Drugs affecting the Central-Nervous-System (CNS) & PAIN medications

Chapters 12 and 13MR160

Central Nervous System (the CNS)

• Stimulants – increase brain & spinal cord activity

• Depressants – decrease CNS activity, either specifically or generally (ANESTHESIA)

• Anti-convulsants (epilepsy) – goal is to depress the Motor Cortex

• Anti-parkinsonian – physical therapy used in early stages, then medication

CNS Stimulants

ADD & ADHD therapy• Adderall (amphetamine salts) - oral• Concerta (E/R methylphenidate) – oral• Daytrana (methylphenidate) – skin patch!• Ritalin (methylphenidate) – oral• Strattera (atomoxetine) – not controlled!Narcolepsy – Provigil promotes wakefulness

CNS Depressants (page 1)the STAGES of General ANESTHESIA are

characterized by the level, or ‘depth’

• Stage I – Analgesia: euphoria, amnesia

• Stage II – Delirium: increase involuntary muscle activity, irregular breathing, HTN, tachycardia

• Stage III – Surgical Anesthesia: until spontaneous respiration ceases, watch eyes & reflexes

• Stage IV – Medullary Depression: pupils fixed & dilated … no lid or corneal reflexes

CNS Depressants (page 2)

• HYPNOTICS and SEDATIVES• Daytime sedation – small doses• Sleep induction – larger doses• CAUTION: mixing w/ alcohol, antihistamines• morning ‘Hangover’ effect - greatly reduced

by use of short-acting agent or lower doses• Barbiturates – phenobarbital, secobarbital• Non-barbiturates – Ambien, flurazepam

--- Restless Leg Syndrome ---

• DOPAMINE RECEPTOR AGONISTS to treat Restless Leg Syndrome (RLS)

• technically –NOT- CNS-depressants !• Mirapex (pramipexole) – also sometimes

effective in Parkinsonism• Requip (ropinirole) – Parkinsonism also, but

may cause patient to fall asleep during daily activities!

Narcotic Analgesics

• OPIATES – derived from Opium (morphine, codeine)

• OPIOIDS – synthetic drugs with actions similar to opium/opiates

• The term ‘Narcotic’ includes both opiates & opioids (all are Controlled-substances)

• Most effective, but most ADDICTIVE analgesics• CAUTION: tolerance, physical dependence

------ OPIATES ------

• MORPHINE SULFATE MS Contin – controlled release MSIR – immediate release Roxanol – oral solution & concentrate• CODEINE * opiate or opioid OVERDOSE treatment = Narcan (naloxone) … ‘antidote’

----- OPIOIDS -----

• hydrocodone (Vicodin, Lortab, Norco) • oxycodone (OxyContin, OxyIR) • meperidine (Demerol) • methadone – some history --- alternate dosage-forms ---• fentanyl (Duragesic) – skin patches • butorphanol (Stadol) – nasal spray

non-Narcotic analgesics

• acetaminophen (APAP) – Tylenol• aspirin (ASA) --- chewable (Bayer, St. Joseph’s) --- buffered (Bufferin) --- enteric-coated (Ecotrin)• tramadol (Ultram) – abuse potential !• propoxyphene (Darvon) – no longer on the

market --abuse potential !

Drugs for MIGRAINE

• The TRIPTAN’s – not related to other analgesics

• ‘selective Serotonin Agonists’ • Primarily effective on headaches that are

vascular in nature …(not tension, cluster) • MOA = constricts vessels, blocks nerves• Imitrex (sumatriptan)-oral, injectable, nasal• Axert (almotriptan)

EPILEPSY• SEIZURE TYPES• Tonic-Clonic (Grand Mal) – last 2 – 5 minutes,

often followed by deep sleep • Absence (Petit Mal) – 1 to 30 seconds• Complex Partial – brief period of confusion• Epileptic ‘equivalents’ – these episodes

‘resemble’ seizures … causes? ---tetanus ---hypoglycemia ---drug-withdrawal

Drugs for Epilepsy (Seizures)pg 113-115

• ANTICONVULSANTS--Dilantin(phenytoin) --Tegretol(carbamazepine)• BENZODIAZEPINES--Klonopin(clonazepam) – Ativan (lorazepam) -- Valium(diazepam) …others …• Neurontin(gabapentin) – also for ‘neuralgia’ • Lamictal(lamotrigine) – stabilizes neuronal

membranes

PARKINSON agents

• PARKINSON’S DISEASE has no known cause, but seems to be related to depletion of dopamine in the brain

• “Secondary parkinsonism” may be caused by drugs (antipsychotic meds), toxins, or degenerative diseases (Alzheimer’s Disease)

• DOPAMINERGIC drugs--- levodopa/carbidopa (Sinemet)*see Table 12-4 for non-dopaminergic agents

Analgesics/Antipyretics

Chapter 13

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Analgesics & Pain• What does “pain” look like? • Pain evaluation is based on:– Location of pain– Duration– Intensity (1-10 scale)– Precipitating factors

• Pain may be Acute or Chronic:– Acute-short duration, responds to analgesics– Chronic-over time, less responsive to analgesics, tolerance

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Types of Analgesics

3 Classes

OpioidNon-opioid

Adjuvant17

Opioids & Opiates (Narcotics)

• OPIOID – a derivative of opium• OPIATE – a synthetic chemical that produces an

analgesic effect similar to opium.• Examples: codeine, morphine (opioids) &

oxycodone, fentanyl, meperidine (opiates)• Reduces pain from any origin• CAUTION: Tolerance and physical dependence• Many are Schedule II controlled substances

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Narcotic Analgesics Side Effects

• Euphoria, Sedation, Confusion• Slowed reaction time• Respiratory depression (in major overdose

situations)• Nausea, stomach upset• Constipation• “Idiosyncratic” (restlessness & agitation)

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Drug Interactions with Narcotics

• Alcohol & other CNS depressants can lead to Respiratory depression

*Sedatives *Antihistamines * benzodiazepines

• What drug is used to treat narcotic overdose? --- naloxone (Narcan)

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Non-opioid Analgesics

• For mild to moderate pain1. Not related to morphine2. Work on peripheral nervous system,

not the CNS (outside brain, spinal cord)3. Do not produce physical dependency

and tolerance4. Do not alter consciousness or mental

function

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Non-opioid Analgesics• low-intensity pain of inflammation and dull

aches and vague pain• Fever reduction • Used as

-analgesic -antipyretic, and/or

- anti-inflammatory • Not every drug in this class has all 3 effects

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more info on Non-opioid Analgesics

• Typically the first step in pain control• OTC or Rx• Less expensive that Narcotics• combined with narcotics to become Rx items: * Hydrocodone+APAP *Hydrocodone+ibuprofen *Oxycodone+APAP

• May be combined with non-narcotics to become Rx or OTC items:– ASA+caffeine -APAP+caffeine+butalbital (Fiorocet)

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Salicylate Analgesics (aspirin”ASA”)

• Oldest non-opioid analgesics; not for children• Four distinct therapeutic actions of ASA:

– 1. Analgesic – inhibits prostaglandin release from damaged tissues

– 2. Anti-inflammatory—reducing prostaglandin synthesis– 3. Anti-pyretic—reduces fever by causing vasodilation – 4. Anti-coagulant—prevents platelets from aggregating (clump)

to decrease clot formation

• Beware GI effects, bleeding out

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Acetaminophen (APAP)

• Analgesic & Antipyretic actions ONLY• why use APAP over ASA?

– Can be used in all ages (including children)– Rarely causes GI upset and bleeding– ok with anticoagulation medications

• Main disadvantage –liver damage w/ long term use, high dosages, or heavy alcohol use

• NMT (no more than) 3 grams (3000-mg) in 24 hours for adults with normal liver function!

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Non-steroidal Anti-inflammatory (NSAID’s)

• ibuprofen (Advil®, Motrin®), naproxen (Aleve®) • for mild to moderate pain• for inflammatory conditions, dysmenorrhea,

dental pain• S/E- GI … stomach upset, bleeding• Do not take with ASA, APAP or other NSAID’s.• Time limits: 10 days for pain, 3 days for fever or

as directed by MD

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World Health Organization (WHO) Pain Ladder

•Mild Pain- take APAP, ASA, or NSAIDS around the clock

•Moderate Pain- add mild opioid (codeine or hydrocodone)

•Severe Pain-D/C mild Opioid, give strong opioid (hydromorphone or morphine), while continuing the non-opioid. [a word about meperidine (Demerol)]

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Adjuvant Analgesic• Used to enhance analgesic efficiency and prolong effects of opioid

medications• Typically not prescribed alone for pain• Goal = Decreasing amount of pain medication while increasing

pain control• to reduce side effects of analgesics (ex: nausea)• Examples:

– Tricyclic Antidepressants (amitriptyline) *treat dull aches– Corticosteroids (prednisone) *treat inflammation– Anti-Convulsants (lorazepam, phenytoin, gabapentin) *treat sharp,

shooting, or burning pain– Antihistamines (hydroxyzine) *treat anxiety/nausea

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------ THANKS ------

Have a great week!

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