Salmeterol
A long-acting beta-2 agonist for COPD and, only alongside an inhaled corticosteroid, for asthma; it is not a reliever.
Drug card
- How it works
- Activating airway beta-2 receptors for long-lasting bronchodilation
- Used for
- Asthma, added to an inhaled corticosteroid
- Preventing exercise-induced bronchospasm
- Maintenance treatment of COPD
- Known for
- Asthma-related death when used without a steroid
- Its name
- -terol means a beta-2 agonist bronchodilator
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does salmeterol work?
A highly selective beta-2 agonist, at least 50 times more selective than salbutamol. Its head sits in the receptor's active site while a long lipophilic side chain binds a nearby 'exosite', so it keeps re-engaging the receptor and acts for many hours. It also strongly inhibits release of histamine and leukotrienes from lung mast cells.
Like other long-acting beta-2 agonists: LABAs stimulate the same airway beta-2 receptors as the short-acting drugs: cyclic AMP rises, bronchial smooth muscle relaxes and mast cells release fewer mediators. They stay active far longer, so they are inhaled twice a day to keep the airways open. In asthma they are given only with an inhaled corticosteroid, because a LABA alone raised the risk of asthma-related death.
Uses
What is salmeterol used for?
- Asthma, added to an inhaled corticosteroid
- Preventing exercise-induced bronchospasm
- Maintenance treatment of COPD
Side effects
Side effects of salmeterol
- Asthma-related death when used without a steroidKnown forSerious
- Headache
- Nasal and sinus congestion
- Cough and throat irritation
- Shaky hands (tremor)
- Palpitations and fast heartbeat
- Muscle and joint pain
- Low potassium (hypokalemia)Serious
- Raised blood sugar
- Arrhythmias and ECG changesSerious
- Paradoxical bronchospasmSerious
- Allergic reactions, including to milk proteinSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Contraindicated in asthma without an inhaled corticosteroid; children and teenagers should get a combined inhaler.
- It cannot treat an acute attack or status asthmaticus; a short-acting reliever is needed for those.
- Strong CYP3A4 inhibitors such as ritonavir and ketoconazole raise its levels and its heart effects.
- Severe milk-protein allergy rules out the dry-powder inhaler.
Good to know: Its exosite anchoring makes it a twice-daily maintenance drug; unlike formoterol it is never used as a reliever.
Remember it
A way to remember it
A LABA never goes out alone in asthma.
On its own a LABA raised asthma-related deaths; given in the same inhaler as an inhaled corticosteroid, large trials found no such rise.
Written for biofideX
Its name
-terol means beta-2 agonist bronchodilator
Salmeterol and formoterol are long-acting beta-2 agonists. Salbutamol and terbutaline lack the stem, though salbutamol's US name, albuterol, has it.
- Every drug name stem
Its class
Long-acting beta-2 agonists
Other long-acting beta-2 agonists with a card:
Easily mixed up with short-acting beta-2 agonists, inhaled antimuscarinics and inhaled corticosteroids.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Salmeterol xinafoate inhalation powder: label (DailyMed)
- Salmeterol (NCI Thesaurus)
- Budesonide inhalers (NHS)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Lungs and allergy
Salmeterol is one of 16 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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