Appetite Stimulants Chemische Eigenschaften,Einsatz,Produktion Methoden
Chemische Eigenschaften
The analeptic stimulants are a diverse chemical class of
agents ranging from plant alkaloids, such as picrotoxin
and strychnine, to synthetic compounds, such as
pentylenetetrazol and doxapram. The wide range of
chemical structures makes this particular class somewhat
difficult to categorize with respect to absorption,
distribution, and metabolism. However, most analeptic
stimulants can be absorbed orally and have short durations
of action. The pharmacological effect of most of
these compounds is terminated through hepatic metabolism
rather than renal excretion of unchanged drug.
Clinical Use
As indicated, most of the analeptic stimulants were
used as pharmacological treatments for overdosage of
CNS depressants. Doxapram (Dopram) is sometimes
used to counteract postanesthetic respiratory depression
and as an aid in chronic obstructive pulmonary disease.
Pentylenetetrazol (Metrazol) was used experimentally
on rare occasions to “activate” the electroencephalogram.
Strychnine is used almost exclusively in animal
studies as a tool for studying CNS mechanisms because
it is a relatively specific glycine antagonist.
Nebenwirkungen
Most of the CNS stimulants produce adverse reactions
that are extensions of their therapeutic effect. These coma and death. Convulsions produced by this class of
agents (with the exception of strychnine) are usually
tonic–clonic and are uncoordinated. In some cases, the
convulsions are preceded by marked stimulation of respiration,
tachycardia, and excessive pressor effects.
The uncontrolled excitation that occurs after accidental
or intentional strychnine ingestion (in the absence
of normal inhibition) results in characteristic convulsions.
In humans, in whom extensor muscles are
normally dominant, tonic extension of the body and all
limbs is observed. This hyperextension is known as
opisthotonos; at its extreme, it consists of a characteristic
posture in which the back is arched and only the
back of the head and the heels are touching the surface
on which the victim is lying. Figure 29.1 illustrates a patient
in opisthotonos. Under the influence of strychnine,
all sensory stimuli produce exaggerated responses. The
primary therapeutic consideration after strychnine poisoning
is to prevent convulsions, which may be fatal.
Diazepam and clonazepam appear to
be moderately effective in preventing strychnine convulsions,
and either of these is the agent of choice.
Barbiturates are often used to treat overdoses of all of
the analeptic stimulants. Generally, however, antidotal
therapy is not required.
Appetite Stimulants Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte