psychopharmacology 2
Terms
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- tricyclic
- Imipramine (tofranil)
- Benzodiazepine
- Valium, Zanax, Clonopine, Transine, Lipiam
- SSRI
- Prozac (fluoxetine), Zelexa, Lexapro, Zoloft, Luvox, Paxil
- Atypical or Novel antidepresents
- Zyprexa
- Psychopharmalogical Treatment of Alcohol Abuse
-
Campral
(Acamprosate [gentic name]) - Treatment for Opiod Dependence
-
Revia (Naltrexone)
Buprenorphine (Subutex) - Pharmacokinetics
- The movement of the drug throught the body. (What the body does to the drug)
- Three basic concepts of Pharmacokinetics
-
Absorption
Distribution
Metabolism - Absorption
- swallow the drug, sublinguli, injected (intermuscular), injecting the drught right into the blood stream (intervenues), trandezmal (patch)
- Distributed
- depending on the molecular of the drug (How much like water or like fate they are.)
- Metabolism
- How the drug is going to be broken down by the body
- Peak Plasma Level (PPL)
- How long after the drug absorbs through the body. Does it take for it to absorb through the blood.
- T1/2
- Half life the amt of time that it takes the body to eliminate the drug by 50%
- T1/2 of Lithum
- is 24 hours
- T1/2 of Prozac
- is 7 to 9 days
- steady state
- the body maintaining the same level of blood all the time. It is achieved if the person takes the drug at at a frequency some what greater then the half life for 5 half lives. Example, Zelexa has a half life of one day, then it takes 5 days for it to become a steady state.
- Pharmokenetics
- measure used to indicate the pattern of distribution of a drug in plasma and in the different tissues, as well as the size of the compartment into which a drug would seem to have distributed in relation to its concentration in plasma, is known as the apparent volume of distribution (Vd).
- Clearance
-
Drug clearance (Cl) is defined as the volume of plasma that would contain the amount of drug excreted per minute or, alternatively, the volume of plasma that would have to lose all of the drug that it contains within a unit of time (usually 1 min) to account for an observed rate of drug elimination. Thus, clearance expresses the rate or efficiency of drug removal from the plasma but not the amount of drug eliminated. The concept of drug clearance is of great clinical significance.
Impaired kidney functionwill decrease the clearance process. - first-pass effect (or first-pass metabolism)
-
is a phenomenon of drug metabolism.
After a drug is swallowed, it is absorbed by the digestive system and enters the portal circulation. The absorbed drug is carried through the portal vein into the liver.
The liver is responsible for metabolizing many drugs. Some drugs are so extensively metabolized by the liver that only a small amount of unchanged drug may enter the systemic circulation, so the bioavailability of the drug is reduced. - Pharmacodynamics
- is the study of the biochemical and physiological effects of drugs and the mechanisms of drug action and the relationship between drug concentration and effect. It is often summarily stated that pharmacodynamics is the study of what a drug does to the body, whereas pharmacokinetics is the study of what the body does to a drug.
- GABA receptors
- GABA is the chief inhibitory neurotransmitter in the mammalian brain. Along with glycine--that primarily has effects in the spine, brainstem and retina--it is responsible for the vast majority of all inhibitory neurotransmission in the central nervous system (CNS). Between 20-50% of all central synapses use GABA as their transmitter. The enzyme responsible for the formation of GABA from the amino acid glutamate is glutamic acid decarboxylase (Dawson et al., 2005).
- Predominent inhibitor of the brain
- GABA
- The more negatively charged the interior of the cell
- the more difficult it is for an action potential to happen. There by making the interior of the cell more negative and less excitable. That is how valium and xanax work.
- A healthy can not overdose on
- Benzodiazepene because no more GABA to go into GABA receptors.
- Be able to draw the Benzodiazepene GABA complex
- Benzodiazepines, barbiturates, convulsants, steroids, and alcohol modulating agents alter GABA’s efficiency by inducing a change in the protein architecture of the GABA-A complex. This change modifies the size of the channel, which in turn modifies the receiving neuron’s permeability to chloride ions. Since chloride ions are negatively charged, when they enter the neuron, they hyperpolarize it.
- Therapeutic Index
-
The ratio between the toxic dose and the therapeutic dose of a drug, used as a measure of the relative safety of the drug for a particular treatment.
LD50/TD50 (lethal dose 50% of the pop/therapeutic dose 50% of pop.) - Lithium TI
- 2400LD/1200TD = 2
- Prozac TI
- >2000mg/20 = >100
- Different drugs TI
- Some drugs have a high TI and some have lower TI = therefore higher TI are safer.
- Betablockers
- have never been approved for anxiety, they have been proved by the FDA for cardiology.
- dose-response curve
- A dose-response curve is a simple X-Y graph with X usually being the measured dose (usually in milligrams, micrograms, or grams per kilogram of body-wieght) and Y being the response.
- therapeutic window
- The range of plasma drug concentrations with a high probability of therapeutic success.
- Dependence
- requiring a cetain level of the drug in order not to experience withdrawal ie 20 mgs of clonopine - if the person would sudenly stop then they would start experiencing the withdrawal symptoms.
- Tolerance
- once a person has began the take of certain amount of drugs can not feel the effect of a smaller amount of the drug.
- Antipsychotic Medications
- Antipsychotic medications have been available since the mid-1950s. They have greatly improved the outlook for individual patients. These medications reduce the psychotic symptoms of schizophrenia and usually allow the patient to function more effectively and appropriately.
- Two broad categories AP (Antipsychotic)
- Typical (Classical) and Atypical (Novel)
- Atypical Antipsychotic Medications
- A number of new antipsychotic drugs (the so-called "atypical antipsychotics") have been introduced since 1990. The first of these, clozapine (Clozaril), has been shown to be more effective than other antipsychotics, although the possibility of severe side effects - in particular, a condition called agranulocytosis (loss of the white blood cells that fight infection) - requires that patients be monitored with blood tests every one or two weeks. Studies show that clozapine works in 30% of patients who have failed all traditional antipsychotic medications. Even newer antipsychotic drugs, such as risperidone (Risperdal), quetiapine (Seroquel), olanzapine (Zyprexa), and Abilify (Aripiprazole) are safer than the older drugs or clozapine, and they also may be better tolerated.
- risperidone (Risperdal)
- appears to have somewhat lower antipsychotic effectiveness, but a greatly improved side-effect profile compared to older medications. Some studies suggest that it also had some antidepressant effects, probably due to its effects on serotonin metabolism.
- Abilify (Aripiprazole)
- is even newer and may have other advantages.
- Atypical medications have several advantages
- over traditional medications: fewer anticholinergic side-effects, less Parkinsonism and dystonia, very low risk of tardive dyskinesia and reversal of many 'negative symptoms' of schizophrenia such as affective blunting, withdrawal, and low motivation. These newer medications all appear to primarily influence dopamine receptors but they also appear to affect serotonin receptors that deal with frontal lobe functions.
- Olanzapine (Zyprexa)
- is described as a safer version of clozapine. It appears to be similar in efficacy and reversal of negative symptoms but free of the risk of agranulocytosis.
- Typical (classical)
- effective only on the positve symptoms: Thorazine (chlorpromazine), Haldo (Haloperidol), Prolixin (fluphenazine), Navane ( thiothixene).
- Mechanism of actio of AP
- Typical AP - Pharmacodynamic criteria is that they block copamine D2 receptors.
- 3 pathways of Dopamine
- A dopamine projection from the hypothalamus plays an important role in the regulation of prolactin release from the pituitary gland. Dopamine also is synthesized by neurons in the ventral tegmental area, which projects to the prefrontal cortex and the basal forebrain, including the nucleus accumbens. Another important dopamine pathway is from the substantia nigra pars compacta to the neostriatum.
- Two sub categories of typical classical
-
Hipotency Typical AP- Haldo 2mgs; Prolixin.
Low Potency Typical AP - Thorazine 50 mg; Mellari = Equaly as effective Haldol 2mgs = Thorazine 50 mgs. - Movement disorder side effects are more frequent
- Hi Potency AP; also experience endro side effects.
- Non nuerological side effects
- are more frequent with Low Potency - endro side effects.
- Alpha blocking effect = alphalytic affected
- by the low potency medication. Side effects include orthro static hypotension - standing up straight. Low potency AP block a receptor that is present in the periferal nervous system called alpha.
- Norepinephrine (adrenaline)
- Anticholorogic side effect- unusual in High potency AP
- Dopamine Pathways
-
Nigrostriatal system projects from the substantia nigra to the caudate nucleus and putamen
Mesolimbic system projects from ventral tegmental area to the limbic system (including the nucleus accumbens, amygdala, and hippocampus)
Mesocortical system projects from the ventral tegmental area to the cortex