1. Pharmacology Nursing C ONTINUE CNS D RUGS Lecture 7

2. A NESTHETICS  Major categories of anesthesia: 1. General: used to supress CNS functions so deeply as to reduce consciousness and block sensation of pain during surgery, could be IV or inhalational,  Inhalational anesthetics:- provide rapid suppression on the CNS. i. Cyclopropane gas ii. Nitrous oxide gas iii. Halothan.  Intravenous anesthetics have short duration of action. i. Thiopental ii. Ketamine iii. Midazolam

3. 2. Regional: administration of a local anesthetic to block spesific region of the body; spinal and epidural anesthesia. 3. Local: administration to produce a loss of sensation surronding an operative field; applied topically or as S.C injection. i. Lidocaine ii. Procaine  Both types have no effect on the level of concoiusness.

4. Preanesthetic drugs 1. Skeletal muscle relaxants, to facilitate intubation and relaxation. 2. Diazepam,barbiturates, as sedative, anxiolytic. 3. Atropine; anticholinergics, decrease secretions and prevent bradycardia 4. Antiemetics, to prevent emesis,and aspiration of stomach cotents 5. Antihistamines, to prevent allergic reactions. 6. Opiods, provide analgesia.

5. CNS STIMULANTS  Two general mechanisms: Increase excitatory neurotransmitter release Decrease inhibitory neurotransmitter release  Common CNS stimulant drugs 1. Amphetamines Promote the release of norepinephrine, dopamine  Effects:  alertness  Fatigue  appetite Insomnia  Uses 1.ADHD 2.Narcolepsy  Examples Dextroamphetamine

6.  Used to treat Attension Deficit Hyperacivity Disease (ADHD), it increases ability to focus & concentrate.  Side Effects Tachycardia, Hypertension, Convulsion, Insomnia, Psychosis, potential for addiction 2.Methylphenidate

7. 3. Methylxanthines  Caffeine Theophylline Theobromine  Mechanism of action 1. Reversible blockade of adenosine receptors 2. CNS stimulation, increased alertness. 3. Decreased fatigue. 4. Stimulating effect on heart (increase contractility) 5. Have mild diuretic effect 6. Increase the gastric secreations.  Side effects: Insomnia, anxiety and agitation……mild dose Emesis, convulsions, and cardiac arrhythmias………Toxicity (100 cups of coffee) *Physical dependence on caffeine

8. 4. Nicotine  The active ingredient in tobacco.  Used only in smoking cessation treatment.  At low doses  1) sympathetic ganglia stimulation. 2) euphoria, arousal, and relaxation 3) hypertension and tachycardia.  At high doses  1) parasympathetic block 2) respiratory paralysis and hypotension.  Appetite suppressant  Addictive substance……withdrawal symptoms

9. A NTIPSYCHOTIC A GENTS  Mechanism : Antipsychotic (neuroleptic,tranquilizers) drugs block CNS dopamine and/or serotonin receptors.  Uses of antipsychotics Schizophrenia (primary use) Tourette’s syndrome Senile dementia associated with Alzheimer disease. Prevention of severe nausea

10. D RUGS  Typical Affect dopamine receptors 1. Chlorpromazine 2. Haloperidol 3. Procholrperazine  Atypical Affect dopamine and serotonin receptors 1. Clozapine 2. Risperidone. They are not curative, but they decrease the intensity of the symptoms.

11.  Actions:  Antipsychotic actions:  Reduce hallucinations by blocking dopamine receptors.  Extrapyramidal effects:  Parkinson syndrome by blocking the dopamine receptors in the nigrostriatal pathway.  Antiemetic effects:  By blocking dopaminergic receptors.  Antimuscarinic effects:  Blurred vision, dry mouth, sedation and confusion. Effects are antagonized by: levodopa, amphetamine, bromocriptine. Contraindicated in cases of parkinsonism.

12. D RUGS FOR NEURODEGENERATIVE DISEASES  Parkinsons disease brain disease due to imbalance in dopamine/ acetylcholine  impaired motility  Muscle rigidity  Tremors  Bradykinesia  Huntington disease  Progressive dementia  Involuntary muscle twitching

13. DRUGS  Dopaminergic drugs 1. Levodopa +carbidopa (Sinemet )It is a precursor of dopamine 2. Amantadine (Symmetrel ) antiviral, supposed to increase the release of dopamine. 3. Bromocriptine (Parlodel), Direct acting dopamine agonist. 4. Selegiline; It is MAO-B enzyme inhibitor, so it inhibits the dopamine metabolism leading to its accumulation  Anticholinergic drugs: Benztropine, procyclidine decrease salivation, tremors and rigidity.

14. Levodopa +Carbidopa