Basic Pharmacology Deck 4 Flashcards
Of the following metals, which are not found naturally in humans?
Cu, Pb, As, Fe, Hg, Cd, Zn
Pb Hg, As, Cd
Give five signs of lead poisoning
Encephalopathy; constipation due to autonomic nerve damage; anemia; peripheral neuropathy; line in gingiva.
What drug developed at P&S is used to treat lead poisoning?
succimer (2,3-dimercaptosuccinic acid).
What three medications are used to treat mercury poisoning?
dimercaprol (BAL), DMPS, Succimer (last two can be administered orally and are best).
What is the drug of choice for treating Wilson’s disease?
penicillamine (copper chelating agent)
What chelating agent is used to treat arsenic, mercury and gold poisoning?
dimercaprol (aka BAL, British antiLewisite). Also used in mixed therapy for lead poisoning with CaNa2EDTA
What chelating agent is used to treat iron overload?
deferoxamine (Desferal) Can be used in patients suffering from thalessemia who receive repeated blood transfusions.
What is the difference in how H1 and H2 receptors cause vasodilation?
H1 - rapid and short vasodilation involving release of EDRF
H2 - causes dilation that develops more slowly and is more sustained.
What effect does histamine have on the heart?
In small amounts, no direct effect, increases HR via baroreceptor response to fall in BP.
In large amounts, increased sinus rate, rate of contraction, ventricular automaticity via calcium influx (H2 receptor effect). Also causes AV block (via H1 receptor effect) which can increase ventricular automaticity.
What effect does histamine have on lungs?
Causes bronchoconstriction via H1 receptors. Also increases secretion of airway fluid and electrolytes.
What effects does histamine have on GI?
histamine release from gastric mucosa stimulates secretion of acid from parietal cells via H2 receptors.
What effect does histamine have on CNS?
neurotransmitter in some regions of CNS. H1 receptors found in hypothalamus, increases wakefulness. May participate in regulation of drinking, body temp, BP control, perception of pain. Histamine stimulates peripheral nerve endings to cause pain and itching.
What is the difference between first generation and second generation antihistamines?
1st generation have sedating properties, while second generation do not.
What second generation (non sedating) antihistamines should we be aware of?
loratidine (claritin), fexofenadine (allegra), cetirizine (zyrtec)
What first generation (sedating) antihistamines should we be aware of?
chlorpheniramine (Chlor-Trimeton), cyclizine (Marezine), meclizine (Antivert), dimenhydrinate (Dramamine), diphenhydramine (Benadryl)
What effect on do antihistamines have on H1 and H2 receptors?
inhibit rapid vasodilation due to H1 receptors; residual slow vasodilator effect remains.
Why don’t second generation antihistamine cause sedation?
They do not cross blood brain barrier.
What drug has antiemetic effect and how does it work?
promethazine; blocks central muscarinic and dopamine receptors.
What antihistamines have anti-motion sickness effects and why?
Meclizine (Antivert), Cyclizine (Marezine) - marked effect; diphenhydramine (Benadryl) - moderate. First generation H1 antihistamines, cross BBB, also block muscarinic receptors similar to scapolomine effect.
What drugs inhibit basal acid secretion and by what mechanisms?
1) Cimetidine (Tagamet) - inhibits CYPs, H2 receptor blocker
2) ranitidine (Zantac) - H2 receptor blocker
3) Famotidine (Pepcid) - H2 receptor blocker
What effects to PGI2 have?
vasodilation; inhibition of gastric secretion; sensitization of nerve endings to painful stimulus
