BRAND NAME: ELAVIL
AVAILABLE IN
10 mg, 25 mg, 50 mg,
75 mg, 100 mg & 150 mg
TABLETS
BACKGROUND
Amitriptyline was developed out of a need in human medicine for
anti-anxiety medications in the treatment of mental illness though,
in humans, it has gained some popularity for the treatment of chronic
pain syndromes, especially interstitial cystitis.
This medication creates its effects via several mechanisms:
By blocking the way cells of the nervous system transport biochemicals
called “amines,” amitriptyline is able to increase the levels of
circulating neurotransmitters, especially a neurotransmitter called
“serotonin.” This mechanism seems to be at the route of amitriptyline’s
anti-anxiety and psychoactive properties. In humans, this medication
is used in the treatment of anxiety, bipolar disorders, and depression.
This property also is responsible for amitriptyline’s sedation side
effect.
The same blockage of the amine pump leads to increased levels of
the neurotransmitter “norepinephrine.” Norepinephrine is an important
neurotransmitter in the “sympathetic ” nervous system as described
below.
Amitriptyline is a strong antihistamine.
Amitryptiline also has what are called “anticholinergic” effects
which requires some explanation. The part of the nervous system
which regulates an assortment of involuntary operations is called
the “autonomic nervous system.” It is divided into two areas: the
“sympathetic” system which is responsible for generating changes
during a “fight or flight situation” (such changes include increased
circulation to muscles, increased heart rate, pupil dilation etc.)
and the “parasympathetic” nervous system which is responsible for
maintaining the body’s “status quo.” The parasympathetic system
uses “acetylcholine” as its chief neurotransmitter. An anticholinergic
medication, disrupts acetylcholine and creates side effects such
as dry mouth, urinary retention, constipation, dried respiratory
secretions.
Amitriptyline is a member of the class of drugs called “tricyclic
antidepressants.”
HOW THIS DRUG IS USED
With amitriptyline becoming widely used in human mental illness,
itt was not long before small animal uses for this medication came
to light. Amitriptyline has been used in animals for separation anxiety,
for inappropriate urination in cats, for feline lower urinary tract
disease in cats, and for obsessive grooming behaviors in both dogs
and cats. In many of these conditions it is not clear which of the
above described mechanisms of action are responsible for the desired
effects.
SIDE EFFECTS
The most common side effect is drowsiness/sedation.
Anticholinergic side effects would probably not be surprising: dry
mouth (manifested in animals often as frequently licking of the lips),
urinary retention, constipation.
The most potentially dangerous side effect that happens with a realistic
frequency is the exacerbation of a cardiac rhythm disturbance. For
this reason, an EKG screening has been recommended before starting
this medication.
Tricyclic antidepressants can alter blood sugar levels.
In humans, side effects in virtually every organ system have been
reported at one time or another which means that potentially any
side effect could be attributed to the use of this medication.
INTERACTIONS WITH OTHER MEDICATIONS
Tricyclic antidepressants such as amitriptyline cannot be safely
used with monoamine oxidase inhibitors such as Deprenyl (Anipryl®).
The risk developing a dangerously low white blood cell count with
the use of methimazole is greatly increased if there is concurrent
use of amitriptilline.
The use of Cimetadine (Tagamet®) can interfere with the desired
effect of amitriptyline.
Amitriptyline is best not used in conjunction with other drugs with
anticholinergic effects, drugs that stimulate the sympathetic nervous
system, or with other psychoactive drugs.
CONCERNS AND CAUTIONS
Amitriptyline is removed from the body via the liver. Patients with
abnormal liver function may have trouble with this medication. Periodic
liver enzyme evaluation (blood testing) is a good idea for patients
on this medication long term.
Amitriptyline should not be used in pregnancy or lactation, in patients
with seizure disorders, or in patients with cardiac rhythm disturbances.
Diabetic pets should avoid the use of amitriptyline.
Amitriptyline Medical Center Amitriptyline
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