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Pharmacology Review

These are a few of the pearls gleaned from Thomas Pazdernik, PhD of pharmacology, author of a fantastic book:

Mosby’s Rapid Review:Pharmacology;

Pazdernik

This book is money in the bank. I have no monetary interest in promoting this book. Only my admiration for a truly student committed professor!

Dr. Paz not only outlines the majors and some of the minors needed for the USMLE, he highlights the must knows. I am somewhat biased, he did teach our course at the University of Kansas School of Medicine. However, our Pharmacology course consistently scored above the 90th percentile on the national shelf exams, so the praise is warranted. And if there is one course that pulled together the 1st two years of medical school, it is pharm. You must know Pharm to score well on the USMLE Step 1 and 2 (Esp. Step 1)


Now how do you go back and pull out all of this information? First thing you have to be able to do is put the drug in the right class. Usually if you can put the drug in the right class and you’ve learned the material reasonably well, it will come back to you fairly quickly. In some cases this is pretty easy because they have common endings. This is quite true for the second block. You have -quils and -olols and -sartans. But, as you saw in chemotherapy and in CNS, those drug names didn’t match so well within a given class.

Once you have identified where the drug belongs, you need to ask yourself, “what is the basic mechanism of the drugs within that class?” Usually that comes to you pretty easily. A lot of times, when you can put it in the right class you will know the mech. Then, don’t memorize all the pharmacokinetics, but memorize the UNIQUE pharmacokinetics. There are some drugs that can’t be given orally. Like Aminoglycosides. There are some drugs that rely primarily on renal mechanisms for elimination. So if you have renal dysfunction, you need to adjust the dose. There are other drugs that depend primarily on the liver.

We should know the difference between Neostigmine and Physostigmine. Neostigmine you would use if you wanted to treat Myasthenia Gravis. If you’re going to treat Atropine OD, then you need to use Physostigmine. Physostigmine crosses the Blood Brain Barrier.

What’s hit very hard on the boards is side effect profile. And many of the side effects you can figure out because they’re kind of an overextension of the pharmacological effect. So you should be understand, if you understand autonomic physiology, some of the side effects of some of the autonomic agents we’ve studied.

A lot of drugs have a signature side effect. It’s a side effect that’s kinda unique to that drug. This is particularly relevant in the anti-cancer drugs. Those are hit hard on board exams. You should know for example that Cyclophosphamide causes bladder cystitis. That Vincristine causes neurotoxicity. That Methotrexate causes Hepatotoxicity. That Cisplatin cause Nephro and Neurotoxicity. Duanorubicin and Doxirubicin causes Cardiac Toxicity. Bleomycin and Lung Toxicity. This is what I mean by signature side effects. These side effects are often kinda the rate limiting effect of the drug when it’s used clinically.

Then you should also have a good idea of some of the common uses of drugs. You don’t need to know all of the indications for a drug, but you should know how to treat Asthma. Know how to treat Arrhythmia and be able divide them into their classes.

Now what you uses to study for the boards and for your final depends a little bit by how you studied as you went through the course. Probably most of you are not going to have enough time to go back through all of your notes. If you made summary sheets or charts, you should use those.

Board Review books can also be very helpful at this point in time. There as helpful as how well you learned the material the first time you went through it. If you didn’t learn the material as you went through the course, then First Aid for the Boards is not going to be very meaningful to you at all.

I think maybe one of the best sources for the boards and maybe be more than what you can handle for the final, is the rapid review book that we’ve just came out with. It’s the Pharmacology Rapid Review Book by Mosely. This book is meant to be somewhere between what’s in First Aid and what’s in Baby Katzung. The strength of this is the disk in the back that has 500 questions that you can take in a tutorial mode or in an exam mode. If you take it in a Tutorial mode you can pull up the questions on Antibiotics. It will give you feedback as to whether it’s right or wrong. IF you take it in the exam mode it will give you 1 hour to do 50 questions. You can either do that within a subject area or a whole area of pharmacology. 100 of those questions are in here as a paper/pencil format. You can take it as an exam and go back and look at it.


One program on the web that is very high yield is under the General Principles Section. There’s a program that’s called MATCHING QUIZ. It kinda lists the hallmarks of some of the older classical drugs that are used to describe certain phenomena. Like Tetracycline causes discoloration of teeth. That Phenobarbital induces cytochrome P450. Phenoxybenzamine forms a covalent bond with the receptor.

On the board exams you’ll see a higher emphases on old classical drugs and prototypic drugs. It won’t necessarily look like the clinics are going to look. The drugs usually are chosen to illustrate a principle and if you’ve learned that principle, then it probably will be quite obvious why that drug is the right answer. So I think the matching thing is helpful.

Look at the clinical vignette-type questions presented in this course. We try to use questions that are very much like those that are on the board. A lot of those questions, you need to know 2 or 3 things to get them right. Q-bank from Kaplan is also very useful in preparing for the boards as well.

Look at table and figures when you look through your review books. Compare and contrast drugs. Many have done well on rote memorization from notes, but the boards will not be like that. You shouldn’t memorize verbiage, but you should understand the principles involved. A lot of the board questions are written so that most of the foils sound pretty good. If you really understand the basic principle, the right answer should be pretty obvious. Some situation that they’ve put the subject in may make one answer superior to the others.

Here’s an example:

Amiodarone has now become the recommended drug by ACLS for life threatening ventricular arrhythmias, but if you have a little clinical vignette with someone with severe COPD… then you’d go back to Lidocaine. The key here is that you have to recognize that Amiodarone has lung toxicity and should certainly be avoided.

You should have a good understanding of Absorbtion, Distribution, Metabolism and Excretion.


Some of the formulas that you might be seeing on the final or that you might be seeing on the boards… These are the ones you should probably know.

Vd = Amt. injected

--- ----------------

Amt. injected at time zero

Vd = Amt. IV

------------

C0

Kel = 0.7

-----

t ½

Cl = Kel x Vd

X = Css x Vd

Css = input = F x D/T

------ -----------

output Cl

IF you can work with these equations, you should be able to do any of the questions that you’ll be faced with.

Other important items you should know for boards:

  • The difference between a Zero order and First order reaction, and how you would graph that
  • Understand Half-life, 50% of the drug after one half life, 75% after two, 87% after three, etc.
  • There’s a fair amount of questions that deal with Signaling Pathways, maybe more coming of Biochemistry than from Pharmacology
  • You should know the kind of drugs that affect Gene Expression, like steroids for example. There’s multiple drugs (both endocrine and autonomic) that affect cAMP pathway. The PI pathway. You should know N.O. and EDRF. Also the various ionotropic mechanisms.
  • Dose-Response curves—you should know the basic terminology like what is an agonist, what is potency, what is affinity.
  • Understand graphically the difference between a full agonist and a partial agonist. Also an inverse agonist.
  • Understand the various way for graphing a competitive antagonist vs. a non-competitive antagonist. Understand the various ways you can plot this, like Lineweaver-Burke, etc.
  • Know the examples and definitions of Pharmacokinetic Tolerance, Pharmacodynamic Tolerance, the phenomena of Tachyphylaxis particularly with indirecting amines depleting the store of norepinephrine, Desensitization—usually due to a relatively rapid inactivation of a process (Ion channels can get trapped in an open or closed state—for example the nicotinic receptor), Down regulation—agonists down regulate receptor numbers per unit of tissue
  • You should know terms like Therapeutic Index, Margin of Safety,
  • You should know substances that are teratogenic
  • Fetal toxicity

You should understand the four types of Hypersensitivity Reactions For example:

  1. Clozapine - Agranulocytosis (type II)
  2. Serum Sickness - Type III
  3. Contact Sensitivity - type IV, like poison ivy

  • You should know and understand the abnormal responses that are influenced by Genetics
  • Inducers and Inhibitors of P450, know that Valproic Acid inhibits Cytochrome P450 (it’s the one that’s different from some of the other drugs used like Primidone, etc.)
  • ST. JOHN’S WART induces Cytochrome P450
  • Inhibitors—particularly Macrolide Antibiotics and Azole Antifungals!

Chemotherapy will be the hardest section. Spend some time with it.

Here is a sample of what to know:


Buzzwords for Chemotherapy

Drug that blocks excretion of penicillin and therefore can increase it’s half life

probenecid

Type of penicillin that has a half-life of more than 2 weeks and is considered a DEPOT form of penicillin

Benzathine Penicillin G

Which generation(s) of cephalosporins can enter the CNS

3rd and 4th

This cell wall synthesis inhibitor is inactivated by renal dipeptidase

Carbapenem (imipenem)

What is cilastatin used for

Cilastatin blocks the metabolism of imipenem by renal dipeptidase and can therefore increase it’s half-life

This cell wall synthesis inhibitor is associated with Red Man Syndrome

Vancomycin

Don’t give this protein synthesis inhibitor to children because it can concentrate in their teeth and growing bones

Tetracycline

This protein synthesis inhibitor is associated with Gray Baby Syndrome

Chloramphenicol – babys are poor glucoronidators L

This protein synthesis inhibitor is a potent inhibitor of CYP3A4 and went through FDA accelerated approval

Streptogramins

This protein synthesis inhibitor follows “Once daily dosing”

aminoglycosides

This folic acid inhibitor is also used in Ulcerative Colitis as a topical anti-inflammatory

Sulfasalazine

This DNA gyrase inhibitor has been associated with spontaneous rupture of Achilles tendon in animal rats

Fluoroquinolones

This urinary tract antiseptic works best in acidic urine

Nitrofurantoin

Name three systemic antibiotics that are used to treat UTI because they are efficiently cleared in the urine

Penicillin

Aminoglycoside

Sulfas


This 1st line antimycobacterial drug is associated with resistance from deleting katG gene

Isoniazid

(kat G gene is the gene that encodes a catalase that activates Isoniazid)

This 1st line antimycobacterial drug inhibits synthesis of arbinogalactan and is associated with visual disturbances(optic neuritis, low acuity, red-green problems) as it’s adverse effect

Ethambutol

This 1st line antimycobacterial drug is the only drug know to target RNA synthesis

Rifampin

This anti-parasitic drug is known to concentrate in the liver, spleen, and kidneys and is slowly released from those sites

Pentamidine

This alkylating agent is part of the MOPP regimen and is administered in arterial supply to the tumor

Mechlorethamine

This alkylating agent is associated with hemorrhagic cystitis which can be prevented with administration of mesna and adequate hydration

Cyclophosphamide

This alkylating agent is leukemogenic, teratogenic and is part of the MOPP regimen

Procarbazine

This anti-metabolite can be given in a high dose followed by “rescue with folinic acid (citrovorin, leucovorin)”

Methotrexate

Resistance to this group of anti-metabolite drugs is associated with a decrease in hprt activity

Purine Analogs:

6-Mercaptopurine

6-Thioguanine

These plant alkaloids are known as “spindle poisons” and stabilize microtubules so much so that they can’t be pulled apart

Taxol/Taxotere

(used predominantly in breast and ovarian cancer)


This anti-tumor antibiotic is associated with cardiotoxicity

Daunorubicin/Doxorubicin

This anti-tumor antibiotic is associated with pulmonary fibrosis

Bleomycin

This anti-tumor antibiotic has mechanism of action that is favored by hypoxia

Mitomycin – this is also the most toxic of all anti-tumor antibiotics

This anti-tumor antibiotic can be administered by bladder instillation

Mitomycin

GnRH antagonists are used to treat this type of cancer

Leuprolide is used to treat Prostrate cancer

Name the aromatase inhibitor that blocks the conversion of androgen to estrogen and is used in breast cancer unresponsive to tamoxifen

Triazole

Which tyrosine kinase inhibitor inhibits bcr-abl and is a great drug for CML

Gleevec

Estrogens are used to treat what type of cancer

Prostrate

Androgens are used to treat what type of cancer

Breast



CNS, and Autocoids, and Toxicity, should come back pretty easily.

DNA Viruses.... The Basics

Concepts:

  1. All DNA viruses, except, Parvoviruses are double-stranded (ds).
  2. All, except, Poxviruses duplicate their DNA in the nucleus.
    1. all, except, Pox -" in - a - Box" are icosahedral
  3. Naked DNA viruses are P.A.P. (You are naked to receive a "PAP")
    1. Parvo
    2. Adeno
    3. Papova
Replication:
  1. DNA viruses, except Hep B, duplicate their DNA by using it as a template to make DNA
    1. Hep B: Enveloped ds DNA virus that makes an RNA intermediate.
      1. All the other hepatitis viruses: All RNA virues, replicate thru RNA intermediates!
      2. A Polymerase, which is very similar to the retroviral reverse transcriptase, makes the new DNA from the RNA intermediate.
Parvovirus B19:
  • B19 is a naked ssDNA virus that causes fifth disease.
    • Fifth disease: (erythema infectiosum, a.k.a. slapped cheek fever)
      • infects adolescents, mild fever, and a recurring "slapped cheek" appearance with lacy rash on the arms and then body.
      • May cause Chronic anemia in immunocompromised pts.
      • aplastic crisis in sickle cell.
      • Can cause hydrops fetalis


PapOvaviruses: The "O" is for circular DNA. It is also Oooh, naked.
  • Two groups:
    • Papilloma (wart) viruses
    • Polyomaviruses
  • Human Papillomaviruses cause warts. They are transmitted by direct contact. Will cause a +PAP smear.
      • Notice how the higher the #, the worse it becomes.
    • Plantar warts are HPV 1 and 4: both benign
    • HPV 6 & 11 are the most common cause of anogenital warts (condylomata acuminata), which are sexually transmitted and laryngeal warts (usually seen in very young and sometimes aquired at birth).
    • Cervical intraepithelial carcinoma is most commonly assoc. w/ HPV 16 and 18.
      • The Early proteins of these oncogenic HPVs, E6 and #7, inactivate tumor suppressor fxns of p53 and p110-rb, respectively.
  • Polyomaviruses:
    • BK and JC are common but cause disease on in compromised pts.
      • BK - K is for kidney disease and often ends up w/ the patient needing a kidney transplant.
      • JC - assoc. w/ PML: progressive multifocal leukoencephalopathy.

ADENoviruses: Think of "a den" of coughing kids and adults w/ an ____ itis.
  • Pharygoconjunctivitis and keratoconjunctivitis: non purulent pink eye. inflammed and watery.
  • Acute respiratory diseases: most serious is interstitial pneumonitis in immunocompromised.
  • Adenoviruses 40 and 41 cause gastroenteritis.

HEPaDNAvirus: Hep B is an enveloped, partially ds DNA virus.
  • Transmission: The vowels are in the bowels for hepatitis, therefore, hep B is blood/parenterally or sex.
  • B/c, as you remember, it replicates thru an RNA intermediate, it carries in the mature virus particle (virion) a DNA polymerase with reverse transcriptase and DNA-dependent DNA polymerase activity.
    • DNA transcribed into RNA intermediate copied w/ reverse transcriptase into the new genomic partially stranded DNA
  • Disease is acute or chronic
    • Chronic: presence of HBsAg > 6mo.
    • On ave., pt is infectious for about 5 years and unable to suppress the production of HBsAg.

  • Diagnosis: made by serology, testing for the presence of IgM to HBcAg, anti-HBsAg, and HBsAg.
    • The presence of anti-HBeAg indicates a lower risk of transmission of the virus.


HERPESVIRUSES: Large family of enveloped, icosahedral, ds DNA viruses
  • Herpes simplex, varicella-zoster, cytomegalovirus, epstein-Barr,
  • Viruses of the herpes family are the ONLY ones whose envelope is from the host cell nuclear membrane modified by viral glycoproteins!
  1. HSVs. May cause acute or latent infections:
    1. Latent: HSV DNA is present in the nerve ganglia, and alpha (immediate early) proteins are expressed, but the beta viral proteins such as the HSV thymidine kinase and DNA polymerase (required for new DNA synthesis and for virus production).
      1. Thus, anti-HSV Rx like acyclovir (protease inh.), which inhibits DNA polymerase, do not wipe out latent infections!
      2. HSV - 1 usually above the waist - gingivostomatitis, keratoconjunctivitis and meningitis
      3. HSV - 2 usually below the waist - genital herpes and neonatal infections
  2. VZV. Primary infection: varicella or chickenpox.
    1. Children are considered contagious for 6 days after all lesions have dried
    2. VZV vaccine is an attenuated (live, but modified) strain of the virus.
    3. Secondary infetion: herpes zoster or shingles. Clusters of vesicular lesions, usually along a single sensory dermatome
    4. Immunocompromised: Tx is w/ varicella zoster immunoglobulin - VZIG and oral acyclovir
  3. CMV: extremely common
    1. Transmission: across placenta, aquired during birth or through mother's milk or direct contact w/ others, sexual contact or blood.
    2. Large cells w/ typical purple intranuclear inclusion bodies surrounded by a "halo" "owls eyes"!
    3. Disease: most are asymptomatic, but may be mononucleosis-like in adults.
      1. clinical dx - retinitis and interstitial pneumonitis in immunocompromised
        1. severe in immunocompromised
        2. cytomegalic inclusion disease - neonatal infection - hepatosplenomegaly w/ TTP, pneumonititis and CNS calcifications& microcephaly.
  1. EBV -
    1. Infects by binding CD-21 molocules on B lymphocytes
      1. 15-25yo. EB infectious mononucleosis
        1. SEVERE fatigue, pharyngitis/tonsillitis similar to strep, postcervical lymphadenopathy, hepatomegaly (elevated ALT) and splenomegaly.
        2. Downey type II cells
        3. Heterophile antibodies - unique to EBV infections - which react w/ animal red blood cell antigens (rather than the virus)
          1. Monospot
Poxviruses - pox - Pox in a box - very large and unusual ds DNA viruses, often described as having a brick-shaped complex appearance (pox-in-a-box)

    1. mAKE ALL NUCLEIC ACIDS IN THE CYTOPLASM. They require a virion-associated transcriptase.
    2. directs synthesis of its own envelope
    3. infection w/ pox produces cytoplasmic inclusion bodies.
      1. Variola: virus that caused smallpox. Extinct since 1977: You should never see the typical intracytoplasmic inclusion bodies, called Guarnieri bodies, since they have "guone" away.
      2. Vaccinia virus was the immunogen in the vaccine that led to the successful eradication of smallpos. Vaccinia is of uncertin origin.
      3. Mulluscum contagiosum: causes benign, pincushionlike, pink tumors w/ nipplelike indentations. Virus-infected cells have large eosinophilic cytoplasmic inclusion bodies called mulluscum bodies.
        1. severe in immunocompromised - of course!

RNA Viralology - Just the Basics, please!



Remember:  Viruses are 1) Energy-less.  They
float around until they come in contact with an appropriate cell   2) They are
basic life forms composed of protein coat, called a capsid that
surrounds genetic material.   3) The genetic material is either
DNA or RNA.  Never Both!!   4)
Replication of the genetic material occurs when the virus takes control of the
host cell's synthetic machine.

RNA (There are 3
types)
1. Positive (+) stranded
2. Negative (-) stranded
3.
Retroviruses
Viral Family
Envelope
RNA Structure
Capsid Symmetry
Medical Importance
Piconavirus
NO
SS + Linear
Icosahedral
"PERCH on a Peako"
Poliovirus - Salk/Savin - IPV/OPV
Echovirus - aseptic meningitis
Rhinovirus - "Common cold"
Coxsackievirus - aseptic meningitis, herpangina - febrile pharyngtis, hand/foot/mouth dx, myocarditis
Hav - acute viral hepatitis



Calicivaruses
NO
SS + Linear
Icosahedral
HEV
Norwalk - viral gastroenteritis, cruises
Reoviruses
No
DS linear, segmented
Icosahedral
Reovirus - colorado tick fever
Rotavirus - #1 cause of fatal diarrhea in children
R.O.T.A. - "Right Out The Anus"
Flavivirus
Yes
SS + Linear
Icosahedral
HCV
Yellow Fever
Dengue
St. Louis encephalitis
West Nile Virus
Togaviruses
Yes
SS + Linear
Icosahedral
Rubella (German measles) - descending rash
Eastern Equine encephalitis
Western Equine encephalitis
Retroviruses
Yes
SS + Linear
Icosahedral
Have Reverse transcriptase
HIV - AIDS
HTLV - T-cell leukemia
Coronaviruses
yes
SS + Linear
Helical
Coronavirus - "common cold" & SARS
Orthomyxoviruses
Yes
SS, -, linear segmented
helical
Influenenza
Orthomyxovirus - Ordinary flu
Paramyxoviruses
yes
SS, -, linear nonsegmented
helical
PaRaMyxovirus:
Parainfluenza - croup
RSV - bronciolitis in babies,
  • Rx-ribavarin
Measles
Mumps

PARAmyxovirus - PARAde of viruses
Rhabdoviruses
yes
SS -, linear
Helical
Rabies
Filoviruses
yes
SS - , linear
helical
Ebola/Marburg hemorrhagic fever,
  • often fatal
Arenaviruses
Yes
SS - , circular
helical
LCV - lymphocytic choriomeningitis
Menengitis - spread by mice
Bunyaviruses
yes
SS, -, circular
Helical
California encephalitis
Sandfly/Rift valley fevers
Crimean-Congo hemorrhagic fever
Hantavirus - hemorrhagic fever,
pneumonia
Deltavirus
Yes
SS, - , circular
Helical
HDV
Table adapted from FirstAid
USMLE Step 1

SS = single stranded
DS = double stranded
+ = positive polarity
- = negative polarity




1.  The POSITIVE (+) means that the RNA is
just like a messenger RNA (mRNA).  When a positive RNA virus enters a cell, its
RNA acts positively and immediately can be translated by the host's ribosomes
into protein. 

2.  Negative (-) stranded RNA viruses enter a cell, they are not able to begin translation immediately.  They must 1st get rid of their negative attitude and become POSITIVE (+) (like mRNA). 
  • To do this, Neg. viruses must carry , in their capsid, an enzyme called RNA-dependent RNA polymerase, which will carry out the transcription of the negative strand to positive strand. 
  • Human cells do not have RNA-dependent RNA polymerase!, so (-) viruses must carry their own negative attitude enzyme with them.

3.  One special RNA virus deserves mention here (RETROVIRUSES) The RNA of the retroviruses is transcribed in a reverse fashion into DNA.  So, to do this, they require Reverse Transcriptase.

For a different way to learn the viruses, check out the virus stories below.  Once you've drawn it out, written in your own notes and taught it to someone else, it IS yours!

To Good not to share...

This story is stolen from a friend.

A family was coming home from a long trip together. They had been vacationing and as usual the parents were tired and the two boys in the back were fighting. As they reached the outskirts of town, a truck crossed the median, careening straight into their path. As the father slammed on the break, this truck only picked up speed and smashed directly into them. Everyone was rushed to the hospital with the two boys taking the brunt of the accident. One of the boys was badly injured and in need of a transfusion to live. The boy was typed and crossed for blood type and was found to have a very rare blood type, of which the hospital was completely out of. The mother and father were asked if their blood could be tested and they said, of course, whatever it took. Their blood was drawn and it was found that their blood did not match. In tears, they came to the son who was least injured. He was older by two years, about 9 years old. His blood was found to be a perfect match. His father came to him in tears and said, "your brother is dying and needs blood. You see, he explained to his son, blood is what everyone needs to be alive. You can give your brother your blood and he will live". The older brother looked up at his father and said, "I will do it". As the nurses hooked up the lines and began to draw off the blood from from the older brother, a tear formed in his eye and he began to weep. His father came to him and said, "everything will be okay" and stroked his head. A deep resolution was seen in his eyes and the older brother looked over at his younger brother and said, "It will be okay, I love you". Then, he looked up at his father and said, "When will I die?"

As I think about this story, it reaches a deep core and exposes the weaknesses I see in myself. If knowing that I would die, would I have given the blood/sweat/time/resources

/money for my brother to live, like the one in the story? He did not know he would not die, yet was willing to give everything, so his brother could live. What have I sacrificed for someone? Have I left a legacy that entails the quote, "when I was born, I cried and people around me rejoiced. When I die, I want people to cry and for me to rejoice"!

Our time is short. Find a passion and live it fully with the expectation of a greater joy upon our death.

Virus Thoughts: 2009: H1N1

All the recent talk about a possible pandemic have caused quite a stir. It is yet to be determined whether this will be more serious but here is some info concerning the this virus. Food for thought (no pun intended)

Orthomyxovirus (Ordinary flu)
The new HA and NA antigens are given number subscripts to differntiate them. the pandemic of 1889 was caused by a virus with an H2 hemagglutinin, the pandemic of 1900 was caused by a new virus with H3 hemagglutinin; in 1918, a swine flu virus transferred its HA to a human virus and so was called Hswine hemagglutinin (HSW). The chart below is only included to demonstrate the many pandemics and their new HA and NA antigenic composition

Global Pandemics:
1889: H2N2
1900: H3N2
1918: H1N1 - "Spanish flu" - highly pathogenic stgrain - with high mortality
(est. 20-40 million deaths worldwide).
1947: H1N1*
1957: H2N2* "Asian Flu" - illness, but low mortality
1968: H3N2* "Hong Kong flu" - illness, but low mortality
1977: H1N1*
* Notice also tha.t some strains caused a second pandemic as a new unexposed population grows to adulthood
Will the next pandemic post be, 2009: H1N1 - swine flu?

Very important to remember!! Never give children with influenza or varicella (chicken pox) aspirin. Reye's Syndrome - Severe Liver and brain disease. It is not yet known why it occurs.

Check this site out!

http://www.twibes.com/group/USMLE-Prep