1 / 20

CNS Drugs

CNS Drugs. Dr. Felix Hernandez M.D. Neurotransmitters of the Brain. Dopamine Synthesized from Dopa Over stimulation leads to psychoses Too little dopamine is seen in Parkinson’s Disease Impaired transmission is implicated in depression, ADD, and narcolepsy Serotonin

nituna
Download Presentation

CNS Drugs

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. CNS Drugs Dr. Felix Hernandez M.D.

  2. Neurotransmitters of the Brain • Dopamine • Synthesized from Dopa • Over stimulation leads to psychoses • Too little dopamine is seen in Parkinson’s Disease • Impaired transmission is implicated in depression, ADD, and narcolepsy • Serotonin • Synthesized from the AA tryptophan • Is released from inhibitory neurons • LSD stimulates the same receptors as serotonin • Imbalances are associated with depression, ADD and headaches • GABA • An inhibitory NT • Cause hyperpolarization of neurons making it harder for them to fire • Low levels have been implicated in anxiety and seizures

  3. Tricyclic Antidepressants • MOA: • Block the reuptake of monoamine NT (Dopamine) thus increasing their levels in the synapse. • Possible that a subsequent downregulation of the receptors is the actual MOA • Interactions: Potentiate the effects of other CNS depressants and anticholinergic drugs • Amitriptyline • Indications: major depressive disorder, enuresis, agoraphobia, OCD, migraines • Side Effects: severe anticholinergic effects, sedation • Imipramine • Indications: Enuresis in children. Was the TCA DOC but is no longer used due to its side effects • Side Effects: similar to others but can induce arrhythmias

  4. Selective Serotonin Reuptake Inhibitors • Mechanism of action: Selectively inhibit the reuptake of serotonin • Fluoxetine (Prozac) • Inidications: depression, OCD, bulimia nervosa • Side Effects: altered platelet function, increased suicide rate • Interactions: life-threatening reaction with cisapride (promotes the release of ACH in the GI) • Sertraline (Zoloft) • Indications: depression, OCD, panic disorder • Side Effects: dry mouth, insomnia, altered platelet function • Interactions: Similar to fluoxetine

  5. Selective Serotonin Reuptake Inhibitors • Paroxetine (Paxil) • Indications: depression, OCD, panic disorder • Side Effects: somnolence, insomnia, weakness, abnormal ejaculation, altered platelet function • Interactions: cimetidine (Histamine blocker used for ulcers) increases its levels. Warfarin levels are increased. Digoxin levels are decreased. • Trazodone • Indications: depression, aggressive disorders, cocaine withdrawl • Side Effects: Rash, HTN, Tachycardia, SOB, priapism

  6. Benzodiazepines • Alprazolam (Xanax) • MOA: Increase levels of GABA thus making it harder for neurons to fire • Indications: Used together with TCA to treat depression and panic attacks • Side Effects: Has no anitcholinergic effects. Causes sedation and lethargy • Interactions: additive with other CNS depressants

  7. Buproprion (Wellbutrin) • MOA: Unknown • Indications: depression and smoking cessation • Side Effects: seizures, hepatotoxicity, anticholinergic effects • Interactions: don’t use with drugs that lower seizure threshold

  8. Stimulants • D-Amphetamine (Adderall and Dexedrine) • MOA: releases biogenic amines (NE, dopamine and serotonin) from storage vesicles • Indications: narcolepsy, ADD • Side Effects: restlessness, insomnia, HTN, arrhythmia, anorexia, psychotic episodes • Interactions: TCA potentiates the CNS effects by inhibiting the metabolism of amphetamine • Special Notes: to treat OD you acidify the urine, give chlorpromazine (Thorazine-sedation) to reduce CNS effects and an alpha blocker for the HTN • Methylphenidate • Same thing but milder stimulation

  9. Stimulants • Caffeine • MOA: Adenosine receptor blocker. Stimulates CNS, constricts cerebral artreioles, induces diuresis • Indications: prolonged apnea in pre-term infants, headache analgesics • Side Effects: insomnia, restlessness, tachycardia, diuresis • Interactions: oral contraceptives and cimetidine inhibit its metabolism, smoking enhances elimination

  10. Antiemetic • Promethazine (Phenegran) • MOA: dopamine and histamine antagonist • Indications: motion sickness, N&V (Post anesthesia) • Ondansetron (Zofran) • MOA: serotonin receptor blocker (not dopamine) • Indications: control chemo induced N&V

  11. Parkinson’s Disease Drugs • Levodopa (L-Dopa) • MOA: is decarboxylated to dopamine (DA) • Improves neuro, motor and psych s/sx of parkinson’s • Indications: parkinson’s disease • Side Effects: N&V, modest ortho hypo, arrhythmias in elderly, involuntary movements, increased sexual activity • Interactions: pyridoxine (B6) reduces its effects, antipsychotics block dopamine receptors, anticholinergics delay absorption • Special notes: always used with carbidopa which inhibits its decarboxylation

  12. Parkinson’s Disease Drugs • Carbidopa • MOA: deminishes the decarboxylation of L-Dopa in peripheral tissues therefore increasing the effect of L-Dopa • Indications: Parkinson’s Dz • Side Effects: reduces the N&V associated with L-dopa • Interactions: None • Has no MOA when given alone • Amantadine • MOA: releases dopamine from intact terminals • Side Effects: at high doses hallucinations, confucion and nightmares • Interactions: anticholinergic drugs enhances the CNS side effects • Is less effective than L-Dopa but more effective than anticholinergics

  13. Parkinson’s Disease Drugs • Bromocriptine • MOA: powerful dopamine receptor agonist • Indications: Parkinson’s with tolerance to L-Dopa, hyperprolactinemia, pituitary tumors • Side Effects: N, hallucinations, hypotension • Interactions: can be used with L-Dopa and carbidopa

  14. Opioid Analgesics • Morphine • MOA: opiate receptor agonist. Induces analgesia, sedation, respiratory depression • Indications: severe pain not alleviated by non-narcotics. DOC for severe pain in MI • Side Effects: respiratory depression, constipation, orthostatic hypotension, cholestasis, constipation • Tolerance can develop to the analgesic effects but not the constipating effects • Analgesia is threefold: • Increased threshold, unpleasant psych response is reduced, sleep is induced

  15. Opioid Analgesics • Oxycodone (Oxycontin) • MOA: Same as morphine • Indications: moderate to severe pain • Side Effects: same as morphine • Used because it has a better oral absorption than morphine • Methadone • MOA: full morphine actions with less sedative effects • Indications: detox of narcotic addiction (Heroin), severe pain in hospitalized patients • Is less psychologically addictive than morphine • You detox by replacing heroin addiction with methadone addiction and then you slowly lower the dose of methadone to zero

  16. Opioid Analgesics • Fentanyl • MOA: same MOA as morphine but is more potent with a lower likelihood of respiratory depression • Indications: preoperative uses • Side Effects: muscle rigidity, mild bradycardia • Has no tolerance or dependence • Can be used to treat chronic pain by using the transdermal preparations • Codeine • MOA: is a prodrug  10% of the drug is converted to morphine. So the MOA is the same as morphine • Indications: minor pain relief and antitussive • Side Effects: similar to morphine but less intense, but if given in high doses it’s toxicity is as severe as morphine • Included in several cough meds

  17. Opioid Antagonists • Naloxone • MOA: blocks opiod receptors but only has an effect on a person that has narcotics in their system • Indications: treatment of narcotic OD, diagnostic agent to evaluate narcotic addiction, reduces postoperative respiratory depression • Side Effects: induces narcotic withdrawal syndrome including LOA, muscle contractions, fever/chills, restlessness

  18. Benzodiazepines • MOA: bind to GABA receptors and enhances GABA mediated neuronal inhibition. Causes sedation, skeletal muscle relaxation and barbiturate fast waves on EEG • Indications: anxiety, DT’s, seizures, relaxation of Skeletal muscles • Side Effects: drowsiness, clouding of consciousness, ataxia, behavioral disinhibition, dermatitis • Interactions: effects are additive with ETOH

  19. Benzodiazepines • Diazepam (Valium) • Is long acting • Indicated for anxiety disorder • Midazolam (Versed) • Is short acting • Used in anesthesia • Alprazolam (Xanax) • Short acting • Used as an antidepressant and an anxiolytic • Used to treat panic attacks • Does not cause daytime drowsiness

  20. Migraine Headache Therapy • Sumatriptan (Imitrex) • MOA: serotonin receptor agonists • Causes vasoconstriction of the basilar artery and dura matter vessels • Onset of relief is 10 minutes – two hours • Side Effects: dizziness, tingling, flushing, chest discomfort, weakness and neck pain • Used to treat a migraine that is already occuring • Propranolol and timilol are used to prevent the onset of a migraine

More Related