PHARMACODYNAMICS

Question 1

dopamine hypothesis

biogenic amine hypothesis

Answer 1

dop- psychosis caused by dopamine overactivity in mesolimbic system

biogenic amine- seretonin is the biogenic amine neurotransmitter associated with depression- downregulation or decreased sensitivity of B-adrenergic receptors

Question 2

glutamatergic hypothesis

Answer 2

NMDA receptor antagonists (e.g ketamine and PCP) induce bot +ve and -ve symptoms of schizophrenia in healthy volunteers

Question 3

4 EPSEs

Answer 3

dystonia - muscle spasm, occulogyric crisis Tx- anticholinergics
Pseudo-parkinsonism- tremor, Tx reduce dose, prescribe antichonlinergic
akathasia - restlessness Tx- reduce dose,
tardive dyskinesia - lip smacking, Tx- reduce dose.

Question 4

best antipsychotic in liver failure?

Answer 4

Amisulpride /sulpiride

Question 5

how does chronic lithium use cause diabetes insipidus?

Answer 5

Interference with the action of ADH on its receptors located in the principal cells of collecting ducts in kidney = inability to concentrate urine –> polyuria and polydipsia.

Question 6

best antidepressant in liver failure?

Answer 6

Sertraline
Citalopram
Paroxetine
Vortioxetine
(best avoid TCA and MAOI)

Question 7

Histamine H1 blockade

Alpha 1 blockade

Muscarinic central M1 blockade

Muscarinic peripheral M1 blockade

Answer 7

H block- Weight gain, sedation

Alpha 1 blockade - Orthostatic hypotension, sedation, sexual dysfunction, priapism

Muscarinic central M1 blockade - Agitation, delirium, memory impairment, confusion, seizures

Muscarinic peripheral M1 blockade - Dry mouth, ataxia, blurred vision, narrow angle glaucoma, constipation, urinary retention, tachycardia