digoxin lanoxin lanoxicaps
Download
Skip this Video
Download Presentation
Digoxin (Lanoxin/Lanoxicaps)

Loading in 2 Seconds...

play fullscreen
1 / 16

Digoxin (Lanoxin/Lanoxicaps) - PowerPoint PPT Presentation


  • 188 Views
  • Uploaded on

Seth Adams Duy Cao Scott Davis Cheryl Hanslovan Bryan Ing Kristin McKay Vic Patel Dan Rackham Darren Smith Phong Vuong. Digoxin (Lanoxin/Lanoxicaps). foxglove digitalis. General Structure. Mechanism of Action.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Digoxin (Lanoxin/Lanoxicaps)' - yachi


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
digoxin lanoxin lanoxicaps

Seth Adams

Duy Cao

Scott Davis

Cheryl Hanslovan

Bryan Ing

Kristin McKay

Vic Patel

Dan Rackham

Darren Smith

Phong Vuong

Digoxin (Lanoxin/Lanoxicaps)

foxglove digitalis

mechanism of action
Mechanism of Action
  • Digoxin inhibits membrane bound sodium-potassium ATPase resulting in an increased intracellular [Na+] and thus an increase in the intracellular [Ca2+] by stimulation of Na+ and Ca2+ exchange.
  • Digoxin has an indirect effect on the sinoatrial and atrioventricular nodes (vagomimetic actions).
  • Baroreceptor sensitization also results from digoxin. This leads to increased afferent inhibitory activity and reduced activity of the sympathetic nervous system and renin-angiotensin system.
slide4

Digoxin

(-)

2

+

Ca

+

3Na

+

2K

NaCaX

ATPase

+

3Na

Ca2+

RyR

ATP

Ca2+

2

+

ATPase

Ca

SR

ADP

Contraction

net effect
Net Effect
  • Positive inotropic action (an increase in the force and velocity of myocardial systolic contraction).
  • A decrease in the degree of activation of the sympathetic nervous system and renin-angiotensin system.
  • Slowing of the heart rate and decreased conduction velocity through the AV node.
main clinical indications
Main Clinical Indications
  • Heart Failure
    • Increases cardiac output by positive inotropic actions
    • Therapeutic level of 0.5-1 mcg/L
  • Atrial Fibrillation
    • Rate control by vagomimetic actions
    • Therapeutic level of 0.5-2 mcg/L
available dosage forms
Available Dosage Forms
  • Tablets ( F = 0.6 - 0.7)
    • 125 mcg ( yellow, # Y3B ) or 250 mcg ( white, # X3A )
  • Capsules (Lanoxicaps) ( F = 0.9 – 0.95)
    • 50 mcg ( red, # A2C ) , 100 mcg ( yellow, # B2C ), and 200 mcg ( green, # C2C)
  • Pediatric Elixer ( F = 0.75 – 0.85)
    • 50 mcg per 1 ml (10% alcohol)
  • Injection ( F = 1.0 )
    • 250 mcg per 1 ml (1 ml ampule)
  • Pediatric Injection ( F = 1.0 )
    • 100 mcg per 1 ml (1 ml ampule)
side effects toxicities
Side Effects & Toxicities
  • Yellow/green visual changes, halos around light
  • N&V and diarrhea (50-75% of patients)
  • Bradycardia (75-90% of patients)
  • Fatigue, malaise, confusion, headache, etc.
  • Anorexia
drug interactions
Drug Interactions
  • Amiodarone
    • ↑[Digoxin] by 70%
  • Verapamil
    • ↑[Digoxin] by 50-75%
  • Propafenone
    • ↑[Digoxin] by 30%
  • Quinidine
    • ↑[Digoxin] by 50-75%
  • Erythromycin
    • ↑[Digoxin]
pharmacokinetic parameters
PharmacokineticParameters
  • Absorption
    • After oral dosing:
      • Onset of action in 0.5 – 2 hours
      • Peak effect reached in 2 – 6 hours
  • Distribution
    • Skeletal and heart muscle, but not into adipose tissue
    • Up to 25-30% is bound to plasma proteins
  • Metabolism
    • Follows first-order kinetics
    • Limited metabolism via sugar hydrolysis and lactone ring reduction
    • Half-life = 1-2 days
  • Excretion
    • 60-80% excreted unchanged in urine
    • Undergoes ACTIVE tubular secretion in the kidneys
clinical considerations
Clinical Considerations
  • Doses must be individualized and depends on the type & severity of the disease, age & weight of the patient, renal function, and concomitant disease states
  • Normal dosage range is 125 – 500 mcg (50 – 200 mcg capsules) a day in a single dose
  • Contraindications: Patients w/ ventricular fibrillation, renal impairment, hypokalemia, hypomagnesemia, hypercalcemia, and pulmonary disease
  • Patient must be advised not to take nonprescription cough or cold medications, antacids, laxatives, or antidiarrheals without consulting the pharmacist or physician
  • Pregnancy category C
digoxin equations
Digoxin Equations
  • IBW = 50 (or 45.5) + 2.3 x (inches over 60)
  • CrCl = ((140 - Age) x IBW) / (72 x SCr) ( x 0.85 for females)
  • Clearance Digoxin: Cldig = (0.8 ml/min/kg x IBW) + CrCl
    • w/ CHF: Cl = (0.33 ml/min/kg x IBW) + (0.9 x CrCl) (these values were multiplied by 0.06 to convert them from mL/min to L/hr)
    • w/ co-administration of amiodarone: Cl = 0.5 x Cl (without amiodarone)
  • Vd = 7.3 L/kg x IBW
    • w/ renal dysfunction: Vd = (3.8 L/kg x IBW) + (3.1 x CrCl)
  • LD = (Cp (desired level) x Vd) / (F)
  • MD = (Cp (desired level) x Cldig x Xo) / (F)
sample problems
Sample Problems
  • WB is a 75-year-old female with PMH including atrial fibrillation, type II diabetes, hypertension, and renal insufficiency. She is 5’4” and weighs 75 kg. Her SCr is 3.4 mg/dL. Calculate a loading and maintenance dose for Lanoxin tablets for Mrs. B.
    • Target Cpss = 1.0 mcg/L for atrial fibrillation
  • AS is a 78-year-old male with CHF. He is 5’10” and weighs 73kg. His SCr is 1.1 mg/dL. Calculate a dosing regimen using Lanoxicaps.
    • Target Cpss = 0.7 mcg/L for CHF
problem solutions 1
Problem Solutions - 1
  • WB w/ Renal Dysfunction:
    • IBW = 45.5 kg + 2.3 (4 in) = 54.7 kg
    • CrCl = ((140-75) x 54.7 kg (.85)) / (3.4 x 72) = 12.35 mL/min
    • Vd = (3.8 L/kg x 54.7 kg) + 3.1 (12.35 mL/min) = 246.15 L
    • Cldig= (0.8 mL/min/kg x 54.7 kg) + 12.35 mL/min = 56.11 mL/min = 3.37 L/hr
    • LD = (246.15 L x 1 mcg) / (0.7) = 351.64 mcg  Use 375 mcg tabs once
    • MD = Cpss = 1 mcg/L = (Xo(0.7)) / (3.37 L/hr x 24 hr)  0.7Xo = 80.88 mcg  Xo = 115.54 mcg  Use 125 mcg tabs qday
problem solutions 2
Problem Solutions - 2
  • AS w/ Congestive Heart Failure:
    • IBW = 50.0 kg + 2.3 (10 in) = 73 kg
    • CrCl = ((140-78) x 73 kg) / (1.1 x 72) = 57.15 mL/min
    • Vd = (7.3 L/kg x 73 kg) = 532.9 L
    • Cldig= (0.33 mL/min/kg x 73 kg) + 0.9 (57.15 mL/min) = 75.52 mL/min = 4.53 L/hr
    • LD = (532.9 L x 0.7 mcg) / (0.95) = 392.66 mcg  Use 400 mcg caps once
    • MD = Cpss = 0.7 mcg/L = (Xo(0.95)) / (4.53 L/hr x 24 hr)  0.95Xo = 76.1 mcg  Xo = 80.11 mcg  Use 100 mcg caps qday
references
References
  • 20th edition top 200 pharmacy drug cards. SFI Medical Publishing. 2004.
  • Class lecture. Pharmacy 750. 11/3/2005. Connie Covington
  • Tharp, R. (2006) Digoxin Dosing. Retrieved March 9, 2006 from the world wide web: http://www.rxkinetics.com/dig.html
  • Medicinal Plants. (2006) Digoxin Image. Updated Aug 12, 2005. Retrieved March 8, 2006 from world wide web: http://www.science.siu.edu/plant-biology/PLB117/Nickrent.Lecs/Medicine.html
  • Rx-List. (2006) Digoxin. Updated March 12, 2006. Retrieved March 8, 2006 from world wide web: http://www.rxlist.com/cgi/rxlist.cgi?drug=digoxin
  • Digoxin Structure. Retrieved March 8, 2006 from world wide web: http://medpharm.chunma.ac.kr/Aldja/CVS/cardiac_glycoside/img/digoxin_structure.GIF