PSEUDOEPHEDRINE HCL
DESCRIPTION
Pseudoephedrine sulfate, a sympathomimetic amine, is a salt of pseudoephedrine,
one of the naturally occurring alkaloids obtained from various species of the
plant EPHEDRA. The empirical formula for pseudoephedrine sulfate is
(C10H15NO)2*H2SO4; the chemical name is Benzenemethanol, (alpha)-(1-
(methylamino)ethyl)-, (S-(R*, R* ) )-, sulfate (2:1) (salt).
The molecular weight of pseudoephedrine sulfate is 428.56. It is a white to off-
white crystal or powder, very soluble in water, freely soluble in alcohol, and
sparingly soluble in chloroform.
Pseudoephedrine sulfate (d-isoephedrine sulfate) is an orally effective nasal
decongestant which appears to exert its sympathomimetic effect indirectly,
predominantly through release of adrenergic mediators from post-ganglionic nerve
terminals. In effective recommended oral dosage, pseudoephedrine sulfate
produces minimal other sympathomimetic effects, such as pressor activity and CNS
stimulation. Use of an orally administered vasoconstrictor for shrinkage of
congested nasal mucosa has several advantages: a) it produces a gradual but
sustained decongestant effect, causing little, if any "rebound" congestion; b)
it facilitates shrinkage of swollen mucosa in upper respiratory areas that are
relatively inaccessible to topically applied sprays or drops; c) it relieves
nasal obstruction without the additional irritation that may result from local
medication.
Pseudoephedrine passes through the blood-brain and placental barriers. While the
antihistamines have not been studied systematically for passage through these
barriers, the occurrence of pharmacologic effects in the central nervous system
and in newborns indicate presence of the drug.
PRECAUTIONS:-
Increased ectopic pacemaker activity can occur when pseudoephedrine is used concomitantly with digitalis.Antacids increase the rate of absorption of pseudoephedrine, while kaolin decreases it. The In Vitro addition of pseudoephedrine to sera containing the cardiac isoenzyme MB of serum creatine phosphokinase progressively inhibits the activity of the enzyme. The inhibition becomes complete over 6 hours.
Pseudoephedrine, like other central nervous system stimulants, has been abused.
At high doses, subjects commonly experience an elevation of mood, a sense of
increased energy and alertness, and decreased appetite. Some individuals become
anxious, irritable, and loquacious. In addition to the marked euphoria, the user
experiences a sense of markedly enhanced physical strength and mental capacity.
With continued use, tolerance develops, the user increases the dose, and toxic
signs and symptoms appear. Depression may follow rapid withdrawal.
OVERDOSAGE:
In the event of overdosage, emergency treatment should be started immediately.
Manifestations of overdosage may vary from central nervous system depression
(sedation, apnea, diminished mental alertness, cyanosis, coma, cardiovascular
collapse) to stimulation (insomnia, hallucinations, tremors, or convulsions) to
death. Other signs and symptoms may be euphoria, excitement, tachycardia,
palpitations, thirst, perspiration, nausea, dizziness, tinnitus, ataxia, blurred
vision, and hypertension or hypotension. Stimulation is particularly likely in
children, as are atropine- like signs and symptoms (dry mouth; fixed, dilated
pupils; flushing; hyperthermia; and gastrointestinal symptoms).
In large doses sympathomimetics may give rise to giddiness, headache, nausea,
vomiting, sweating, thirst, tachycardia, precordial pain, palpitations,
difficulty in micturition, muscular weakness and tenseness, anxiety,
restlessness, and insomnia. Many patients can present a toxic psychosis with
delusions and hallucinations. Some may develop cardiac arrhythmias, circulatory
collapse, convulsions, coma, and respiratory failure.
The oral LD50 of the mixture of the two drugs in mature rats and mice was
greater than 1700 mg/kg and 600 mg/kg, respectively.
TREATMENT -The patient should be induced to vomit, even if emesis has occurred
spontaneously. Pharmacologically induced vomiting by the administration of
ipecac syrup is a preferred method. However, vomiting should not be induced in
patients with impaired consciousness. The action of ipecac is facilitated by
physical activity and by the administration of eight to twelve fluid ounces of
water. If emesis does not occur within 15 minutes, the dose of ipecac should be
repeated. Precautions against aspiration must be taken, especially in infants
and children. Following emesis, any drug remaining in the stomach may be
adsorbed by activated charcoal administered as a slurry with water. If vomiting
is unsuccessful or contraindicated, gastric lavage should be performed. Isotonic
and one-half isotonic saline are the lavage solutions of choice. Saline
cathartics, such as milk of magnesia, draw water into the bowel by osmosis and
therefore may be valuable for their action in rapid dilution of bowel content.
Dialysis is of little value in antihistamine poisoning. After emergency
treatment the patient should continue to be medically monitored.
Treatment of the signs and symptoms of overdosage is symptomatic and supportive.
Stimulants (analeptic agents) should NOT be used. Vasopressors may be used to
treat hypotension. Short-acting barbiturates, diazepam, or paraldehyde, may be
administered to control seizures. Hyperpyrexia, especially in children, may
require treatment with tepid water sponge baths or a hypothermic blanket. Apnea
is treated with ventilatory support.