Analgesics Flashcards
What is CNS Pharmacology?
How drugs alter brain activity and offset pathology
What is neuropharmacology?
how drugs act on neurons at cellular/molecular level
What is psychopharmacology?
how drugs modify behavior, perception, affect a thought
Why are Large Pharm companies restricting neuropsychiatric drug development efforts?
- Regrettably, recent developments are not that good: large pharm companies severely restricting neuropsychiatric drug development efforts citing
Low chances of successful CNS drug applications
What is a drug?
Drug: A substance used to prevent or treat conditions associated with stimulation or depression of the brain associated with both mental and physical processes
What is the therapeutic importance of drugs?
- Relieve pain and fever
- Suppress disorders of movement or seizures
- Induce sleep or arousal
- Reduce desire to eat
- Inhibit motion sickness
- Treat anxiety, mania, depression
What are prescription drugs?
Prescription Drug: A drug that is limited to use under the supervision of a veterinarian
because of potential danger, difficulty of administration, or other indications
What is a controlled drug?
Controlled Drug: Drugs that have a potential for abuse or dependence;
classified into schedules according to their level of abuse potential
What are CNS Stimulants?CNS Depressants?
Drugs can speed - up the transfer: CNS stimulants
Drugs can slow - down the transfer: CNS depressants
What do CNS drugs act on?
CNS drugs act on specific receptors that modulatecsynaptic transmission
What can alter synaptic transmission?
Some nonspecific agents (alcohol, anesthetics) have
non-receptor-mediated actions that result in
alterations in synaptic transmission
What are the effects of CNS drugs?
- Analgesia: narcotic (opioids) and non-narcotic (NSAIDs & NMDA receptor antagonists)
- Tranquilization (sedation) effects
- Anticonvulsant effects
- Antiemetic effects
- Anxiolytic, sedative, and hypnotic
- General anesthetic effects
- Behavior changes: CNS stimulants
CNS Depressants (antidepressants, anxiolytic drugs)
What are agonists? What are antagonists?
Agonists:
* Bind to and stimulate target tissue (CNS)
Antagonists:
* Bind to target tissue but don’t stimulate
What are the actions of CNS drugs?
Actions:
* Pharmacokinetics * Pharmacodynamics * Drug distribution * Target tissues and stimulation (CNS: depression or stimulation)
What are the sites and mechanisms of drug action?
What does each number correlate to?
What are the main targets for neuroactive drugs?
Main targets for neuroactive drugs:
Ion channels Receptors Enzymes Transport proteins
Most of the targets occur in several different________ ________, giving rise to subtle differences in ________ and pharmacology
Most of the targets occur in several different molecular isoforms, giving rise to subtle differences in function and pharmacology
Why is slowly developing secondary responses to primary drug interaction important?
- Slowly developing secondary responses to the primary interaction of the drug
with its target are often important (delayed efficacy of antidepressants,
tolerance and dependency with opioids)
What is the blood brain barrier? What is the function?
- The term BBB denotes the highly-selective barrier separating the brain tissue from the blood circulation * The main function is the protection of CNS against toxins, pathogens and even NTs (glutamate)
What is the composition of the BBB?
- The barrier consists of a continuous layer of endothelial cells joined by tight junctions and surrounded by astrocytes
For drugs to gain access to the brain, what must their characteristics be?
- DRUGS:
Small in molecular size (CO2, caffeine, nicotine, heroin)
Lipid soluble (lipophilicity)
Poorly bound to protein
Non-ionized at the pH of cerebrospinal fluid (CSF)
Diffusion or carrier-mediated transfer (L-DOPA)
Where does the BBB exhibit an increase in permeability?
- The BBB tends to increase in permeability in the presence of inflammation or at the site of tumor
What is important about the neonatal BBB?
- The BBB is poorly developed in neonates; hence, chemicals can easily gain access
to the neonatal brain
What are analgesic drugs used for ? What is the goal of therapy?
- Analgesic drugs are used to inhibit pain processing at different levels
- Goal of therapy: reduction of transduction, transmission, modulation, and perception of pain
What is pain?
Pain: is an unpleasant sensory and emotional experience associated with
actual or potential tissue damage. Pain has been recognized for its contribution to morbidity and mortality
What is the classes of pain dependent on?
- Duration: Acute Vs. Chronic
Location: Visceral vs Somatic, vs. neuropathic
What is acute pain? What is chronic pain?
Acute: sudden in onset, resolves in 1-3 days. initiates from traumatic insult well controlled with an analgesic
Chronic: slow in onset, persists for weeks/months altered homeostasis, long-term distress combination of potent analgesics
What does it mean if it was visceral pain? Somatic? Neuropathic?
What are the 4 parts of the pain processing system
What are examples of drug types that work on the 4 parts of pain processing?
What are opioids? Where can you find opium? What is the active chemical compond in opoioids
what are opiates?
What are opioids?
Waht are endogenous opioid neuropeptides?
What are the routes of administration for opioids? The half-lifes in dogs, cats, and horses? Safety margin? Pharmacokinetics?
What is the issue with cats metabolizing opioids?
Cats are deficient in the metabolic pathway, the t1/2 of most opioids in cats may be prolonged
What are the uses for opiod as an anelgesic? an preanesthetic?
What are opioids classified as? What can it produced when mixed with other compoinds?
What are the pharmacologic effects of opioids?
What is the method of action of opioids?
What are some commonly used opioid agonists?
Agonists
Morphine, hydromorphone, oxymorphone (10 times >), fentanyl (75-125 times > potent), tramadol (<)
What are some commonly used opioid partial agonists?
Buprenorphine, Butorphanol (µ-receptor)
What are some commonly used mixed opioid agonists- antagonists?
What are some antagonist opioids?
What kind of receptors are used for opioids? Where can they be found?
All opioid receptors are G-coupled receptors that mediate the inhibition of neurotransmission and endocrine secretion
The receptors are present in numerous cells/tissues including brain, spinal cord,
GI tract, urinary tract, and vas deferens in male reproductive system
What are the three opioid receptor subtypes?
3- receptor subtypes:
* µ-receptors: brain, spinal cord
Spinal and supraspinal analgesia, euphoria, mild sedation, miosis, respiratory depression, chemical dependence, inhibition of Ach and dopamine release, and a decrease in GI motility
- κ-receptors: cerebral cortex, spinal cord and other brain regions Spinal and supraspinal analgesia, sedation, dysphoria, diuresis, and miosis
- Δ-receptors: limbic system, cerebral cortex, and spinal cord
Spinal and supraspinal analgesia, inhibition of dopamine release, and cardiovascular depression
What are the adverse effects of opioids for the CNS, Cardiovascular, respiratory, and gi systems?
What are other adverse effects of opioids?
When. should you use opioid antagonists? What drugs you give? What route? What species?
- Emergencies: Reverse undesirable effects
CNS and respiratory depression
Overdose
Reverse neuroleptanalgesia
Reviving neonates delivered by C-section - Wake up patient following sedation
Naloxone hydrochloride
* IM or slow IV administration
* Dogs, horses, cats, exotic mammals
Naltrexone
* Used in wild animals (IV, IM against carfentanil effects)
* Orally in dogs for behavioral problems (constant licking, tail chasing)
What opioid antagonist is longer lasting?
Naltrexone
What is the pharmacokinetics of naloxone? What is the method of action?What are the adverse reactions?
What are NMDA receptor antagonists used for analgesic? What are the antagonists? What drugs are used for this? What are the ligands? What can it mediate?
What are non opioid analgesic drugs? What is another name for them? What drugs are used for this? What is the method of action? What is the side effects? What is this used for?
