Antidepressants . Anxiolytic . Anti - maniac Flashcards
antidepressant effect sets in after
- 2-4 weeks of treatment.
- Not all manifestations of depression respond equally promptly to treatment with antidepressants.
- Abulia is the manifestation of depression that responds promptly to antidepressant treatment, increases the patient’s capacity for initiative, a situation that can increase the risk of suicide in the first
weeks of treatment. - Progressively, the patient’s thymic condition improves, the suffering and the manifestations related to it disappear, the psychomotor activity increases and the patient’s ability to communicate with those around him.
- Delusional ideas respond a little harder to
antidepressant treatment
Antidepressant drugs can have other psychopharmacological effects:
sedative and anxiolytic
or psychostimulant and anxiogenic
pharmacodynamics of antidepressants
- The mechanism of action of antidepressant drugs is not sufficiently known.
- Increases the availability of neurotransmitters in the synaptic cleft, such as serotonin, norepinephrine, or dopamine, either by preventing their reuptake or by preventing their metabolism.
- Also, antidepressants could block :
1 ) muscarinic receptors,
2) α-adrenergic receptors
3) H1-type histaminergic receptors.
Some of the antidepressant drugs, called atypical, may work by blocking presynaptic serotonergic or noradrenergic receptors.
Pharmacokynetics of antidepressants
1) It is generally well absorbed from the digestive tract. 2) The binding to plasma proteins is made in a large proportion, of approx. 90%, and the distribution is
generally wide.
3) Elimination from the body is predominantly by hepatic metabolism.
4) The half-life is generally long, 20-80 hours, which allows a single administration for 24 hours.
Indications of Antidepressants
- major depression and depression from bipolar psychotic disorders.
- Other indications: phobias
(social phobia and school phobia of children with ADHD), - treatment of enuresis, some chronic pain, probably those involving a lot of an
affective component, treatment of cenestopathies and psychosomatic diseases.
Side effects of Antidepressants
- increased risk of suicide and hypomania.
- Other side effects:
tremor,
speech disorders,
seizures,
decreased or increased psychomotor activity, anxiogenic effects,
memory impairment, parasympatholytic
(constipation, risk of bladder in patients with prostate adenoma, dry mouth, blurred vision, worsening glaucoma),
α-adrenolytic or sympathomimetic side effects (orthostatic hypotension and arrhythmias)
Tricyclic antidepressants (TCA)
- work by inhibiting noradrenaline transporter (NET)
and serotonin transporter (SERT), - inhibiting dopamine reuptake and have parasympatholytic, α- adrenolytic and antihistamine H1 effects.
- Some are of the sedative type, such as
amitriptyline,
trimipramine and
doxepine, which produce sedation and anxiolytic effects,
and others are of the psychotonic type, such as
protriptyline, desipramine and clomipramine,
causing increased alertness and anxiety. The antidepressant effect sets in after 2-4 weeks of
treatment.
Selective serotonin reuptake inhibitors (SSRIs)
- inhibit serotonin reuptake,
without inhibiting noradrenaline reuptake,
and without antimuscarinic, α-adrenolytic or
antihistamine H1 effects.
Such are drugs such as
fluoxetine,
sertraline,
paroxetine,
fluvoxamine,
citalopram,
escitalopram. The effectiveness is comparable to that of tricyclic antidepressants.
DIGESTIVE FFECTS -
nausea, diarrhea, vomiting, insomnia, anxiety,
irritability, sexual dysfunction.
Abrupt discontinuation of serotonin reuptake inhibitors may cause withdrawal syndrome with tremor, headache, nausea, nervousness, insomnia.
Serotonin and norepinephrine reuptake inhibitors (SNRIs)
- inhibit the activity of the
transporter for noradrenaline (NET) and serotonin (SERT), - but have NO :
antimuscarinic,
α adrenergic blockers,
or H1 receptor blockers - venlafaxine, desvenlafaxine, duloxetine.
Serotonin and norepinephrine reuptake antidepressants are probably as effective as tricyclic
antidepressants, but better tolerated by the patient.
ADVERSE EFFECTS
Nausea, headache, sleep problems and sexual dysfunction. Not given with MAOIs (induces serotonin
syndrome - > Hyperthermia , muscle rigidity ,CV collapse )
Increased risk of suicide in young patients. Overdose causes CNS depression, seizures,
cardiac dysrhythmias.
Atypical antidepressants
- have an antidepressant effect comparable to other antidepressant drugs, but have very few sympathomimetic side effects (tachycardia, arrhythmias) or parasympatholytic.
Mianserin - blocks α2-presynaptic receptors to facilitate synaptic transmission.
Nefazodone - inhibits :
1) 5-HT1A type presynaptic serotonergic receptors and 2) 5- HT2 receptor serotonin receptors,
3) especially 5-HT2A, as well as atypical antipsychotic drugs (quetiapine).
Bupropion - inhibits NET, SERT but also DAT (dopamine transporter)
as well as VMAT2 (transporter associated with monoamine storage vesicles) and
- increases the release of noradrenaline and dopamine in the synaptic clefts.
Bupropion is combined with another antidepressant if after 8 weeks of treatment.
Monoamine oxidase inhibitors (MAOIs).
The antidepressant effect of these drugs is probably of the same intensity as that of tricyclic antidepressants and is installed with the same latency of 2-4 weeks as in the case of tricyclic antidepressants. Side effects: hypotension, hypertensive attacks, liver damage, polyneuritis, agitation, hyperreflexia, delirium, seizures.
monoamine oxidase A (MAO A),
specific for serotonin and norepinephrine
monoamine oxidase B (MAO B)
specific for dopamine and norepinephrine
Phenelzine and tranylcypromine
irreversibly and nonselectively inhibit MAO and have antidepressant effect.
Chlorgillin and moclobemide
specific inhibitory antidepressants for monoamine oxidase A,
better tolerated than nonspecific monoamine oxidase inhibitors