Foxglove

1
Foxglove

• Leilonie, Vicky, Katherine, Tony

2
The Question

• Purple foxglove is a common garden plant. Lois
  grows it alongside the chamomile she uses to make
  her herbal tea. She adds some of the foxglove to
  her tea, as she has heard it may have medicinal
  properties. In fact, ingredients in foxglove are
  used to treat some heart conditions. However,
  soon after drinking her concoction, she develops
  serious problems. Describe the action of the
  ingredient used in prescription drugs, why they
  are used, and what happens in an overdose (as in
  Lois case).

3
What is Foxglove?

• Referred to as Dead Mans Bells, Witches
  Gloves.
• Foxglove refers to their ability to fit over
  fingers.
• Entire plant poisonous, including the roots and
  seeds.
• Leaves of upper stem very potent (just a nibble
  can potentially kill you!)

4
Medicinal Use

• Digitalis purpurea
• Digitalis lanata (a.k.a wooly foxglove or Grecian
  foxglove) is the most commonly used plant for
  medications.
• Digitalis is the term for preparations containing
  digoxin.
• Low therapeutic index. (Medicinal amount is
  really close to the amount thats fatal).
• LD50/ED50 (lethal dose/effective dose for 50 of
  the population. Other medications with a low
  therapeutic index include lithium carbonate,
  dimercaprol).
• Herbalists have abandoned using the drug because
  it is hard to measure the amount of active drug
  in the solutions and because of the low
  therapeutic index.

5
What is Digoxin?

• Digoxin is a substance found in the digitalis
• Digoxin is a purified cardiac glycoside which
  comes from the foxglove plant (or digitalis)
• Used to treat heart conditions including atrial
  fibrilation, atrial flutter and congestive heart
  failure
• these cant be well controlled with other meds
• Was used to treat epilepsy and seizure disorders

6
Digoxin Details

• Digitalis inhibits the Na/K ATPase, resulting
  in an increased intracellular concentration of
  Na and passively increases levels of Ca2.
  Positive inotropic effects (increased force in
  muscle contractions).

• The force of contractions in the atria and
  ventricles arent matched Also has a vagal effect
  on the parasympathetic nervous system is used in
  re-entrant cardiac arrhythmia and to slow the
  ventricular rate during artial fibrillation.
• Not effective w/ a high sympathetic nervous
  system drive (those who are acutely ill, or
  during exercise).

7
Adverse Effects

• Loss of appetite
• Nausea
• Vomiting
• Diarrhea
• Blurred vision
• Confusion, drowsiness, nightmares, wild
  hallucinations
• Amnesia, psychosis
• Irregular and slow pulse
• Side effects stronger in those with low potassium
  levels (hypokelemia), digoxin competes w/ K ions
  on the Na/K ATPase pump (if youre low, its
  easy for digoxin to come in an take its place.)

8
What happened to Lois?

• Maybe she confused with the comfrey plant, which
  is brewed into tea and is safe.
• She used a dangerous amount of the plant by
  brewing it into her tea.

9
Analogy Fudge

• Doesnt it look good? (Just like the foxglove
  plant!)
• When you eat moms super rich triple peanut
  butter fudge, you can have only have a bit.
• You keep saying Oh, Ill have a little bit
  more
• But too much can make you really sick!

10
James Bond

• http//www.youtube.com/watch?vDtYX53UgSV8

11
References

• http//www.botanical.com/botanical/mgmh/f/foxglo30
  .html
• Lip, G. Y. H. , Watson, R. D. S., Singh, S. P.
  (1995). ABC of Atrial Fibrillation Drugs For
  Atrial Fibrillation. BMJ. 3111631-1634.
  http//www.bmj.com
• Barry, W.H., Hasin, Y., Smith, T.W. (1985).
  Sodium pump inhibition, enhanced calcium influx
  via sodium- calcium exchange, and positive
  inotropic response in cultured heart cells.
  Circulation Research. 56231- 241.
  http//circres.ahajournals.org
• Encyclopedia Britannica, http//www.britannica.com
  /
• Janice Lapsansky