Drug Box 4 Flashcards
Hydralazine Name
Apresoline
Hydralazine Classification
Arteriolar Dilator
Hydralazine Contraindication
Not recommended for patients with myocardial ischemia or coronary disease.
Hydralazine Dose and Route
Bolus Infusion 5-20 mg
IV
Hydralazine MOA
Hydralazine is a direct systemic arterial vasodilator which both hyperpolarizes smooth
muscle cells and activated guanylate cyclase to produce vasorelaxation
Hydralazine Elimination
Metabolized by GI mucosa and liver by N-acetyltransferase.
Hydralazine Onset
5-20 mins
Hydralazine Peak
15-30 mins
Hydralazine Duration
2-8 hrs
Hydralazine Misc
Long-term hydralazine is associated with a systemic lupus syndrome
Pitocin Name
oxytocin
Pitocin Classification
synthetic pituitary hormone/lactation stimulant
Pitocin Contraindication
-Use with caution with other vasoactive drugs—Modern preps are pure-–No vasoconstriction w/ other sympathomimetics
-Rapid infusion: transient systemic hypotension due to relaxation of vascular smooth muscle, reflex tachycardia
-Nasal preparation is contraindicated in pregnancy
Side Effects: hypersensitivity leading to uterine hypertonicity, tetanic contractions, uterine rupture, arrhythmias, N/V, SAH, water intoxication, seizures from water intoxication, hyponatremia, neurological dys.
-Uterine atony is the most common cause of severe postpartum hemorrhage.
-Reflex tachycardia and increase in CO accompany a decrease in BP
-2nd dose = decreased hemodynamic effects compared to initial dose
-Prior oxytocin exposure: downregulation and desensitization = risk for PP hemorrhage and atony
-Marked decrease in BP in: blunted compensatory reflexes (anesthesia) and hypovolemic pts
Pitocin Dose and Route
A dilute solution (10mU/mL) by contin. infusion: 1-2 mU/min (increased 1-2 q15-30 min until uterine contractions q2-3 min)
Average to induce: 8-10 mU/min
Up to 40 mU/min: uterine atony post delivery
IM: used to provide sustained contractions postpartum
Prevent atony: 1-3 International units over 30 seconds-–may need phenylephrine
Management of atony/PP hemorrhage: 3-5 IU over 30 seconds
(Flood pg. 772)
Route
IV, IM, & Nasal
Pitocin MOA
Binds to G proteins on the surface of uterine myocytes to trigger the release of calcium from the SR, exerting a contracting effect on the pregnant uterus. Oxytocin also augments the AP of the uterine smooth muscle.
- Stimulates the contraction of myoepithelial cells of the breast for milk ejection.
- Transported down the pituitary stalk by axoplasmic flow to the posterior pituitary nerve. The nerve impulses will stimulate the release of oxytocin into nearby blood vessels and transport oxytocin to the target sites
Pitocin Elimination
Tissue Metabolism; Renal Elimination
Pitocin Onset
Onset
IV: immediate
Nasal: a few minutes?
IM: 3-5 minutes
Pitocin Peak
IV: < 20 minutes
Nasal: Unknown
IM: 40 minutes
Pitocin Duration
Duration
IV: 20-60 minutes
Nasal: 20 minutes
IM: 2-3 hours
Pitocin Misc
Oxytocin exhibits a slight AVP-like activity when administered in high doses. This can cause water intoxication, hyponatremia, and neurologic dysfunction if an excess volume of fluid is administered. The risk of complications are REDUCED if you infuse an electrolyte-containing solution rather than glucose in water
Methylene Blue Name
ProvayBlue
Methylene Blue
Classification
Treatment for methemoglobin (Flood, 298 hardcover) \ Cyanide toxicity treatmentt
Methylene Blue Dose
4. Dose- Treatment of methemoglobinemia is 1-2mg/Kg IV over five minutes (total dose should not exceed 7-8 mg/kg) (Flood, page 298 hardcover) Continuous infusion (after initial dose) of 0.25mg/kg/hr for 48-72 hours is recommended with a maximum dose of 7 mg/kg (Nagelhout, page 219 electronic) 5. Route- IV only mentioned
Methylene Blue
MOA
- Methylene blue is reduced to leukomethylene blue, which then acts as an electron donor and nonenzymatically reduces methemoglobin to hemoglobin. (Flood, page 298 hardcover)
- It is also believed to interfere with the nitric oxide (NO)-cyclic guanylate monophosphate (CGMP) pathway, inhibiting the vasodilation effects of smooth muscle. (Nagelhout, page 219 electronic)
Methylene Blue
Elimination
Elimination- Clearance from the blood plasma is 60 minutes. (Flood, 298 hardcover)
Methylene Blue
Onset
20 min
Methylene Blue peak
20-60 min
Methylene Blue Duration
60 mins
Heparin Classiciation
Anticoagulant
Heparin Contraindication
peptic ulcer; esophageal varices; arterial aneurysm; GI or urinary tract malignancy; vascular retinopathy; recent liver/renal biopsy; acute pericarditis; threatened abortion; infective endocarditis; recent regional anesthesia; severe HTN; recent CVA; recent surgery; trauma to the brain, eye, or spinal cord. Not be given IM.
Heparin Dose and Route
Dose: individualized based on the patient and the reason for anticoagulation (Nagelhout handbook, p. 645)
For prophylaxis (hip surgery, afib, valve disease): ratio of PTT to baseline PTT should be 1.2-1.5; For prosthetic heart valves, DVT, PE, recurrent embolism: 1.5-2
For CABG: Maintain ACT of 400-800 seconds
Initial IV Bolus: 350-500 u/kg
100 u/kg to be given hourly starting two hours after initial bolus
Prophylactic/Low dose SC therapy: 5000 units SC q. 8-12 hrs (obtain baseline PTT to determine bleeding complications)
Continuous IV infusion:
Loading dose: 70 u/kg (3000-10,000 u)
Maintenance dose: continuous infusion of 13-16 u/kg/hr (750-1300 u/hr)
Route: IV or subcutaneous (Flood, p. 648)
Heparin MOA
Accelerates the rate at which antithrombin (previously known as antithrombin III) neutralizes thrombin and factors VII, IX, X, and XI.
Anticoagulation depends on the presence of adequate amounts of antithrombin.
Heparin Elimination
Precise pathway of elimination is unknown (Flood, p. 648)
Elimination half-life = 1-2 hours in health adults
Heparin Onset
IV: immediate
SC: 20 mins - 2 hours
Heparin Peak
Over the range of heparin concentrations used clinically, the dose response relationship is not linear for multiple reasons
Heparin Duration
half-life and duration increase with increasing doses; prolonged in liver and renal disease
Heparin Misc
Monitor PTT (goal is 1.5-2.5x normal values, typically 30-35 secs) (Flood, p. 648) D/c IV Heparin infusion 4-6 hours before regional/neuraxial anesthesia administration
Protamine Sulfate Classification
Heparin antagonist
Protamine Sulfate Contraindication
Patients with sensitivity to fish who have previously received either protamine or insulins containing protamine at higher risk for hypersensitivity. If used in these patients, pretreat with corticosteroid or antihistamine
Protamine Sulfate Dose
Dose: 1 mg of protamine for every 100 units of heparin; Administer slowly IV over ten mins, do not exceed 50 mg (Nagelhout Handbook, p. 689) (Flood, p. 650)
Route: IV
Protamine Sulfate MOA
Positively charged alkaline protamine combines with the negatively charged acidic heparin to form a stable complex that is devoid of anticoagulant activity
Protamine Elimination
Clearance of protamine by the reticuloendothelial system (within 20 minutes) is more rapid than heparin clearance and that may explain, in part, the phenomenon of heparin rebound (Flood, p. 650)
Heparin has a half life of approximately one hour
Protamine Onset
Within 5 mins
Duration
2 hours
Misc
Anesthetic considerations- rapid IV injection is associated with hypotension, bradycardia, and flushing. A paradoxical effect may occur with doses greater than 100 mg
Xanax name
Alprazolam
Xanax classification
Benzodiazepine
Xanax contraindications
Known hypersensitivity to benzodiazepines, use of CYP3A4 protease inhibitors, pregnancy, taking ketoconazole and itraconazole, acute narrow angle glaucoma
Xanax dose
0.25-2 mg
Xanax route
PO
Xanax MOA
The exact mechanism of action for Xanax is unknown, however since it is a benzodiazepine one can expect it enhances the affinity of GABA A receptors for GABA→ increases chloride ions within the cell, hyperpolarizes the cell
Xanax Elimination
Liver
Xanax onset
1-2 hr
Xanax Peak
1-2 hr
Xanax Duration
12-15 hr
Ativan name
lorazepam
Ativan Classification
Benzodiazepine
Ativan Contraindication
post-op sedation (delayed emergence and prolonged amnestic effects), induction of anesthesia, mechanical ventilation (delayed weaning)
Ativan Dose and route
Dose: IV: 1-4 mg PO: 50 mcg/kg (Max 4 mg) (Flood p. 180)
Route: IV or PO
Ativan MOA
Enhance the affinity of the receptors for GABA which increases chloride conductance resulting in hyperpolarization of the post-synaptic membrane
Ativan Elimination
Metabolized in the Liver and 80% excreted in urine (Flood p. 180) 10-16 hrs
Ativan Onset
1-2 mins
Ativan Peak
20-30 mins
Ativan Duration
6-10hrs
Ativan Misc
more potent sedative and amnestic than other benzos (Flood p. 180) , low lipid solubility → slower onset and elimination
Albuterol names
Salbutamol
Albuterol Classification
Beta 2- adrenergic agonist; Short-acting, Inhaled adrenergic agonist
Albuterol Contraindications
allergy to Beta adrenergics; use with caution in QT prolongation
Albuterol Dose and route
Dose:
ORAL MDI: 2 Puffs (90 micrograms per puff) during slow, deep inhalation 1-5 minutes apart; repeated every 4-6 hours. Do not exceed 20 puffs/day.
Oral Nebulizer: 2.5-5mg every 15mins x 3-4 doses; followed by hourly tx during the initial hours of therapy.
Route: Oral (MDI, Inhalaled), PO, SQ, IV
Albuterol MOA
Beta 2 agonists relax bronchioles by binding to Beta 1 adrenergic -receptors of smooth muscle, epithelial, and endothelial cells. This stimulates G protein to activate adenylate cyclase converting ATP into cAMP
Albuterol Elimination
“The majority 80-100% of albuterol is excreted in the urine; its primary metabolic route is sulfate conjugation by sulfotransferase 1A3
Albuterol Onset
5-15min
Albuterol Peak
30-60 mins
Albuterol Duration
3-6 hours
Albuterol Misc
Key SE is tremor. Inhaled Albuterol (4 puffs) blunts airway responses to tracheal intubation in asthmatic patients. Large doses may cause tachycardia and hypokalemia
Ofirmev Name
Acetaminophen, Paracetamol
Ofirmev Classification
Non-opiod analgesic, Antipyretic
Ofirmev Contraindication
Hepatotoxicity in individuals with impaired liver function. Hepatotoxicity seen in chronic alcoholics. Overdose antidote is acetylcysteine.
Ofirmev Dose and Route
- ) Dose: Administer over 15 minutes. Adult dose>50kg, 1gm, q 4-6 hrs not to exceed 4g/day. Adult <50kg, 15mg/kg q4-6 hrs not to exceed 3gm/day. Ped >33kg, 15mg/kg q4-6 hrs not to exceed 2g/day. 2 gm/day for chronic alcoholics. Barash pg. 1578. Flood pg 274
- ) Route: Intravenous
Ofirmev MOA
Mechanism of Action (MOA): It has a central analgesic effect that is mediated through activation of descending serotonergic pathways. It also produces inhibition of prostaglandin synthesis. Spinal cord level it antagonizes neuro transmission by N-methyl-D-asparate substance P, (NMDA) and nitric oxide pathways
Ofirmev Elimination
it is eliminated by hepatic elimination by conjugation to either the glucuronide which is (55%) or sulfate which is (25%) less than 10% is oxidized by CYP2E1, 3A4 and isozymes to N-acetyl-p-benzoquininone (NAPQ1) metabolite. Which is excreted by the kidney at 1-4%.
Ofirmev Onset
8.) Onset: 150 seconds, IV or 2.5 minutes. 15-30 minutes IM, IV.
Ofirmev Peak
2hrs
Ofirmev Duration
2-6 hours
Lovenox Name
Low Molecular Weight Heparin, Enoxaparin
Lovenox Classification
anticoagulant
Lovenox Contraindication
renal patients
Lovenox Dose and Route
Dose - After surgery → 30-40mg subq Q12hrs. → prevent DVT or PE.
1mg/kg subq Q 12hrs→ unstable angina or Q-wave MI. (Nagelhout Handbook pg 634)
5.) Route SubQ
Lovenox MOA
Factor IIa & Xa antagonist (indirect)
Lovenox Elimination
4.5hr
Lovenox Onset
20-60 mins
Lovenox Peak
3-5 hrs
Lovenox Duration
12 hrs
Lovenox Misc
removal of indwelling catheters or central axis blocks (Nagelhout Handbook pg 634)& Surgery should be delayed 12 hours post last dose of drug- longer with renal patients. (flood, pg 650)
