CCP 109 Pharmacology Flashcards
Hydralazine indications
- Hypertensive emergency
2. Hypertensive emergency in pregnancy or postpartum
Hypertonic Saline 3% indications
Hyponatremia Intracranial hypertension (elevated ICP)
Nitroglycerin Infusion indications
mechanism of action, onset and duration
- relief from anginal chest pain
2. Reduction of blood pressure (preload) in acute cardiogenic pulmonary edema
Labetalol indications
Severe hypertension or hypertensive crisis
Norepinephrine indications
onset and duration
CCP: Symptomatic bradycardia
CCP: Shock with hypotension refractory to fluid resuscitation
CCP: Cardiogenic shock with refractory hypotension
Vasopressin indications
Vasodilatory shock
Dopamine indications
, contraindications, dosing, mechanism of action, onset and duration
- Symptomatic hypotension in the absence of hypovolemia (e.g., cardiogenic shock, bradycardia, sepsis, renal failure)
- Post-cardiac arrest hypotension
Hydralazine MOA
direct arteriole vasodilator
Causes direct vasodilation of arterioles, decreasing systemic resistance
May occur due to inhibition of calcium release from sarcoplasmic reticulum and inhibition of myosin phosphorylation in arterial smooth muscle cells
Hydralazine contraindications
Hypersensitivity to hydralazine
Coronary artery disease
Mitral valve rheumatic heart disease
Severe tachycardia and heart failure with high cardiac output
Myocardial insufficiency due to mechanical obstruction (aortic or mitral stenosis, constrictive pericarditis)
Isolated right ventricular heart failure due to pulmonary hypertension
Acute dissecting aortic aneurysm
Porphyria
Hydralazine dosing
CCP: Hypertensive emergency
10-20 mg IV/IM every 4-6 hours as required
CCP: Hypertensive emergency in pregnancy or postpartum
5-10 mg IV; may repeat 5-10 mg doses every 20 minutes if blood pressure continues to exceed thresholds
Consider alternative agent if blood pressure remains elevated after a total of 20-30 mg
Hydralazine pharmacokinetics (onset and duration)
Intravenous:
Onset: 5-20 minutes
Peak: 10-80 minutes
Duration: 1-4 hours
Hypertonic Saline 3% contraindications
Hypersensitivity
Hypernatremia
Fluid retention
Hypertonic uterus
Hypertonic Saline 3% dosing in Intracranial hypertension
5ml/kg IV bolus
Hypertonic Saline 3% mechanism of action in elevated ICP
- Hypertonic saline increases the osmolarity of the blood, which allows fluid from the extravascular space to enter the intravascular space, which leads to decreases in brain edema, improved cerebral blood flow, and decreased CSF production
Hypertonic Saline 3% pharmacokinetics (onset and duration) in elevated ICP
Onset: immediate IV
HTS causes a correction in the median subthreshold ICP by approx 148 min (~2 hours)
Nitroglycerin Infusion contraindications
Known allergy or hypersensitivity to nitroglycerin
Use of Viagra (sildenafil) or Levitra (vardenafil) within the previous 24 hours
Use of Cialis (tadalafil) within the previous 48 hours
Severe anemia
Restrictive pericarditis or pericardial tamponade
Documented right sided acute myocardial infarction
Hypotension or uncorrected hypovolemia
Nitroglycerin Infusion dosing
10-200 mcg/min IV infusion
Nitroglycerin Infusion mechanism of action
- Relaxes smooth muscle in vasculature.
- Nitroglycerin works primarily as a venodilator, but can also produce coronary and systemic arterial vasodilation (high doses >100mcg/min), decreasing preload and lowering myocardial oxygen demand.
Nitroglycerin Infusion pharmacokinetics (onset and duration)
Onset: 30 seconds - 1 minute (IV)
Peak: 3-5 minutes (IV)
Duration: 15-30 minutes (IV)
Labetalol contraindications
Known hypersensitivity to labetalol or any ingredient in the formulation
Bronchospastic airway disease
Obvious congestive heart failure
Second or third-degree heart block
Cardiogenic shock
Severe bradycardia
Other conditions associated with severe and prolonged hypotension
Labetalol dosing
For acute hypertensive events (emergent/urgent): 10- to 20mg IVP q10 minutes until the SBP is within the desired range or a maximum dose of 300 mg per 24-hour period is reached.
A continuous infusion can also be considered and initially started at 0.5 to 2 mg per minute with the potential to titrate up to 10 mg per minute.
Labetalol mechanism of action
contains both selective, competitive, alpha1-adrenergic antagonism and non-selective, competitive, beta-adrenergic (B1 and B2) blocking activity
Labetalol pharmacokinetics (onset and duration)
Intravenous:
Onset: 2–5 minutes
Peak:
5-15 minutes
Duration: 2–4 hours, although a longer duration of effect (i.e., up to 24 hours) has been reported in some patients
Norepinephrine contraindications
No absolute contraindications
Cautions:
Mesenteric or peripheral vascular thrombosis (avoid in patients with mesenteric or peripheral vascular thrombosis as the subsequent vasoconstriction will increase the area of ischemia and infarction)
Pregnancy (no human studies. animal models show potential for placental perfusion and induction of fetal bradycardia.)
Profound hypoxia (Profound hypoxia or hypercarbia can sensitize the myocardium to unstable arrhythmias, which could be exacerbated or even be initiated by the use of norepinephrine)
Hypovolemia (what are you gonna squeeze if the pipes are empty..? use only as an emergency measure for maintaining coronary or cerebral perfusion pressure while waiting for appropriate volume resuscitation)
Norepinephrine dosing
1-200mcg/min
Norepinephrine mechanism of action
sympathomimetic which is structurally identical to epinephrine but lacks a methyl group on its nitrogen atom. This makes it primarily agonistic at alpha1 and beta1 receptors, with little-to-no beta2 or alpha2 activity.
At low doses (<2 mcg/min), the beta1 effects may be more pronounced However, in doses >3 mcg/min, the alpha1 effects may predominate.
The increased activation of the alpha1 receptors will result in vasoconstriction and dose-dependent increases in SVR. The ratio of venous to arterial activity is relatively equal.
Norepinephrine pharmacokinetics (onset and duration)
Intravenous:
Onset: immediate
Peak: immediate
Duration: 1-2 minutes after infusion ends
Vasopressin contraindications
Hypersensitivity to vasopressin or any component
Vasopressin dosing
The 2016 Surviving Sepsis Campaign guidelines recommend a maximum vasopressin rate of 0.03 units/minute because higher rates may increase the risk of limb, digital, and mesenteric ischemia
≤0.03 units/minute IV. Titrate up by 0.005 units/minute at 10 to 15 minute intervals to a maximum dose of 0.1 unit/minute, if target blood pressure is not reached.
Vasopressin mechanism of action
- Vasopressin stimulates a family of arginine vasopressin (AVP) receptors, oxytocin receptors, and purinergic receptors.
- Vasopressin, at therapeutic doses used for vasodilatory shock, stimulates the AVPR1a (or V1) receptor and increases SVR and MAP; in response to these effects, a decrease in heart rate and cardiac output may be seen.
Vasopressin pharmacokinetics (onset and duration)
Intravenous:
Onset: 30-60 minutes
Peak: unknown
Duration: for duration of infusion and ~20 minutes after discontinuation
Dopamine contraindications
onset and duration
Known or suspected pheochromocytoma
Tachydysrhythmias
Patients taking mono-amine oxidase inhibitors (extreme caution required)
Dopamine dosing
2 mcg/kg/min IV: dopaminergic effects
5-10 mcg/kg/min IV: beta effects
10-20 mcg/kg/min IV: alpha effects
For the treatment of hemodynamically unstable patients, the dose range is 5-20 mcg/kg/min
Titrate DOPamine in increments of 2-5 mcg/kg/min every 2-5 minutes to effect
Dopamine mechanism of action
DOPamine’s activity is dose-dependent:
- low doses result in renal, mesenteric, and cerebral vasodilation, improving urine output (and are very unlikely to be used in out-of-hospital care).
- Medium doses provoke beta stimulation, increasing heart rate and contractility.
- At high doses, alpha effects dominate, producing systemic vasoconstriction.
Dopamine pharmacokinetics (onset and duration)
Intravenous:
Onset: 2-5 minutes
Peak: unknown
Duration: < 10 minutes
Propofol indications
- Induction of general anesthesia in patients ≥ 3 years old
- Sedation during monitored anesthesia care for patients undergoing procedures
- Sedation in intubated, mechanically-ventilated ICU patients
Propofol contraindications
Hypersensitivity to Propofol or any component of the formulation: eggs or egg products, soybeans or soy products
Pediatrics <3 years of age
Patients in third trimester of pregnancy
Caution: Hemodynamic instability
Propofol dosing
Doses based on total body weight
Induction: 1-2.5mg/kg healthy adults OR 0.5-1 mg/kg in hypotensive adults
Maintenance: 25-100 mcg/kg/min
Propofol mechanism of action
- GABA-A agonist
2. reduced glutamateric activity through NMDA receptor blockade
propofol pharmacokinetics (onset and duration)
Onset: Anesthetic: Bolus infusion (dose dependent): 9 to 51 seconds (average 30 seconds)
Duration: 3 to 10 minutes depending on the dose, rate and duration of administration
Distribution: Large volume of distribution; highly lipophilic
Metabolism: Hepatic
Half-life: 40 minutes
Phenytoin indications
Seizures refractory to midazolam
Phenytoin contraindications
Sinus bradycardia, sinoatrial block, 2nd or 3rd degree AV block, Adams-Stokes syndrome, QT interval prolongation, or other heart rhythm disorders
Hypersensitivity to phenyTOIN or other hydantoins
Hypersensitivity to propylene glycol or ethanol
Concurrent sodium channel poisoning or toxic ingestion (cyclic antidepressants, cocaine, etc.)
Phenytoin dosing
20 mg/kg IV/IO - dilute to a concentration of 10 mg/mL or less and infuse based on body weight:
For patients < 75 kg: administer over a minimum of 30 minutes
For patients 75-150 kg: administer over a minimum of 60 minutes
For patients > 150 kg: administer over a minimum of 90 minutes
Do not repeat administration
Phenytoin mechanism of action
- Stabilizes neuronal membranes and decreases seizure activity by lowering intracellular sodium levels in the motor cortex;
- prolongs effective refractory period and suppresses ventricular pacemaker automaticity, shortening action potential in the heart.
phenytoin pharmacokinetics (onset and duration)
Intravenous:
Onset: 30 minutes - 1 hour
Peak: 1-2 hours
Duration: 24 hours
