What is the big difference between TCAs and second generation antidepressants?
2nd gen are more specific for receptors
- TCAs have a more global effect (bind to cholinergic receptors throughout body)
- 2nd gen have more tolerable side effects and better long term management
What are the types of SSRIs?
- Fluoxetine (Prozac)
- Fluvoxamine (Luvox)
- Sertraline (Zoloft)
- Paroxetine (Paxil)
- Citalopram (Celexa) - purest SSRI
- SSRIs current drug of choice
What are the types of 2nd sen antidepressants?
SSRI
SNRI- Venlafaxine (Effexor)
NERI -Reboxetine
DRI - Bupropion (Wellbutrin, Zyban)
What are ADRs characteristics of TCAs?
- Sedation
- Seizures -Due to increased neurotransmitter activity in brain
- Highest potential for fatal overdose - due to risk of suicide
- Central - delirium/confusion
- Peripheral Anticholinergic effects - Dry mouth; Constipation; Urinary retention; Tachycardia; Arrhythmias; Orthostatic hypotension
ADRs: Tend to produce CNS excitation (Restlessness, Irritability, Agitation, Sleep loss); Some central and peripheral anticholinergic effects; Because of systemic MAO inhibition, excess activity at peripheral adrenergic sympathetic may cause hypertensive crisis (tyramines released)
MAO-I
What can cause serotonin syndrome?
- confusion, shivering, agitation, tremor, fever, ataxia, sweating, diarrhea
- can lead to seizures, coma, arrhythmia, renal failure and death
MAO-I and SSRI drugs
What antidepressant may cause movement disorders?
- Severe restlessness (akathisia)
- Tardive dyskinesia
- Pseudoparkinsonism
- Dystonias
- Dyskinesias
- sexual dysfunction
Second gen
Advantages:
- less sedation, ACh actions, cardiovascular effects
- more GI problems and insomnia
What drug is sometimes used during rehab from stroke?
SSRIs
- Unlikely to hinder treatment
- Mitigate deleterious effects of depression
- Increased energy and motivation
- Improved concentration
- May enhance reparative processes (recovery/ neuroplasticity)
How may SSRIs inhibit rehab?
- Insomnia
- Restlessness
- Agitation
Why might suicide risk increase transiently after any antidepressant is started?
- Patient has more energy
- May act on underlying suicidal impulses
Why would you give patients with chronic pain antidepressants?
- May treat depression which is underlying the chronic pain
- Also work when depression is not apparent
- May correct alterations in sleep patterns
- May affect serotonin and other monoamines which are important in regulation of pain pathways
What is the main drug for bipolar disorder?
Lithium
- makes the system more stable and prevents overexcitation
What is the main problems with lithium?
Not metabolized, only excreted
- builds up in body to toxic levels
What are the antiseizure medications?
- Carbamazepine
- Valproic acid
- Gabapentin (Neurontin)
- Lamotrigine
What are some antipsychotic medications?
- Clozapine
2. Risperidone
What are the pharmacokinetics of 2nd gen antidepressants?
A: Usually administered orally
D: Target of the drugs is the brain
M: Liver; Metabolites of some drugs have antidepressant activity
E: biotransformation and renal excretion
What are the types of drugs used to treat bipolar disorder other than lithium?
- Antiseizure medications
- Antipsychotic medications
- Both act to prevent neuronal excitability
- Both can be started with lithium, then tapered off
- Valproic acid or carbamazepine may be used with or instead of lithium to prevent relapses
What are some side effects of drugs that treat bipolar disorder that may interfere or limit PT intervention?
- Sedation
- Lethargy
- Muscle weakness
- Nausea and/or vomiting
What drug class is orthostatic hypotension most common?
TCA drugs
- can cause syncope
- risk of injury during falls
What drug class is a hypertensive crisis most common with? what should you do as a therapist to prevent this?
- MAO-I drugs
- Monitor blood pressure regularly, particularly during activities that increase blood pressure
A pt has a history of HTN and is taking beta-blockers. After an accident, pt becomes depressed and begins taking Trofanil. What should your concerns be with this patient?
Trofanil = TCA
- Postural hypotension, Particularly during early stages of drug administration
- Beta-blockers will limit the ability of the body to increase cardiac output - Start on tilt table, Parallel bars
- Limit standing early in therapy
- OBSERVE CAREFULLY
In the original amine hypothesis of depression, it was thought there is a decrease in neural transmission of _______
monoaminergic neurotransmitters
- affects limbic system
What is the modified amine hypotesis
- depression caused by increased sensitivity of beta-adrenergic receptor
- antidepressants increase monoaminergic transmission, but overall action is aimed at decreasing the sensitivity of postsynaptic beta-adrenorecptor (serotonin may have biggest role in this)
MOA: Block reuptake of monoamines into presynaptic terminals; Released monoamines remain in the cleft longer and stimulate the receptors more; Extended activation of receptors leads to decrease in receptor sensitivity
TCA
- for melancholy depression
- side effects limit overall use (cholinergic receptor binding)
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