Difelikefalin (Korsuva – Vifor), an IV kappa opioid receptor (KOR) agonist, has been approved by the FDA for treatment of moderate to severe pruritus associated with chronic kidney disease (CKD) in adults on hemodialysis. It is the first drug to be approved for this indication and the first KOR agonist to become available in the US. Difelikefalin has not been studied in patients on peritoneal dialysis.

The choice of drugs for treatment of allergic rhinitis depends on the severity of symptoms and whether they are intermittent or persistent (see Table 1).

View the Comparison Table: Some Oral Drugs for Allergic Rhinitis

The goal of asthma treatment is to control symptoms, prevent exacerbations, and maintain normal lung function. Management of acute exacerbations of asthma in the emergency department is not discussed here.

The FDA is requiring stronger warnings in the labeling of the leukotriene receptor antagonist montelukast (Singulair, and generics) about the risk of suicidal behavior and other serious neuropsychiatric events associated with its use.

The goal of asthma treatment is to control symptoms and prevent exacerbations. Management of acute exacerbations of asthma is not discussed here.

Allergic rhinitis can be classified as seasonal, perennial, or episodic. It is often associated with allergic conjunctivitis, rhinosinusitis, and asthma.

H₁-ANTIHISTAMINES — Oral – Oral second-generation H₁-antihistamines are the preferred first-line treatment for relief of the itching, sneezing, and rhinorrhea that characterize mild-to-moderate allergic rhinitis. They are less effective for nasal congestion.

View the Comparison Table: Some Oral Drugs for Allergic Rhinitis

INHALATION DEVICES — Metered-dose inhalers (MDIs) require coordination of inhalation with hand-actuation of the device. Valved holding chambers (VHCs) or spacers help some patients, especially young children and the elderly, use MDIs effectively. VHCs have one-way valves that prevent the patient from exhaling into the device, minimizing the need for coordinated actuation and inhalation. Spacers are tubes or chambers placed between the canister and a face mask or mouthpiece, which also avoids the need to coordinate actuation and inhalation. Both VHCs and spacers retain the larger particles emitted from the MDI, decreasing their deposition in the oropharynx and leading to a higher proportion of small respirable particles being inhaled.

The use of drugs to prevent and control symptoms of allergic disorders can be optimized when patients avoid exposure to specific allergens and/or environmental conditions that trigger or worsen their symptoms.

Inhalation is the preferred route of delivery for most asthma drugs. Chlorofluorocarbons (CFCs), which have ozone-depleting properties, are being phased out as propellants in metered-dose inhalers. Non-chlorinated hydrofluoroalkane (HFA) propellants, which do not deplete the ozone layer, are being used instead.

No truly new drugs have been approved for treatment of asthma since omalizumab (Xolair) in 2003, but some randomized controlled trials of older drugs have been published, and new guidelines have become available.

Allergic rhinitis, allergic conjunctivitis, atopic dermatitis, urticaria, anaphylaxis and asthma (reviewed in Treatment Guidelines 2005; 3:33 and not included here), are prevalent worldwide, especially in industrialized countries. Pharmacologic treatment of these disorders continues to improve in efficacy and safety. In addition to using drugs to prevent and control the symptoms of their allergic diseases, patients should also be instructed to avoid, if possible, specific allergens and/or environmental conditions that trigger or worsen their symptoms.

Montelukast (Singulair - Merck) is an oral cysteinyl leukotriene D₄ receptor antagonist originally marketed for treatment of asthma. It was approved by the FDA in 2003 for treatment of seasonal allergic rhinitis and recently for use in perennial allergic rhinitis in adults and children ≥ 6 months old. Intranasal corticosteroids have generally been considered the most effective drugs available for prevention and treatment of allergic rhinitis.

Patients with mild, infrequent asthma symptoms may require only intermittent, asneeded use of an inhaled short-acting beta2-adrenergic agonist. Use of a short-acting beta2-agonist more than twice weekly, other than for exercise-induced bronchospasm, indicates a need for anti-inflammatory treatment. Inhaled corticosteroids are the most effective anti-inflammatory medication; leukotriene modifiers are less effective alternatives. If regular use of an inhaled corticosteroid in a low dose does not prevent symptoms, a long-acting beta2-agonist should be added; addition of a second drug is more effective than raising the dose of the inhaled steroid. A leukotriene modifier can also be used as the second drug. Omalizumab may be considered as adjunctive therapy for patients more than 12 years old who have allergic asthma not controlled by other drugs. A short course of oral corticosteroids may be useful for acute exacerbations. Treatment of acute severe asthma as a medical emergency is not included here; it has been reviewed elsewhere (ER McFadden Jr, Am J Respir Crit Care Med 2003; 168:740).

Allergic rhinitis, allergic conjunctivitis, atopic dermatitis, urticaria and anaphylaxis, along with asthma (reviewed in Treatment Guidelines 2002; 1:7 and not included here), have increased in prevalence during the past 30 years and are now epidemic worldwide, especially in industrialized countries. Many safe and effective drugs are currently available for prevention and relief of symptoms in these disorders, but pharmacological treatment alone may not be sufficient. Patients should also be instructed to avoid specific allergens or environmental conditions that trigger their symptoms. Allergen-specific immunotherapy, parenteral administration of gradually increasing doses of the allergen ("allergy shots"), has been effective in allergic rhinitis, allergic conjunctivitis and allergic asthma, and also in prevention of anaphylaxis triggered by stings from bees, yellow jackets, hornets and wasps. It has not been effective in food allergy, atopic dermatitis or urticaria.

Montelukast (Singulair - Merck), a leukotriene receptor antagonist already marketed for asthma (Treatment Guidelines from The Medical Letter 2002; 1:11), has been approved by the FDA for treatment of seasonal allergic rhinitis in adults and children more than 2 years old.

New drug formulations continue to be introduced for the treatment of asthma, and new studies on older drugs continue to change our perspectives on the management of this chronic inflammatory disease. Treatment of asthma in the emergency department or hospital is not addressed here. More information on the diagnosis and treatment of asthma is available from Expert Panel Report 2: Guidelines for the Diagnosis and Management of Asthma (Bethesda:NIH, 1997 and 2002 update; www.nhlbi.nih.gov).

Fluticasone propionate, an inhaled corticosteroid, and salmeterol xinafoate, a long-acting beta2-adrenergic agonist, are now available together in a dry-powder inhaler for maintenance treatment of patients with asthma. The new combination is not recommended for treatment of acute bronchospasm or for treatment of children less than 12 years old.

Asthma is a chronic inflammatory disorder of the airways; inflammation caused by allergens, viral respiratory infections or other stimuli leads to bronchial hyperresponsiveness and obstruction of airflow. Anti-inflammatory drugs, particularly inhaled corticosteroids, are central to its management.

Asthma is a chronic inflammatory disorder, with inflammation caused by allergens or other stimuli leading to bronchial hyperresponsiveness and obstruction of airflow.

Montelukast sodium (Singulair - Merck), a leukotriene receptor antagonist, has been approved by the US Food and Drug Administration (FDA) for oral prophylaxis and chronic treatment of asthma in adults and children at least 6 years old. It is the third 'leukotriene modifier' to become available in the USA; zafirlukast (Accolate - Medical Letter, 38:111, 1996) and zileuton (Zyflo - Medical Letter, 39:18, 1997) were marketed previously. Neither zafirlukast nor zileuton has been approved by the FDA for use in children less than 12 years old. Leukotriene modifiers are not recommended for treatment of an acute asthma attack (Expert Panel Report 2: Guidelines for the Diagnosis and Management of Asthma, Bethesda: NIH, 1997; www.nhlbi.NIH.gov/nhlbi/lung/ asthma/prof/asthgdln.htm).