Long-acting beta-2 agonists
Activating airway beta-2 receptors for long-lasting bronchodilation.
Also called LABAs.
Class card
- Drugs
- Salmeterol and Formoterol
- Used for
- Asthma, always with an inhaled corticosteroid
- Maintenance treatment of COPD
- Preventing exercise-induced bronchospasm
- Known for
- Asthma-related death when used without a steroid
- Name stems
- -terol
- Part of
- sympathomimetics
3 cards: the class, and each drug in it.
Mechanism of action
How do long-acting beta-2 agonists work?
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.
The drugs
Long-acting beta-2 agonists with a card
Uses
What are long-acting beta-2 agonists used for?
- Asthma, always with an inhaled corticosteroid
- Maintenance treatment of COPD
- Preventing exercise-induced bronchospasm
Side effects
Side effects of long-acting beta-2 agonists
- Asthma-related death when used without a steroidKnown forSerious
- Headache
- Shaky hands (tremor)
- Palpitations and fast heartbeat
- Nervousness and sleeplessness
- Muscle cramps
- Low potassium (hypokalemia)Serious
- Raised blood sugar
- Arrhythmias and ECG changesSerious
- Paradoxical bronchospasmSerious
What the class has in common. Each drug's card has its own, and Known for marks what an exam expects you to know.
Watch for
Cautions
- In asthma a LABA without an inhaled corticosteroid is contraindicated; combined inhalers keep the two together.
- They are not rescue drugs; only formoterol, combined with budesonide, is also used as a reliever.
- Using two LABA-containing inhalers at once risks overdose and dangerous heart effects.
- Beta blockers block their effect; diuretics, steroids and theophylline deepen the fall in potassium.
Remember them
A way to remember them
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
Name stems
-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
Don't mix them up
Classes easily confused with these
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Salmeterol xinafoate inhalation powder: label (DailyMed)
- Formoterol fumarate inhalation solution: 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
Practice long-acting beta-2 agonists with the other classes in this group: what each drug is, how it works, what it treats and what it's known for.
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