Albuterol is a racemic mixture of the r-isomer levalbuterol and s-albuterol, a short-acting sympathomimetic agent with bronchodilator activity. Albuterol stimulates beta-2 adrenergic receptors in the lungs, thereby activating the enzyme adenylate cyclase that catalyzes the conversion of adenosine triphosphate (ATP) to cyclic-3′,5′-adenosine monophosphate (cAMP). Increased cAMP concentrations relax the bronchial smooth muscle, relieve bronchospasms, and reduce inflammatory cell mediator release, especially from mast cells. Albuterol although to a lesser extent, also stimulates beta-1 adrenergic receptors, thereby increasing the force and rate of myocardial contraction.
Albuterol or salbutamol is a medication that opens up the medium and large airways in the lungs. It is used to treat asthma including asthma attacks, exercise-induced bronchoconstriction, and chronic obstructive pulmonary disease (COPD). It may also be used to treat high blood potassium levels. Salbutamol is usually used with an inhaler or nebulizer but is also available as a pill and intravenous solution. The onset of action of the inhaled version is typically within 15 minutes and lasts for two to six hours.
Mechanism of Action of Albuterol
Albuterol is a beta(2)-adrenergic agonist and thus it stimulates beta(2)-adrenergic receptors. Binding of albuterol to beta(2)-receptors in the lungs results in relaxation of bronchial smooth muscles. It is believed that salbutamol increases cAMP production by activating adenylate cyclase, and the actions of salbutamol are mediated by cAMP. Increased intracellular cyclic AMP increases the activity of cAMP-dependent protein kinase A, which inhibits the phosphorylation of myosin and lowers intracellular calcium concentrations. A lowered intracellular calcium concentration leads to a smooth muscle relaxation and bronchodilation. In addition to bronchodilation, salbutamol inhibits the release of bronchoconstricting agents from mast cells, inhibits microvascular leakage, and enhances mucociliary clearance.
Indications of Albuterol
- Bronchospasm
- Exercise-Induced Bronchoconstriction (EIB)
- COPD,
- Asthma,
- Asthma, acute
- Bronchiectasis
- Bronchospasm Prophylaxis
- Hyperkalemia
- Bronchial asthma,
- Chronic bronchitis,
- Chronic bronchopulmonary disorders
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For symptomatic relief and prevention of bronchospasm due to bronchial asthma, chronic bronchitis, and other chronic bronchopulmonary disorders such as COPD.
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Symptomatic treatment of reversible bronchoconstriction due to bronchial asthma and chronic obstructive pulmonary disease (COPD) including chronic bronchitis and emphysema. Prophylaxis of exercise and allergen-induced asthma.
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Symptomatic treatment of reversible bronchoconstriction due to bronchial asthma and chronic obstructive pulmonary disease (COPD) including chronic bronchitis and emphysema.
Prophylaxis of exercise and allergen-induced asthma.
Contra-Indications of Albuterol
- overactive thyroid gland
- Diabetes
- Ketoacidosis
- Excess Body Acid
- low amount of potassium in the blood
- high blood pressure
- Diminished Blood Flow through Arteries of the Heart
- Disease of Inadequate Blood Flow to the Heart Muscle
- prolonged QT interval on EKG
- abnormal heart rhythm
- Abnormal EKG with QT changes from Birth
- seizures
- Paradoxical Bronchospasm
Dosage of Albuterol
Strengths: 2 mg; 4 mg; 2 mg/5 mL; 90 mcg/inh; 5 mg/mL; 2.5 mg/3 mL
Chronic Obstructive Pulmonary Disease – Acute
Intravenous infusion solution
- Dilute 5 mL of this drug (1000 mcg/mL) in 500 mL of Sodium Chloride Injection, or Sodium Chloride and Dextrose.
- Infusion rates can be started at 5 mcg/min and can be increased to 10 mcg/min and 20 mcg/min at 15 at 30-minute intervals, if necessary.
Nebulizer inhalation solution
- 2.5 mg three or four times a day by nebulization, over approximately 5 to 15 minutes.
Asthma – Acute
Intravenous infusion solution
- Dilute 5 mL of this drug (1000 mcg/mL) in 500 mL of Sodium Chloride Injection, or Sodium Chloride and Dextrose.
- Infusion rates can be started at 5 mcg/min and can be increased to 10 mcg/min and 20 mcg/min at 15 at 30-minute intervals, if necessary.
Nebulizer inhalation solution
- 2.5 mg three or four times a day by nebulization, over approximately 5 to 15 minutes.
Bronchitis
Intravenous infusion solution
- Dilute 5 mL of this drug (1000 mcg/mL) in 500 mL of Sodium Chloride Injection, or Sodium Chloride and Dextrose.
- Infusion rates can be started at 5 mcg/min and can be increased to 10 mcg/min and 20 mcg/min at 15 at 30-minute intervals, if necessary.
Nebulizer inhalation solution
- 2.5 mg three or four times a day by nebulization, over approximately 5 to 15 minutes.
Pediatric Dose for Asthma
Inhalation powder and capsules
- Less than 4 years: Not indicated
4 years or older
- Inhalation powder: 1 or 2 inhalations (90 or 180 mcg) orally every 4 to 6 hours
- Inhalation capsules:1 inhalation (200 mcg) orally every 4 to 6 hours. The total daily dose should not exceed 4 inhalations (800 mcg).
Nebulizer inhalation solution
- Less than 2 years: Not indicated
2 to 12 years
- Less than 15 kg: 0.1 to 0.15 mg/kg/dose (one 3 mL unit-dose vial of 1.25 mg or 0.63 mg inhalation solution) by nebulization. The appropriate volume of the 0.5% inhalation solution should be diluted in sterile normal saline solution to a total of 3 mL prior administration. Dosing should not exceed 2.5 mg three to four times daily.
- 15 kg or more: 2.5 mg (one 3 mL unit-dose vial of 0.0083%) three or four times a day by nebulization, over approximately 5 to 15 minutes. The 0.5% inhalation solution should be diluted with 2.5 mL of sterile normal saline solution
13 years or older
- Inhalation solution 0.5% (5 mg/mL): 2.5 mg (0.5 mL diluted with 2.5 mL of sterile saline solution) three or four times a day by nebulization, over approximately 5 to 15 minutes.
Oral Tablets
- Less than 6 years: Not indicated
6 to 12 years
- Immediate-release tablets: Initial dose: 2 mg orally three or four times a day. Dosage may be cautiously increased stepwise, but not to exceed 24 mg/day (given in divided doses).
- Extended-release tablets: Initial dose: 4 mg orally every 12 hours. Dosage may be cautiously increased stepwise under the control of the supervising physician to a maximum of 24 mg/day in divided doses (e.g., every 12 hours).
13 years or older
- Immediate-release tablets: Initial dose: 2 mg or 4 mg orally three or four times a day. Dosage may be cautiously increased stepwise up to a maximum of 8 mg four times a day as tolerated (maximum of 32 mg/day).
- Extended-release tablets: Initial dose: 4 mg or 8 mg orally every 12 hours. Dosage may be cautiously increased stepwise under the control of the supervising physician to a maximum of 32 mg/day in divided doses (e.g., every 12 hours).
Oral syrup
- Less than 2 years: Not indicated
- 2 to 5 years: Initial dose: 0.1 mg/kg (do not exceed 2 mg) orally three times a day. Dosage may be increased stepwise to 0.2 mg/kg three times a day. A maximum dose of 4 mg three times a day should not be exceeded.
- 6 to 14 years: Initial dose: 2 mg orally three or four times a day. Dosage may be cautiously increased stepwise, but not exceed 24 mg/day (in divided doses).
- 15 years or older: Initial dose: 2 mg or 4 mg orally three or four times a day. Dosage may be cautiously increased stepwise up to a maximum of 8 mg four times a day as tolerated.
Pediatric Dose for Bronchitis
Inhalation powder and capsules
- Less than 4 years: Not indicated
4 years or older
- Inhalation powder: 1 or 2 inhalations (90 or 180 mcg) orally every 4 to 6 hours
- Inhalation capsules:1 inhalation (200 mcg) orally every 4 to 6 hours. The total daily dose should not exceed 4 inhalations (800 mcg).
Nebulizer inhalation solution
- Less than 2 years: Not indicated
2 to 12 years
- Less than 15 kg: 0.1 to 0.15 mg/kg/dose (one 3 mL unit-dose vial of 1.25 mg or 0.63 mg inhalation solution) by nebulization. The appropriate volume of the 0.5% inhalation solution should be diluted in sterile normal saline solution to a total of 3 mL prior administration. Dosing should not exceed 2.5 mg three to four times daily.
- 15 kg or more: 2.5 mg (one 3 mL unit-dose vial of 0.0083%) three or four times a day by nebulization, over approximately 5 to 15 minutes. The 0.5% inhalation solution should be diluted with 2.5 mL of sterile normal saline solution.
13 years or older
- Inhalation solution 0.5% (5 mg/mL): 2.5 mg (0.5 mL diluted with 2.5 mL of sterile saline solution) three or four times a day by nebulization, over approximately 5 to 15 minutes
Side Effects of Albuterol
The most common
- Shakiness in the legs, arms, hands, or feet
- trembling or shaking of the hands or feet
- stomach pain or cramping
- diarrhea
- a headache
- dizziness
- confusion
- stomach pain;
- back pain, joint or muscle pain.
- problems with your vision (including color vision);
- sudden chest pain or trouble breathing;
- pain or swelling in one or both legs;
- a migraine headache;
- pale skin, feeling light-headed or short of breath, rapid heart rate, trouble concentrating; or
- feeling like you might pass out.
More common
- Abdominal or stomach pain, discomfort, or tenderness
- chills or fever
- difficulty with moving
- a headache, severe and throbbing
- joint or back pain
- muscle aching or cramping
- muscle pains or stiffness
- chest pressure or squeezing pain in the chest
- discomfort in arms, shoulders, neck or upper back
- excessive sweating
- feeling of heaviness, pain, warmth and/or swelling in a leg or in the pelvis
- sudden tingling or coldness in an arm or leg
- sudden slow or difficult speech
- sudden drowsiness or need to sleep
- fast breathing
- sharp pain when taking a deep breath
- fast or slow heartbeat
- coughing up blood
- rust colored urine
- decreased amount of urine
Rare
- Anxiety
- change in vision
- chest pain or tightness
- confusion
- a cough
- Agitation
- arm, back, or jaw pain
- blurred vision
- chest pain or discomfort
- convulsions
- extra heartbeats
- fainting
- hallucinations
- a headache
- irritability
- lightheadedness
- mood or mental changes
- muscle pain or cramps
- muscle spasm or jerking of all extremities
- nervousness
Drug Interactions of Albuterol
Albuterol may interact with the following drugs, supplements & may change the efficacy of drugs
- aminophylline
- atomoxetine
- beta-blockers (e.g., propranolol, labetalol, )
- carvedilol
- certain diuretics (e.g., hydrochlorothiazide, furosemide)
- dextroamphetamine
- dipivefrine
- dobutamine
- methylphenidate
- monoamine oxidase inhibitors (e.g., phenelzine, tranylcypromine, moclobemide, selegiline)
- nabilone
- naphazoline
- norepinephrine
- other bronchodilators (e.g., salmeterol, terbutaline)
- oxymetazoline
- phenylephrine
- pseudoephedrine
- theophylline
- tricyclic antidepressants (e.g., amitriptyline, desipramine, nortriptyline)
Pregnancy Catagory of Albuterol
FDA Pregnancy Category C
Pregnancy
Salbutamol is a pregnancy category C drug. It should be used during pregnancy only if absolutely essential. During pregnancy, inhalation of salbutamol has the particular advantage as the therapeutic action can be achieved without the requirement for such plasma concentration liable to have an effect on the fetus.
Lactation
Salbutamol is probably excreted in human milk but the concentration is unknown. However, no adverse effects have been reported in the breastfed babies of mothers receiving salbutamol by inhalation.
References
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