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neuroleptic-related extrapyramidal
side effects, but they may be given
prophylactically in high-risk patients.
The anticholinergic agent should
be tapered and discontinued after
one to six months if possible.
Classification of Anticholinergic/Antiparkinsonian Agents
Name Trade Class Dose
Name
Benztropi Cogentin Anticholin 1-2 mg bid-tid orally or 1-2
ne ergic mg IM
Biperiden Akineton Anticholin 2 mg bid-tid orally or 2 mg
ergic IM
Trihexy Artane Anticholin 2-5 mg bid-qid
phenidyl ergic
Diphenhy Benadryl Antihista 25-50 mg bid to qid or 25
dramine mine/ Anti 50 mg IM
cholinergic
Amantadi Symmetrel Dopamine/ 100-150 mg bid
ne Agonist
4. Side Effects of Anticholinergic
Agents
a. The most common side effects
resultfrom peripheral antichoinergic
l
blockade:drymouth,constipation,
blurry vision, urinaryhesitancy,
decreased sweating, increased
heart rate, and ejaculatory
dysfunction.
b. Acentral anticholinergic syndrome
occurs with high doses, or
when the agent is combined
withotheranticholinergic medications.
The syndrome is characterized
by confusion, dry flushed skin,
tachycardia,and pupillarydilation.
In severe cases, delirium,
hallucinations, arrhythmias,
hypotension, seizures, and
coma may develop.
c. Anicholinergic drugsarecontraindicated
t
in narrow angle glaucoma
and should be used cautiously
in prostatic hypertrophy or
cardiovascular disease.
d. Amantadine does not have
anticholinergic side effects;
however, amantadine may
cause nausea,insomnia,decreased
concentration,dizziness, irritability,
anxiety,and ataxia.Amantadine
is contraindicated in renal
failure.
Antidepressants
I. Indications forAntidepressant Medication.
Unipolar and bipolar depression, organic
mood disorders, anxietydisorders (panic
disorder, generalized anxiety disorder,
obsessive-compulsive disorder, social
phobia), schizoaffective disorder, eating
disorder, and impulse control disorders.
II. Classification of Antidepressants
A. Selective-Serotonin (5HT) Reuptake
Inhibitors. Fluoxetine (Prozac),
sertraline (Zoloft), paroxetine (Paxil),
fluvoxamine (Luvox), citalopram
(Celexa), escitalopram (Lexapro).
B. Serotonin/Norepinephrine Reuptake
Inhibitors. Heterocyclics (TCAs),
venlafaxine (Effexor)
C. Norepinephrine/Dopamine Reuptake
Inhibitors. Bupropion (Wellbutrin).
D. MixedSerotonin Reuptake Inhibitor/Serotonin
Receptor Antagonist. Trazodone
(Desyrel), nefazodone (Serzone).
E. Alpha-2 Adrenergic Antagonist.
Mirtazapine (Remeron)
F. Monamine Oxidase (MAO)Inhibitors.
Phenelzine,tranylcypromine,isocarboxazid.
III. Clinical Use of Antidepressants
A. All antidepressants have been shown
to have equivalent efficacy. The
selection of an agent depends on
past history of response, anticipated
tolerance to side effects, and coexisting
medical problems.
B. Once a therapeutic dose is reached,
symptom improvementtypicallyrequires
3 to 6 weeks. TCAs and bupropion
have the narrowest therapeutic index
and presentthegreatestrisk in overdose.
C. If no significant improvement is seen
after an adequate trial (4-6 weeks),
then the dosage should be increased
or one may switch to a medication
in another antidepressant class.
Alternatively, an augmenting agent
such as lithium should be added.
D. When psychoticsymptoms accompany
severe cases ofdepression,concomitant
antipsychotic medication is usually
required and should be discontinued
when the psychosis abates.
E. Patients with three episodes of major
depression should be placed on
long-term maintenance treatment.
IV. Side Effects
A. Cardiac Toxicity
1. Tricyclic antidepressants may
slow cardiac conduction, resulting
in intraventricular conduction delay,
prolongation of the QT interval,
and AVblock.Patients withpreexisting
conduction problemsarepredisposed
to arrhythmias. Therefore, TCAs
should not be used in patients
withconduction defects, arrhythmias,
or a history of a recent MI.
2. SSRIs, venlafaxine, bupropion,
mirtazapine, and nefazodone
have noeffectsoncardiacconduction.
B. Anticholinergic Adverse Drug
Reactions. Dry mouth, blurred vision,
constipation, and urinary retention.
C. Antihistaminergic Adverse Drug
Reactions. Sedation, weight gain.
D. Adverse Drug Reactions Caused
by Alpha-1 Blockade. Orthostatic
hypotension,sedation,sexual dysfunction.
E. Serotonergic Activation.GI symptoms
(nausea,diarrhea),insomnia or somnolence,
agitation, tremor, anorexia, headache,
and sexual dysfunction can occur
withSSRIs,especiallyearlyin treatment.
F. MAO inhibitors. The most common
adverse drug reaction is hypotension.
Patients are also at risk for hypertensive
crisis if foods high in tyramine content
or sympathomimetic drugs areconsumed.
Despite the infrequent use of MAO
inhibitors, they remain very important
forthetreatmentofrefractorydepression.
Commonly Used Antidepressants
Drug Recommended dosage Comments
Secondary Amine Tricyclics
Class as a whole: Side effects include anticholinergic effects (dry mouth, blurred
vision, constipation) and alpha-blocking effects (sedation, orthostatic hypotension,
cardiac rhythm disturbances). May lower seizure threshold.
Desipramine (Norpramin, Initial dosage 25-50 mg qhs, Mayhave CNS stimulant effect;
generics) average dose 150-250 mg/d, best taken in morning to avoid
Mayrequire dose of 300 mg/d. insomnia.
[10, 25, 50, 75, 100, 150 mg]
Protriptyline(Vivactil) Initialdoseof5mgqam increasing Low sedation, avoid bedtime
to 15-40 mg/d in bid dosing dosing.
[5, 10 mg]
Nortriptyline(Pamelor) Initial dose 25 mg qhs, increasing Sedating.
to 75-150 mg/d; monitor levels
to achieve serum level between
50-150 ng/mL. [10, 25, 50,
75 mg]
Tertiary Amine Tricyclics
Class as a whole: Anticholinergic effects and orthostatic hypotension may
be more severe than with secondary amine tricyclics. All are contraindicated
in glaucoma and should be used with caution in urinary retention and cardiovascular
disorders.
Amitriptyline (Elavil, Initial dose of 25-50 mg qhs High sedation.Highanticholinergic
generics) increasing to 150-250 mg/d. activity.
May be given as single hs
dose. [10, 25, 50, 75, 100,
150 mg]
CIomipramine(Anafranil) Initial dose of 25-50 mg qhs Relativelyhigh sedation,anticholinergic
increasing to 150-250 mg/d; activity, and seizure risk.
may be given once qhs [25,
50, 75 mg]
Doxepin (Sinequan, Initial dose of 25-50 mg/d, High sedation, often used
Adapin) increasing to 150-300 mg/d. as a hypnotic at a dosage
[10, 25, 50, 75, 100, 150 mg] of 25-150 mg qhs.
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