Salbutamol
Salbutamol (INN) or
albuterol (USAN) is a short-acting β2-adrenergic receptor agonist used for
the relief of bronchospasm in conditions such as asthma and COPD.
Salbutamol sulfate is usually given by the inhaled route for
direct effect on bronchial smooth muscle. This is usually achieved through a
metered dose inhaler (MDI), nebuliser or other proprietary delivery devices
(eg. Rotahaler or Autohaler). Salbutamol can also be given orally or
intravenously. However, some asthmatics may not respond to these medications as
they will not have the required DNA base sequence in a specific gene.
Salbutamol became available in the United Kingdom in 1969 and in the United States
in 1980 under the trade name Ventolin.
Clinical use
Salbutamol is specifically indicated in the following
conditions:
acute asthma
symptom relief during maintenance therapy of asthma and
other conditions with reversible airways obstruction (including COPD)
protection against exercise-induced asthma
hyperkalemia, especially in patients with renal failure
can be aerosolized for patients with Cystic Fibrosis, along
with ipratropium bromide and pulmozyme.
As a β2-agonist, salbutamol also finds use in
obstetrics. Intravenous salbutamol can be used as a tocolytic to relax the
uterine smooth muscle to delay premature labour. Whilst preferred over agents
such as atosiban and ritodrine, its role has largely been replaced by the
calcium-channel blocker nifedipine which is more effective, better tolerated
and orally administered. (Rossi, 2004)
Mode of action
As with other β2-adrenergic receptor agonists,
salbutamol binds to β2-adrenergic receptors with a higher affinity than
β1-receptors. In the airway, activation of β2-receptors results in
relaxation of bronchial smooth muscle. resulting in a widening of the airway
(bronchodilation). Inhaled salbutamol sulfate has a rapid onset of action,
providing relief within 5-15 minutes of administration.
In tocolysis, the activation of β2-receptors results in
relaxation of uterine smooth muscle, thus delaying labour.
Adverse effects
Whilst salbutamol is well-tolerated, particularly when
compared with previous therapies such as theophylline, like all medications
there exists the potential for adverse drug reactions to occur - especially
when in high doses, or when taken orally or intravenously.
Common adverse effects include: tremor, palpitations and
headache. (Rossi, 2004)
Infrequent adverse effects include: tachycardia, muscle
cramps, agitation, hypokalemia, hyperactivity in children, and insomnia.
(Rossi, 2004)
Other brand names
Salbutamol is sold under the brand names Airomir, Asthalin,
Asmol, Buventol, Proventil, Salamol, Sultanol, Ventolin and Volmax.
Source: wikipedia GFDL
