138 Section 3/ Drugs Acting on ANSORCIPRENALINE
Is a potent β-adrenergic agonist.
Receptor sites in the bronchi and bronchioles
are more sensitive to the drug than those in
the heart and blood vessels.
It decreases reversible bronchospasm
associated with chronic bronchitis,
pulmonary emphysema, bronchial asthma,
silicosis, tuberculosis and sarcoidosis. The
resultant decrease in airway obstruction
may relieve the dyspnea associated with
bronchospasm.
It is effective both by oral route as well
as inhalation.
There is more rapid onset of action
following inhalation administration.
Absorption via the bile is 45 percent of
renal excretion. Bioavailability of the active
substance is 33% owing to a first pass effect.
It is indicated in bronchial asthma and
reversible bronchospasm associated with
chronic bronchitis and pulmonary emphy-
sema, including bronchospasm due to the
use of b-blocking agents.
Can be used as a supportive therapy
with antibiotics, secretomucolytics,
corticosteroids, physiological saline and
disodium chromoglycate.
Side effects such as palpitation, restless-
ness and finger tremor may occur; in iso-
lated cases, flushing, headache, sleep distur-
bances, nausea, ventricular disturbances or
angina pectoris and allergic skin reactions
have been observed.
The injection or infusion of high doses
may also cause tachycardia, arrhythmia and
a decrease in blood pressure.
AMPHETAMINE
It is a synthetic compound with
structural similarity to ephedrine and is
available in racemic and dextro isomers. It
increases the systolic and diastolic blood
pressure. Amphetamine is a potent CNS
stimulant and causes alertness, insomnia,
increased concentration, euphoria or
dysphoria and increased work capacity.
Amphetamine produces wakefulness and
improved physical performance. It contracts
the sphincter of the bladder and relaxes the
bronchial smooth muscle in large doses.
Amphetamines are drugs of abuse and can
produce behavioural abnormalities and can
precipitate psychosis. It can produce
psychological but no physical dependence.
Because of its misuse especially by
teenagers, its use is limited to the treatment
of Attention Deficit Hyperactivity Disorder
(ADHD) and narcolepsy.PHENYLEPHRINE
It is a vasopressor agent with some struc-
tural similarity to adrenaline and has a power-
ful alpha 1 receptor stimulant action. The pres-
sor response is accompanied by reflex brady-
cardia. It is used as a nasal decongestant and
mydriatic agent and also in the treatment of
paroxysmal supraventricular tachycardia.UTERINE RELAXANTS (TOCOLYTICS)
These are the agents which decrease uterine
motility and have been used to delay or postpone
labour and to arrest threatened abortion which
is needed to allow fetus to mature.ISOXSUPRINE
Both nylidrin and isoxsuprine have got
beta receptor stimulant action and is used