Wednesday, June 12, 2013

Main Psychiatry Drug Uses


  • Bupropion - Smoking cessation
  • Buspirone - Generalized anxiety disorder
  • Clozapine - Schizophrenia ( positive and negative symptoms)
  • Cyproheptate - Serotonin syndrome
  • Dantrolene - Neuroleptic malignant syndrome
  • Disulfiram - Alcoholism
  • Duloxetine - Diabetic peripheral neuropathy
  • Haloperidol - Schizophrenia (positive symptoms)
  • Imipramine - Bedwetting
  • Lithium - Bipolar disorder
  • Methadone - Heroin detoxification
  • Metylphenidate - ADHD
  • Mirtazapine - Depression with insomnia
  • Phenelzine - Hypochondriasis
  • Sertraline - Bulimia
  • Thiamine - Wernicke-Korsakoff synfrome
  • Trazodone - Insomnia

Wednesday, April 4, 2012

Hyperkalemia

  1. Digoxin vs Spironolactone
    • Hyperkalemia + confusion, nauseas, vomiting, and anorexia = Digoxin

Friday, March 30, 2012

Gout vs Pseudogout

  1. Crystals:
    • Gout = NEGATIVELY birefringent (uric acid)
    • Pseudogout = POSITIVELY birefringent (calcium pyrophosphate)
  2. Treatment:
    • Gout:
      • Acute attack: 1st line NSAID's except aspirin; 2nd line COLCHICINE
      • Chronic: URICOSURICO agents (Never use in acute crisis)

Number needed to harm (NNH)


NNH represents the number of people that need to be treated for one adverse event to ocurr.
  1. Formula: NNH = 1 / ARI
    • NNT: number needed to harm
    • ARI: absolute risk increase
    • ARI = AR: atributabe risk
  2. Classic USMLE Question:
      • "You are asked to analyze survival data after six months of treatment with a drug X. The results are given below:
                                                 Alive                Dead
        Treated +                             10                  15
        Treated -                              10                  30

        What is the number needed to harm for drug X?
      • Answer
        NNH = 1 / AR
                 = 1 / (a / a+b) - (c / c+d)

        a / a + b = treatment group = 10 / (10 + 15) = 0.40
        c / c + d = placebo group = 10 / (10 + 30) = 0.25

        NNH = 1 / (0.40 - 0.25) = 1 / 0.15 = 66.6 or 67 

Bias

  • Selection bias, nonrandom assignment to study group, or subjects are allocated in a group without regard their individual characteristics than influenced in the results.
    • The more ill subjects are in one group, the less ill subjects in the other.
  • Recall bias, knowledge of presence of disorder. (see video) 
    • To know to have a disease and don't want to answer questions.
    • To have a children with a congenital disease and recall previous risk factors.
  • Sampling bias, subjects are not representative relative to general population.
  • Late-look bias, information gathered at an inappropriate time.
    • Using a survey to study a fatal disease in a patient who is alive. 
  • Procedure bias, subjects in control and study group does not receive the same treatment.
  • Confounding bias, the effect of one risk factor distorts the effect of the other.
    • Smokes distorts the cholesterol effect (alone) in acute myocardial infarcts.
  • Lead-times bias, early detection of a disease, before it appeared by its natural history. 
    • HIV detection before it become AIDS, treatment changes disease's natural history. 
  • Pygmalion effect, researcher's belief in the efficacy of a treatment changes the outcome of the treatment.
  • Hawthorne effect, group being studied changes its behavior to meet the expectations of the researcher.
    • Patients answer yes to every risk factor to give a positive disease.
  • Detection bias, more information is attempted to obtain from a exposed group than the control group.
  • Allocation bias, subjects are not assigned to study in a non-random fashion.