Oral: Opioids Flashcards
MOA: Opioids in general
Activates Mu1, Mu2, Kappa & Delta receptors located on the peripheral ends of primary afferent neurons to directly ⬇transmission or inhibit the release of neurotransmitters, thereby altering the pain threshold, pain perception, and inhibiting ascending pain pathways.
Opioids mimic endogenous substances at the receptors: presynaptic: ⬇ neurotransmitter release;
postsynaptic: hyperpolarize the neurons by ⬆ K conductance.
Side Effects: That apply to all opioids
Miosis, drowsiness, N//V/C (CRTZ), urinary retention, SOO spasm, pruritis;
⬇CBF, ICP if hypoventilation is prevented, ⬇response to CO2 and hypoxia;
DD resp depression, ⬇chest wall compliance, cough suppression,
⬇catecholamine release and cortisol;
Class: Morphine
Phenanthrene alkaloid natural opioid agonist
Prototype
Pharmacokinetics: Morphine
30% PB; 23% non-ionized; low lipid solubility
Onset = <5 min; peak 15-30 min
DOA = 3 hrs
E1/2t = 3 hrs
Hep + Renal Met
Active metabolite = morphine-3 glucoronide (less active) and morphine-6-glucoronide (650x more potent)
Excreted in urine as M3G – 1-12% unchanged + feces
Side Effects: Morphine
Histamine;
dose dependent⬇HR, BP, SVR, CO;
delayed resp dep in spinal and epidurals d/t low lipid solubility;
tolerance, dependence
⬇CBF, ICP;
⬇ CO2 response curve and shift to right;
inhibits SA/AV node, causing brdycardia;
urinary retention, pruritis, SOO spasm, N/V/C;
Contraindications: Morphine
Allergy, asthma, COPD, bronchospasm,
synergistic resp dep w/ benzos + other sedatives,
dec dose in renal dz, peds + elderly
⬇dose in RF, only give one (accumulation)
Dose: Morphine
IV: usually 2.5-15mg Q 3 – 4 hrs
Anes: 2 mg/kg
Gtt: 1 – 10 mg/hr
Class: Meperidine (Demporol)
phenyl-piperidine synthetic opioid agonist (w/an atropine-like structure)
MOA: Meperidine (Demporol)
Mu and Kappa receptors
Pharmacokinetics: Meperidine (Demporol)
60% PB; 10% non-ionized, low/moderate lipid solubility Onset < 1 min, Peak: 5 – 10 min DOA = 3 hrs E1/2t = 3 hrs
normeperidine- longer acting (e1/2t 15-20 hrs) and 1/2 as potent as parent; can cause sz, confusion, hallucination, myoclonus
65% pulmonary 1st pass effect; liver metabolism to normeperidine and excreted in urine
Side Effects: Meperidine (Demporol)
histamine; sz; direct myocardial dep; mouth dry; ⬇shivering; dependence, tolerance;
urinary retention, N/V/C;
respiratory depression;
Contraindications: Meperidine (Demporol)
Fatal interaction with MAOIs;
metabolites accumulate with RF;
careful in CV, neuro disease, sz, asthma
Dose: Meperidine (Demporol)
IM/SQ/PO: 50 – 100 mg
IV: 25 – 75 mg
Shivering: 12.5 mg
Do not exceed 1 g/24 hrs.
1/10 potency of morphine
Class: Fentanyl, Sufentanil, Remifentanyl, Meperidine (Demporol)
phenyl-piperidine synthetic opioid agonist
Pharmacokinetics: Fentanyl
80% PB; 8.5% non-ionized; high lipid solubility Onset: 2 min; DOA 30-60 min E1/2t: 3-6 hrs; ctx sen 1/2t: 4.5 hrs "longest context sensitive 1/2 time of all the opioids***"
Min. active metabolite: Norfentanyl
75% pulmonary 1st pass effect; liver metabolism and excreted in urine
100x potency of morphine
Side Effects: Fentanyl
pruritus (“fentanyl nose itch”- even though no histamine release);
⬇HR, BP, SVR, CO;
sz-like activity;
wooden chest syndrome;
N/V/C, SOO spasm;
resp dep;
Contraindications: Fentanyl
brady arrhythmias, liver disease, RF, head trauma, synergistic resp dep w/ bdzs + sedatives
dec dose in renal dz, peds, elderly
Dose: Fentanyl
IV: 1 – 3 mcg/kg
Premed: 25 – 100 mcg
Intraop: 12.5-100 mcg
TOTAL:
1-10 mcg/kg if extubation is planned;
5-50 mcg/kg if to remain intubated;
Pharmacokinetics: Sufentanil
93% PB; 20% non-ionized; highest lipid solubility Onset 2 min; DOA 30 min E1/2t: 2.5 hrs; ctx sen 1/2t: 30 min
Active metabolite: Desmeth-sufenanil (1/10 as potent)
60% pulmonary 1st pass effect; liver and sm. intestine and excreted in urine 1% unchanges
1,000x potency of morphine
Side Effects: Sufentanil
⬇HR, BP, SVR, CO, cardiac arrest;
potent resp depressant, apnea, bronchospasm;
wooden chest/muscle rigidity;
dependence, tolerance
SOO spasm;
N/V/C, urinary retention, pruritus;
Contraindications: Sufentanil
asthma, allergy, airway obstruction;
⬇dose in elderly and hypovolemia
Dose: Sufentanil
analgesia boluses of 0.1-1 mcg/kg.
anesthesia:
dep on procedure*: 1-8 mcg/kg;
sole anesthesia: 8-50 mcg/kg
Class: Alfentanyl
tetrazole fentanyl derivative synthetic opioid agonist
Pharmacokinetics: Alfentanyl
90% PB; 90% non-ionized; high lipid solubility Onset: 2 min; DOA: 30-60 min E1/2/t: 1.5hr; Ctx Sen 1/2t: 1hr
Elimination: liver and sm. intestine; leaves the plasma in 30 min
10-20x potency of morphine
Side Effects: Alfentanyl
⬆ICP, slowing of EEG; no change in SVR or CO; skeletal muscle rigidity; ' respiratory depression; SOO spasm, N/V/C, pruritus
Contraindications: Alfentanyl
untreated parkinsons, ⬆ICP, respiratory depression
Dose: Alfentanyl
Induction: 50-200 mcg/kg; analgesia: 5-30 mcg/kg
Class: Remifentanyl
phenyl-piperidine synthetic opioid agonist with ester link
MOA: Remifentanyl
selective for Mu Receptors
Pharmacokinetics: Remifentanyl
80% PB; 67% non-ionized; high lipid solubility Onset: 2 min DOA: 10 min E1/2t: 10min; Ctx sen 1/2t: 4 min
Elimination: metabolized by tissue plasma esterases
100x potency of morphine
Side Effects: Remifentanyl
Dose dep ⬇HR, BP;
resp depression;
N/V/C, SOO spasm, pruritus
Contraindications: Remifentanyl
high doses = dec CMRO2 + CBF do not use in epidurals/spinals (d/t glycine prep); allergy; caution in elderly; preg class C
Dose: Remifentanyl
Initial: 0.5-1 mcg/kg (over 30-60sec);
infusion: 0.05-2 mcg/kg/min;
additional bolus: 0.1-1 mcg/kg
NOT FOR INDUCTION
