Medications Flashcards
Benzodiazepines
- MOA
- Characteristics
- Systemic effects
- Metabolism
- Reversal
- Bind to inhibitory GABA receptors in brain (cerebral cortex), increasing inward Cl- flow–> hyperpolarization and reduction in neuronal transmission.
- Sedation, anxiolysis, anterograde amnesia, muscle relaxant, anticonvulsant, NO analgesia
- Decrease BP and HR, large bolus can induce unconsciousness and apnea. Small doses can cause respiratory depression
- Metabolized via hepatic enzymes, some clinically active. Excreted by kidney.
- Flumazenil is reversal agent, can combat paradoxical excitement, excessive sedation and respiratory depression
Diazepam
–Valium (Benzo)
Highly lipid soluble, carried in organic solvent (propylene glycol or soybean oil emulsion. Injection can be painful. Numerous active metabolites and longer elimination time (t1/2 is 24-96H). Metabolites are partially eliminated in bile, may have recurrent effects with fatty meals.
Midazolam
– Versed (Benzo)
Lipid soluble, able to be delivered in a aqueous acidic solution (less pain on IV/ IM administration). 2-3X more potent than Diazepam with faster onset, elimination and decreased lingering effects. Minimal active metabolites. Monitor for respiratory depression.
Lorazepam
–Ativan (Benzo)
Long acting benzo with slow onset. Commonly given night prior to surgery for pre-op anxiolysis. Metabolized via glucuronidation with no active metabolites (does not use CYP-450). Excellent emergency anticonvulsant.
Triazolam
–Halcion (Benzo)
Sleep adjunct used for off label anxiolysis and moderate sedation. Only oral form available. Very short acting (~2 hours).
Remimazolam
–Byfavo (Benzo)
Ultra short acting benzo. undergoes hydrolysis via tissue esterase’s.
Flumazenil
–Anexate, Lanexat, Mazicon, Romazicon
Competitive antagonist for benzo reversal of sedation, disinhibition and respiratory depression. Given at 0.2 mg initially followed by 0.1 mg at 1 min intervals up to 1 mg. Emergency dose 0.5-1 mg bolus. Effects last 30-60 min and may require redosing (other drugs may out last flumazenil). Caution with epileptics who are on chronic benzo use.
Opioids
- MOA
- Characteristics
- Systemic effects
- Metabolism
- Reversal
- bind to opioid receptors. Agonistic activity modifies or decreases neuronal transmission of pain signals. Mu (u) and Kappa (k) receptors are predominately responsible for analgesia (1* u)
- analgesia and augmentation of sedation and euphoria. NO amnesia, sedation, or LOC.
- Respiratory depression/ arrest is most common side effect and can be exasperated with benzos, barbiturate’s, Propofol and other opioids. Bradycardia due to centrally mediated vagal response at higher doses. Suppress cough reflex, caution with asthmatic patients due to possible histamine release, resulting in decreased BP 2/2 vasodilation, pruritus and erythema. Other effects N/V, constipation, urinary retention, biliary tract spasm (may be misinterpreted as an allergic rxn)
- Most opioids are metabolized via hepatic enzymes and excreted into bile and urine. *** exception is Remifentanil, which is metabolized by plasma esterase’s
- Naloxone is reversal agent
Morphine
–Morphine (Opioid)
Poor lipid solubility–> slow onset. Effects last 3-4 h. Commonly used for post-op pain over procedural sedation. Histamine release can cause flushing and decreased BP. Metabolized by hepatic enzymes into two metabolites eliminated by kidney. Caution if compromised renal fxn.
Hydromorphone
–Dilaudid, Exalgo (Opioid)
A keytone derivative of morphine with a more rapid onset (2-5 min). x8 more potent than morphine (i.e. 1.2 mg = 10 mg morphine). No histamine release and no active metabolites
Meperidine
–Demerol (Opioid)
Synthetic opioid with rapid onset and 2-3 h duration. Used for post-op pain and Iv sedations. Active metabolite (normeperidine) that is potentially toxic to CNS. Post sedation delirium possible, especially in elderly. Accumulation of normeperidine in renally compromised pts may lead to seizures. Mixed with MAO-i it may cause serotonin Sx. Associated with significant histamine release. Not associated with bradycardia, may cause an INCREASE in HR, possible xerostomia. Rarely used in USA unless for post-op shivering (against k receptor).
Fentanyl
–Fentanyl (Opioid)
A synthetic opioid with high lipid solubility and high potency. Rapid onset (~1 min) and short duration of action (10-20 min). Does not induce histamine release, so no vasodilatory or bronchospastic effects. More pronounced bradycardia than morphine. Potent respiratory depressant. Possible chest wall and glottic rigidity (tx with naloxone or paralytic’s)
Remifentanil
–Ultiva (Opioid)
Synthetic fentanyl derivative. Rapid duration and extremely short duration of action (decreasing recovery time). Metabolized by nonspecific plasma esterases, clearance is rapid and independent of both renal and hepatic functions. Due to short duration of action, this will offer NO post-op pain control, must supplement with something. Possible “remifentanil-induced hyperalgesia” due to acute withdrawn of medication. Potent respiratory depression and may cause chest wall rigidity,
Naloxone
–Narcan
Pure opioid antagonist active at all opioid receptor subtypes. Reversal of both ventilatory depressive and analgesic effects. Can also reverse chest wall and glottic rigidity. Use with caution if pt is on chronic opioids (pain management/ illicit use or methadone), may result in acute withdrawals or acute congestive HF. Initial dose is 0.4-2 mg IV or titrated in0.04 mg increments. Duration of action is 30-45 min, so watch for reemergence of respiratory depression.
Propofol
–Propofol (Sedative)
Highly lipid soluble suspension in soybean oil, glycerol and egg phosphatide (egg protein is lecithin, most allergies are to egg albumin). Thought to act on GABA receptor. High doses can cause amnesia and LOC, also an anticonvulsant. 1.5-2.5 mg/ Kg for induction. In OMFS 10-30 mg bolus are given. Commonly used in conjunction with Benzo’s and opioids. Metabolized by hepatic enzymes, however rate of clearance exceeds hepatic blood flow. May decrease systemic BP by 20-40%. Blocks sympathetic tone allowing parasympathetic tone to dominate, blunting reflex tachycardia. Causes dose dependent respiratory depression. No histamine release. Rapid wake up with less CNS effects, possible euphoria on wake up. Decreased PONV. Due to large size of molecule, pain present when injected into smaller vessels. If open discard after 12 hours. EDTA is used in medication as antibacterial, may exasperate sulfite sensitives. No reversal agent.
