PhrmDyn- 20C Flashcards
Definition of pharmacodynamics
effects of drugs on body
Define inhibitor
drug that interferes with the normal function of the NT transporter
Define antagonist
- molecule that has no intrinsic NT effects that blocks any ligand from acting
- it is LITERALLY A BLOCKER, ALL BODY NO BRAIN!!
Define inverse agonist
- causes receptor activity to drop below basal levels
- eg. Nuplazid- Primavansarin- antipsychotic for the treatment of psychosis in Parkinson’s disease
Name the 2 types of antagonists
- competitive
- non-competitive antagonist
Define partial agonist
-molecule with reduced intrinsic activity that mimics that that of NT but at reduced intensity
How do pre-synaptic agonists work
-they increase negative feedback therefore decreasing the release of NT from the terminal
Types of pre-synaptic agonists
- autoreceptors
- hetero-receptors (decrease release of a different terminal NT)
Examples of partial agonists
- buprenorphine
- aripiprazole
- buspirone
Examples of pre-synaptic agonists
- clonidine/guanfacine
- alpha 2 agonism leads to inhibition of release of monoamines
Two types of NT receptor types
- ligand-gated ion channels
- G protein-coupled receptors coupled to second messenger cascade
How do the tryptans work?
- 5HT1D direct receptor agonists
- cause constriction of cranial arteries
How do the SSRIs work?
-block activity of the serotonin transporter
How do SNRI’s work?
-block activity of the serotonin and norepinepherine transporters
How does buproprion work?
-DNRI
blocks activity of the DA and NE transporters
How does mirtazapine work?
- pre-synaptic alpha 2 antagonism (antidepressant)
- post-synaptic alpha 1 antagonism (orthostasis)
- histamine receptor antagonism (weight gain and sedation)
How do the SGAs work?
- D2 receptor blockade
- 5HT2 receptor blockade
How does ziprasidone work?
- D2 receptor blockade
- 5HT2 receptor blockade
- serotonin transporter blockade
How does amphetamine work?
- increased release of NE and DA
- blocks MAOI
- block NE and DA transporters
How do clonidine and guanfacine work?
-decrease monoamine release through increasing alpha-2 negative feedback
How does rivastigmine work?
-blocks AChE and BChE (present on glial cells in CNS)
What are the groups of monoamines?
- Catecholamines
- Tryptamines
- Histamines
Name the cardiac effects of monoamines
-supraventricular tachycardias
(prolonged PR interval)
-ventricular tachycardias
(prolonged QT interval)
Rules of thumb regarding the QTc
- QTc >= 500 mg : 2-3 times increased risk of TdP
- or if increase in QTc of more than 60 ms stop the medication
Normal QTc?
<420 ms
Medications that prolong QTc Interval
- TCAs
- SSRI
- SNRI
- FGA: pimozide (Rx resistant Tourette’s)
- SGA
- Lithium
- Opioids: methadone
Describe Mirtazapine’s anticholinergic effects
-mirtazapine has VERY LOW anticholinergic effects
Which antidepressants have high anticholinergic effects?
- TCA’s
- Paroxetine
- Duloxetine
Precipitating factors for closed angle glaucoma
- sympathomimetics
- anticholinergics (un-opposed sympathetic tone)
- occurs at the angle of Schlemm
What is SIADH?
- too much water retained leading to hyponatremia (Na < 130)
- death rate with hyponatremia increased 60 fold
Some drugs that cause SIADH
- Nicotine
- Carbamazepine
- TCA’s
- SSRI’s
Symptoms of central pontine myelinolysis
- spastic quadraparesis
- pseudobulbar palsy
- delirium
- coma
Hypotension causing medications
- Clonidine and guanfacine
- prazosin
- mirtazapine
- MAOIs
- FGAs and SGAs (Chlorpormazine, Clozapine, Quetiapine
