Drugs that act on Central Nervous System PDF

Diploma in Healthcare Drugs that act on Central Nervous System Please do not reproduce, redistribute or share without the prior express permission of the author. UNIT 7 DRUGS THAT ACT ON CENTRAL NERVOUS SYSTEM Please do not reproduce, redistribute or share without the prior express permission of the...

Diploma in Healthcare Drugs that act on Central Nervous System Please do not reproduce, redistribute or share without the prior express permission of the author. UNIT 7 DRUGS THAT ACT ON CENTRAL NERVOUS SYSTEM Please do not reproduce, redistribute or share without the prior express permission of the author. Topic/ Chapter Learning Outcome 1. Understand the function of central nervous system. 2. Describe about nerve impulse transmission, synapses and neurotransmitters. 3. Describe Central Nervous System (CNS) stimulants. 4. Define convulsion and describe about anticonvulsants. 5. Describe Parkinson’s disease and antiparkinsonism drugs. 6. Identify types of anesthesia and related drugs. Please do not reproduce, redistribute or share without the prior express permission of the author. NERVOUS SYSTEM Central Nervous System Brain Spinal Cord Peripheral Nervous System Somatic Nervous System Autonomic Nervous System Sensory Neurons Sympathetic Nervous System Motor Neurons Parasympathetic Nervous System Please do not reproduce, redistribute or share without the prior express permission of the author. The Neuron Neuron- Basic functional cell of the nervous system Presynaptic Neuron - Neuron generating the original impulse Postsynaptic Neuron - Neuron waiting to receive the impulse Please do not reproduce, redistribute or share without the prior express permission of the author. Neurotransmitters (NT) Neurotransmitters are often referred to as the body’s chemical messengers. They are the molecules used by the nervous system to transmit messages between neurons, or from neurons to muscles. Can be Excitatory neurotransmitters or Inhibitory neurotransmitters. Each neuron generally synthesizes and releases a single type of neurotransmitter. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Types of drugs act on neurotransmitters 1. AGONIST - mimic the Neurotransmitters 2. ANTAGONIST - block the Neurotransmitters 3. REUPTAKE INHIBITOR - increase the concentration of Neurotransmitter Please do not reproduce, redistribute or share without the prior express permission of the author. CNS Stimulants MOA: Stimulate the respiratory center in carotid arteries, Produce wakefulness Suppress the appetite. Examples: Amphetamines, anorexiants Uses: To treat respiratory depression To relieve fatigue (coffee, tea) Short term treatment of exogenous obesity. Please do not reproduce, redistribute or share without the prior express permission of the author. Adverse reactions: Excessive CNS stimulation Headache, dizziness, insomnia Hyperactivity Excitements Nervousness Please do not reproduce, redistribute or share without the prior express permission of the author. Epilepsy Epilepsy – Disorder of CNS in which patients may have convulsion or seizures. Seizure – periodic attack of disturbed cerebral function (repeated coordinated but inappropriate movements) Epilepsy is defined as a permanent seizure disorder. Please do not reproduce, redistribute or share without the prior express permission of the author. Antiepileptic drugs MOA: Reduce the excitability of the neurons (nerve cells) in the brain. This result in reduced seizure. Uses: To relieve seizure Adverse reactions: Nausea & vomiting Constipation Hepatotoxicity. Please do not reproduce, redistribute or share without the prior express permission of the author. Parkinson’s Disease Parkinsonism – Neurological disorder of muscle movement. Caused by deficiency of dopamine and excess of acetylcholine within the CNS. Parkinson disease affects the part of brain that control muscle movements. Symptoms: tremor, muscular rigidity and difficulty in walking. No cure for Parkinson disease, but the symptoms can relieved using anti-parkinsonism drugs. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Anti-parkinsonism drugs Dopaminergic drugs MOA: Increase the production of dopamine Promote the activation of dopamine receptors Anticholinergic drugs MOA: Decrease the production of acetylcholine Prevent the activation of acetylcholine receptors Please do not reproduce, redistribute or share without the prior express permission of the author. Uses: To treat signs and symptoms of parkinsonism. Adverse reactions: Mental changes Nausea & vomiting Increased hand tremor Headache Please do not reproduce, redistribute or share without the prior express permission of the author. Anesthesia & Anesthetic drugs Anesthesia – Loss of feeling or sensation Anesthetic drugs – Drug used to induce anesthesia MOA: Temporarily inhibit nerve impulse transmission (especially pain impulse) to the brain, thus causes loss of sensation. Please do not reproduce, redistribute or share without the prior express permission of the author. Types of Anesthesia Anesthesia Local Anesthesia Topical Anesthesia Local Infiltration Anesthesia General Anesthesia Regional Anesthesia Please do not reproduce, redistribute or share without the prior express permission of the author. Local Anesthesia Local Anesthesia – Loss of sensation in a specific area. The patient is fully awake but does not feel pain in the area that has been anesthetized. In some cases patient may be sedated. Although not fully awake, the sedated patient may still hear what is going on around them. Please do not reproduce, redistribute or share without the prior express permission of the author. Topical Anesthesia Involves application of anesthetic drugs to surface of skin and mucous membrane. Local infiltration Anesthesia Injection of a local anesthetic drugs into tissues. Regional Anesthesia Injection of anesthetic drug around nerves so that area supplied by these nerves will not send pain impulse to the brain. Please do not reproduce, redistribute or share without the prior express permission of the author. General anesthesia General Anesthesia – Loss of sensation of entire body. Patient is unconscious and feel no pain. Volatile liquid anesthetics produce anesthesia when their vapours are inhaled. Gas anesthetics are combined with oxygen and administered by inhalation. Example of gas anesthetic is nitrous oxide. Please do not reproduce, redistribute or share without the prior express permission of the author. 7.2 Tranquilizers & Antidepressants Please do not reproduce, redistribute or share without the prior express permission of the author. OBJECTIVES At the end of the lesson, students should be able to: 1. 2. 3. 4. 5. 6. 7. Understand types of neurotransmitters & nerve impulse transmission. Define types of Hypnotic and Sedative agents. Identify the usage and adverse effects of Hypnotics and Sedatives. Define types of Anti-anxiety agents. Identify the usage and adverse effects of Anti-anxiety. Define types of Antidepressant agents. Identify the usage and adverse effects of Antidepressants. Please do not reproduce, redistribute or share without the prior express permission of the author. Topic/ Chapter Learning Outcome 1. Understand types of neurotransmitters & nerve impulse transmission. 2. Define types of Hypnotic and Sedative agents. 3. Identify the usage and adverse effects of Hypnotics and Sedatives. 4. Define types of Anti-anxiety agents. 5. Identify the usage and adverse effects of Anti-anxiety. 6. Define types of Antidepressant agents. 7. Identify the usage and adverse effects of Antidepressants. Please do not reproduce, redistribute or share without the prior express permission of the author. Neurotransmitters & their roles Dopamine - Involved in movement, attention, emotion. Deficiency will cause Parkinson’s Disease. Serotonin - Involved in mood, hunger, sleep. Deficiency will cause Depression. Norepinephrine - Involved in alertness. Deficiency will cause Depression. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. A chemical Synapse Please do not reproduce, redistribute or share without the prior express permission of the author. SEDATIVES AND HYPNOTIC (TRANQUILIZERS) Sedatives Sedative is a drug that produces a relaxing and calming effect. Can make patient drowsy but do not produce sleep. Hypnotics Hypnotic is a drug that induces sleep. Allow the patient to fall asleep and stay asleep. Please do not reproduce, redistribute or share without the prior express permission of the author. Barbiturate Sedatives & Hypnotics Ultrashort-acting 20 minutes Short-acting 3 to 4 hours Intermediate-acting 6 to 8 hours Long-acting 10 to 16 hours Benzodiazepines Please do not reproduce, redistribute or share without the prior express permission of the author. Barbiturates MOA: Facilitate the action of GABA (inhibitory neurotransmitter) GABA will inhibit or slow down the impulse transmission. Barbiturates increase the length of time of chloride channel remains open. High number of chloride ion will inhibit impulse transmission & cause CNS depression The patient will become calm & relax Please do not reproduce, redistribute or share without the prior express permission of the author. Mechanism of Action of Barbiturates Please do not reproduce, redistribute or share without the prior express permission of the author. Effects of Barbiturates CNS depression Mild sedation Hypnosis (sleep) Deep coma Respiratory depression * Effects will diminished after approximately 2 weeks Please do not reproduce, redistribute or share without the prior express permission of the author. Therapeutic Uses To treat insomnia (sleeping disorder) Given the night before the operation to prepare the patient for surgery. Please do not reproduce, redistribute or share without the prior express permission of the author. Adverse Reactions CNS - CNS depression, sedation & hallucination Respiratory - Respiratory depression Gastrointestinal - Nausea & vomiting, Cardiovascular – Bradycardia & hypotension Hypersensitivity - Rash, fever Please do not reproduce, redistribute or share without the prior express permission of the author. Anti-anxiety Drugs (Tranquilizers) Anxiety Anxiety - Feeling of apprehension, worry or uneasiness that may not based on reality. Excess anxiety interferes with day-to-day functioning and can cause undue stress. Drug used to treat anxiety are anti-anxiety drugs. Please do not reproduce, redistribute or share without the prior express permission of the author. benzodiazepines Anti-anxiety Drugs Non-benzodiazepines Please do not reproduce, redistribute or share without the prior express permission of the author. Benzodiazepine MOA: Increase or help the effects GABA. MOA is similar to Barbiturates Chloride channel opened for long period of time Inhibit impulse transmission & cause CNS depression. Patient become calm & relax Please do not reproduce, redistribute or share without the prior express permission of the author. Mechanism of Action of Benzodiazepine Please do not reproduce, redistribute or share without the prior express permission of the author. If barbiturates and benzodiazepine are given together, The chloride channel will remains open for a very long time. Too many chloride ions will enter the cell Nerve impulse transmission totally will be stopped. The patient will be unconscious. Please do not reproduce, redistribute or share without the prior express permission of the author. MOA of Barbiturates & Benzodiazepine Please do not reproduce, redistribute or share without the prior express permission of the author. Non-benzodiazepine MOA: Act on the brain’s dopamine and serotonin receptors. Non-benzodiazepines will, Blocks the receptors on the brain. Inhibit impulses from entering the brain. This will cause CNS depression The patient will become calm & relax. Please do not reproduce, redistribute or share without the prior express permission of the author. Therapeutic Uses Used to treat anxiety disorders Also used as Sedatives Muscle relaxant Adverse Reactions Fatigue Anger Constipation Dry mouth Nausea Visual disturbance Please do not reproduce, redistribute or share without the prior express permission of the author. Anti-depressant Drugs Depression Most common psychiatric disorders. Feeling of intense sadness, helplessness, worthlessness and impaired functioning. Depression is treated with anti-depressants. There are 4 types of Anti-depressants. Please do not reproduce, redistribute or share without the prior express permission of the author. Tricyclic antidepressants (TCAs) Anti-depressant Drugs Monoamine oxidase inhibitors (MAOIs) Selective serotonin reuptake inhibitors (SSRIs) Miscellaneous unrelated drugs Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. MOA of Antidepressants Some Antidepressants block the reuptake of the endogenous neurotransmitters. Thus a lot of neurotransmitters are involved in impulse transmission. This will cause CNS stimulation. The patient will become excited & relieve from depression. Please do not reproduce, redistribute or share without the prior express permission of the author. Please do not reproduce, redistribute or share without the prior express permission of the author. Examples of antidepressants: Tricyclic Antidepressants (TCAs) Inhibit uptake of norepinephrine and serotonin into the same neuron. Selective Serotonin Reuptake Inhibitors (SSRIs) Inhibit the uptake of serotonin into the same neuron. Please do not reproduce, redistribute or share without the prior express permission of the author. Some Antidepressants will inhibit the enzymes that can destroy neurotransmitters. Since the enzymes are destroyed, lots of neurotransmitters are involved in impulse transmission. This will cause CNS stimulation. The patient will become excited & relieve from depression. Please do not reproduce, redistribute or share without the prior express permission of the author. Examples of Antidepressants: Monoamine Oxidase Inhibitors (MAOIs) Inhibit the activity of Monoamine Oxidase enzyme (enzyme that destroy Monoamine neurotransmitters) Please do not reproduce, redistribute or share without the prior express permission of the author. Therapeutic Uses Used to manage Depression To reduce pain Prevent migrane Treat premenstrual syndrome Please do not reproduce, redistribute or share without the prior express permission of the author. Adverse Reactions Orthostatic hypotension Mental confusion Nausea & vomiting Visual disturbance Constipation Hypertension Insomnia Please do not reproduce, redistribute or share without the prior express permission of the author. Reference Holland, LM and Adams MP. 2007. Core Concepts in Pharmacology. 2nd edition.Pearson. Hitner H and Nagle B. 2002. Basic Pharmacology. 4th edition. McGraw-Hill. Please do not reproduce, redistribute or share without the prior express permission of the author. Next Topic Drugs that affect the Autonomic Nervous System Please do not reproduce, redistribute or share without the prior express permission of the author. Thank you Address Lot 33-40, Blok C, Plaza Juta, KM 7.2 Off Jalan Tuaran, 88400 Likas, Kota Kinabalu, Sabah, Malaysia Telephone +6088 431 025/35 Website kk.cyberjaya.edu.my Email [email protected] Please do not reproduce, redistribute or share without the prior express permission of the author.