Term
| Describe the CNS effects of benzodiazepines (BZs), barbiturates, and alcohols? |
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Definition
-BZs plateau off before coma (not GABA mimetic)
-Barbs & alcohol both are able to progress to coma and death (GABA mimetic at high doses) |
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Term
| What does the GABA receptor look like and where do the drugs bind? What are the GABA receptor types and how do they work? |
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Definition
-α(x2) β γ δ ρ subunits
-GABA(x2)-->α(x2)
-BZs--γ (BZ receptor location)
-Barbiturates-->β
-*GABA-A; Cl- influx (all except baclofen bind here)
-GABA-B; K+ efflux
-Both give hyperpolarization (inhibition) |
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Term
| What is characteristic of BZ receptor antagonism? What is the action? What reverses them? |
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Definition
-BZ1 receptor; sedation
-BZ2 receptor; antianxiety and impairment of cognitive function (can cause *anterograde amnesia)
-They raise the frequency of Cl- channels opening (potentiate GABA); see curve on 141
-There is no mimetic activity at any levels (plateau)
-Reverse with **flumazenil BZ; receptor antagonist |
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Term
| What about for barbs action? |
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Definition
-They prolong GABA activity (inc. Cl- opening duration)
-GABA mimetic at high doses
-Can inhibit ETC at **complex one
-Inducers of P450s (because they are metabolized) resulting in more heme production-->contraindication in porphyria (see 142 for full info) |
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Term
| What are the major BZs (6)? |
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Definition
1. Alprazolam
2. Diazepam
3. Lorazepam
4. Midazolam (also in anestesia chapter)
5. Temazepam
6. Oxazepam
-End in -azepam or -azolam
-First 3 are anxiolytic, last 2 are for sleep disorders
-See *141 for full info |
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Term
| What are the major barbiturates (2)? |
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Definition
1. Phenobarbital-->seizures
2. Thiopental-->induction of anesthesia (Ch4)
-Look for "-barbital" or "-pental"
-With these we have to worry more about addiction, cross tolerance (higher doses for alcoholics), and dangerous additive effects (Heath Ledger) |
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Term
| What do we have to worry about with additive effects? |
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Definition
| -Alcohol, antihistamines (M blockers), opiates, B-blockers (lower SANS), can all mix with barbs and BZs to give deadly effects |
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Term
| What do we see in withdrawal from GABA-A drugs? What do we use to treat withdrawal? |
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Definition
-Basically exaggerations of what they treat; anxiety, agitation, and seizures (delirium tremens with alcohol)
-Use lorazepam or diazepam to treat (longer acting ones) |
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Term
| What are the 3 non-BZ drugs that act on BZ receptors? |
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Definition
-Zolpidem, zaleplon, eszopiclone (Lunesta); the ZZZ drugs
-Both act on **BZ1 receptors; selective for sedation**
-All used for sleep disorders
-Can also be reversed with flumazenil if need be |
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Term
| What is the last one we can give for anxiety? What does it act on? |
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Definition
-Buspirone
-5-HT(1A) partial agonist; gives it a duality for balancing the anxiety/depression nature inherent to these receptors
-Takes 1-2 weeks to take effect (like antidepressants) |
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