and sneezing.

Counseling Patients Ipratropium Use

Patients should limit their use of ipratropium to no more than 4 consecutive days, and be advised that the product will not relieve sneezing or congestion. Pharmacists should remind patients not to exceed the prescribed dosage, since this agent is capable of producing profound dryness of the nasal mucosa, which may lead to nose bleeds in some patients.

HumidificationNonpharmacologic approaches, such as hydration, humidification, and steam inhalation, to the treatment of the common cold and influenza are used to help liquify upper respiratory tract secretions. While some studies using heated vapor inhalation produced both subjective and objective benefits,^(14,15) other studies demonstrate little benefit in treating the common cold.(16-18)Cool mist humidifiers are also used for symptomatic relief of the common cold. Although several sources recommend the use of humidifiers, no recent, well-designed studies document their efficacy in treating cold symptoms.^(2,7) Additional benefits of using humidifiers in treating the upper respiratory tract have been proposed, including prevention of damage to mucous membranes from dry air and moistening of dry, irritated nasal epithelia.^(18,19) The experience of this author is that many patients report a reduction in the severity and frequency of upper respiratory symptoms with the use of cool mist humidifiers.

Fever, Headache, Myalgia, Sore ThroatMost patients with influenza, and some patients with the common cold will experience significant fever, sore throat, headache, muscle aches and pains (myalgia), and occasional joint pain (arthralgia), for which simple analgesics, such as acet-aminophen or nonsteroidal anti-inflammatory drugs (NSAIDs), are quite effective. Sore throat may also be relieved by oral demulcents or local anesthetics, such as dyclonine lozenges.

Counseling Patients on Analgesic Use

Pharmacists should encourage the use of acetaminophen as the analgesic of choice for cold and flu symptoms of pain and fever in both children and adults.

Aspirin and other salicylates should be avoided in children less than 18 years of age because of its possible association with Reye's syndrome. While NSAIDs are generally safe and well tolerated by many patients, some have experienced serious, life-threatening toxicity with these medications, particularly adverse gastrointestinal events. Patients at risk for NSAID-induced gastrointestinal injury include the elderly, patients with a history of gastrointestinal bleeding, those on corticos-teroids, warfarin, or antiplatelet therapy, and those with a history of intolerable dyspepsia with other NSAIDs. NSAIDs may also prolong bleeding time and cause adverse renal effects in susceptible patients. Pharmacists should take a medical history before dispensing NSAIDs, especially in elderly patients.

Pharmacist Counseling TipsIn addition to the aforementioned drug-specific counseling points, pharmacists should also discourage indiscriminate antibiotic use for colds and flu, in part by educating patients. These efforts if widely practiced can help to curtail the problem of bacterial resistance. Patients with severe flu symptoms that persist beyond 3 to 5 days should be referred for medical care, especially if vomiting, persistent fever, or lower respiratory symptoms are present. Likewise, patients with cough or cold symptoms that last 7 to 10 days or longer should see their physician, especially if symptoms worsen. Pharmacists should counsel patients to maintain adequate hydration in the winter months, wash their hands frequently, not smoke, exercise regularly, get enough sleep and rest, and eat properly.

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