| | R - Respiratory System |  | Inhaled antiinfectives are classified in ATC group J - Antiinfectives for systemic use.
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| | R03 - Drugs for Obstructive Airway Diseases |  |  | 
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| | R03D - Other Systemic Drugs for Obstructive Airway Diseases |  | Theophyllines are classified in this group. Other respiratory stimulants are classified in R07AB - Respiratory stimulants.Corticosteroids for systemic use, see H02.
 Sympathomimetics for systemic treatment of rhinitis, see R01BA.
 
 |  | This group comprises mainly the xanthines. The DDDs for these substances are based on treatment of obstructive lung diseases.
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| | R03DX - Other Systemic Drugs for Obstructive Airway Diseases |  | This group comprises preparations, which cannot be classified in the preceding groups.Interleukin inhibitors used in asthma are classified in this group.
 
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