R: Respiratory system
Group R holds the drugs for the respiratory system: the nose, the throat and the airways, together with the antihistamines used for allergy.
| Description | In plain terms | Example drug | |
|---|---|---|---|
| R01 | Nasal preparations | Mometasone (R01AD09) / fluticasone furoate (R01AD12), intranasal corticosteroids for allergic rhinitis; xylometazoline (R01AA07) for short-term decongestion | |
| R02 | Throat preparations | Symptomatic relief only. Benzydamine (R02AX03) is the best-supported topical analgesic, chlorhexidine (R02AA05) the common antiseptic lozenge | |
| R03 | Drugs for obstructive airway diseases | asthma and COPD inhalers | Budesonide with formoterol (R03AK07, listed as “formoterol and budesonide”) / salbutamol (R03AC02) |
| R05 | Cough and cold preparations | No strongly evidenced agent; acetylcysteine (R05CB01) and dextromethorphan (R05DA09) are the most used. Dornase alfa (R05CB13) is a genuine standard, but only in cystic fibrosis | |
| R06 | Antihistamines for systemic use | Cetirizine (R06AE07) / loratadine (R06AX13) | |
| R07 | Other respiratory system products | leftovers: surfactants, cystic-fibrosis drugs, nitric oxide | Ivacaftor, tezacaftor and elexacaftor (R07AX32) for cystic fibrosis; neonatal surfactant sits under natural phospholipids (R07AA02), which covers poractant alfa and beractant with no substance-specific code |
Corticosteroids in the nose and lungs
Corticosteroids appear both as nasal sprays in R01 (R01AD) and as inhaled drugs for asthma and chronic obstructive pulmonary disease (COPD) in R03 (R03BA). For beclometasone dipropionate (R01AD01 nasal, R03BA01 inhaled), part of a nasal or inhaled dose is swallowed and can be absorbed from the gut. In 12 healthy subjects, the bioavailability of its active metabolite was similar after nasal and oral doses, at 44% and 41%. With gut absorption blocked by activated charcoal, it was below 1% after a nasal dose and 36% after inhalation. Absorption through the nose itself was therefore insignificant [1].
In a meta-analysis, too little cortisol from the adrenal glands (adrenal insufficiency) was found in 4.2% of patients using nasal corticosteroids (95% CI 0.5 to 28.9%) and in 6.8% of asthma patients using only inhaled corticosteroids [2]. Delivery to the lung is covered under R03.