UMEM Educational Pearls - By Ellen Lemkin

Category: Toxicology

Title: Intermediate Syndrome

Keywords: organophosphates, intermediate syndrome (PubMed Search)

Posted: 9/6/2012 by Ellen Lemkin, MD, PharmD
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  • Exposure to organophosphates can lead to “intermediate syndrome.”
  • It is a syndrome characterized by weakness of neck flexors and proximal limbs, cranial nerve palsies, and respiratory muscle weakness, which can lead to respiratory paralysis.
  • It follows acute cholinergic syndrome and precedes a delayed neuropathy, thus it is an “intermediate syndrome,” typically developing 24-96 hours post exposure.
  • The pathophysiology of IMS remains unclear.
  • Serum cholinesterase levels and electrophysiological studies are helpful in confirming the diagnosis.
  • With supportive therapy, including artificial ventilation, complete recovery occurs within 5-18 days.

Category: Pharmacology & Therapeutics

Title: Drugs for UTIs

Keywords: Uti,bactrim,smx/tmp,ciprofloxacin,levofloxacin (PubMed Search)

Posted: 8/2/2012 by Ellen Lemkin, MD, PharmD
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Acute, uncomplicated cystitis (in the non-pregnant female):

·      The drug of choice is SMX/TMP (provided the resistance rate is <20%) X 3 days.

·      An alternative is nitrofurantoin X 5 days.

 

Acute, uncomplicated pyleonephritis (in the non-pregnanct female) may be treated with:

·      Levofloxacin X 5 days, or ciprofloxacin X 7 days (provided resistance rate is <10%).

·      Alternatively, SMX/TMP may be used X 14 days.

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No one treatment has demonstrated consistency of pain relief from jellyfish stings over all species; conversely, a treatment for one species may worsen an envenomation from another.

Deionized water, seawater, meat tenderizer, and urea treatment do not appear to produce any improvement in pain sensation.

Ammonia, acetic acid, and ethanol may cause an increased stinging sensation, and in most species vinegar may cause nematocyst discharge.

Application of topical lidocaine reduced the local sensation of pain (10% and 15% produced immediate pain relief), and hot water results in pain relief in the majority of patients tested.

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Category: Toxicology

Title: Vitamin K: not necessary for INR 4.5 to 10?

Keywords: Warfarin,vitamin K,coagulation,INR,supratherapeutic (PubMed Search)

Posted: 6/7/2012 by Ellen Lemkin, MD, PharmD
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It may not be necessary to give oral vitamin K to patients that are not bleeding that have INRs between 4.5 and 10.

Patients who were supratherapeutic on warfarin were randomized to vitamin K 1.25 mg (n=355) versus placebo (n=369).

In the 90 days after enrollment, 15.8% of patients allocated to vitamin K and 16.3% allocated to placebo had a bleeding event. Major bleeding events occurred in 9 patients in the vitamin K group and 4 in the placebo.

Thromboembolic events occurred in 1.1% of patients in the vitamin K group, compared to 0.8% of patients in the placebo group. An equal number of patients died in each group (n=7).

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Category: Pharmacology & Therapeutics

Title: Antibiotics For MRSA

Keywords: MRSA, antibiotic, pneumonia, VAP, cephalosporin, infection (PubMed Search)

Posted: 5/3/2012 by Ellen Lemkin, MD, PharmD
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If vancomycin resistance is suspected with MRSA infections, there are several other antibiotic choices. They are all extremely expensive.


Antibiotic ORAL Indication Precaution
Telavancin N

SSTI

May cause QT prolongation:

Caution with azole antifungals,

class III antiarrhythmics,

antidepressants, antipsychotics.

Interferes with coagulation tests.

Daptomycin N

SSTI

Bacteremia

Endocarditis

Not for pneumonia.

May cause rhabdomyolysis;

Discontinue statins.

Linezolid Y

VAP

SSTI

Not for bacteremia.

May cause serotonin syndrome;

Caution with antidepressants,

antipsychotics, tramadol, methadone.

Tigecycline N

 

Intrabdominal infections

SSTI

Not for bacteremia.

Inhibits clearance of warfarin.

Reserve for polymicrobial infections.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Skin and soft tissue infection (SSTI); ventilator acquired pneumonia (VAP)


Protamine for enoxaparin overdose

  • Protamine may be used to treat severe cases of hemorrhage in enoxaparin overdose
  • Protamine reverses the prolonged aPTT, but fails to completely reverse the anti-Xa effect (reverses about 60%)
  • Administer protamine by slow IV to equal the dose of enoxaparin injected: (1:1 ratio) 
  • if < 8 hours after last dose enoxaparin, give 1 mg protamine per 1 mg enoxaparin;
  • if 8-12 hours after last dose enoxaparin, give 0.5 mg protamine per 1 mg enoxaparin;
  • if >12 hours after last dose of enoxaparin,  protamine is not required

Category: Toxicology

Title: Octreotide for sulfonylurea overdose- updated

Keywords: Octreotide, sulfonylurea, glucose, insulin (PubMed Search)

Posted: 3/1/2012 by Ellen Lemkin, MD, PharmD
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  • Sulfonyurea overdose is associated with hypoglycemia, which may be delayed and prolonged.
  • Treatment with dextrose results in hyperglycemia, which potentiates insulin release from the pancreas, resulting in recurrent hypoglycemia.
  • Octreotide mimics somatostatin, which suppresses the secretion of glucagon and insulin, among others.
  • Octreotide binds with somatostatin receptors, closing calcium channels, preventing the influx of calcium and subsequent insulin release.
  • The dose is 100 mcg SUBCUTANEOUSLY, repeated every 8 hours as needed.

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Category: Pharmacology & Therapeutics

Title: Ondansetron: CONTRAINDICATIONS

Keywords: ondansetron, zofran, prolonged QT, torsades, drug interactions, ciprofloxacin, antifungal, azoles (PubMed Search)

Posted: 2/2/2012 by Ellen Lemkin, MD, PharmD
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There are many profound interactions with ondansetron that can potentially prolong the QT, leading to Torsades in susceptible patients
 
The highlights include:
  • Antifungal agents (the -azoles)
  • Class III antiarrhythmics
  • Fluoroquinolones
  • Low potency antipsychotic
 
It is actually CONTRAINDICATED in patients on ciprofloxacin
 
Use CAUTION in patients with electrolyte abnormalities, bradycardia, and CHF.
 
There are several other medication contraindications, including apomorphine, thioridazine, posaconazole, pimozide, sparfloxacin and cisapride.
 
http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm272041.htm#.TyrDf_YN5Wg.gmail

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Category: Pharmacology & Therapeutics

Title: Ceftaroline, a fifth generation cephalosporin

Keywords: MRSA, antibiotic, pneumonia, CAP, cephalosporin, infection (PubMed Search)

Posted: 1/5/2012 by Ellen Lemkin, MD, PharmD
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  • Approved for CAP and Skin/Skin structure infections
  • “Fifth generationcephalosporin- implies activity against MRSA, although has broad spectrum
  • Resistance is expected to be limited, with the exception of VRE, and VSE (vanco resistant or sensitive enterococcus faecalis)

  • Renally excreted

  • Common side effects: diarrhea, nausea, headache

  • Serious side effects: anaphylaxis, renal failure, hepatitis, seizure

  • Low incidence of C. difficile

  • Dose : 600 mg IV (over 1 hour) q12 hours X 5-7 days


Category: Toxicology

Title: High dose insulin in cardiogenic shock

Keywords: Insulin,beta blockers,calcium channel blockers (PubMed Search)

Posted: 12/1/2011 by Ellen Lemkin, MD, PharmD
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High dose insulin is recommended in treatment of beta-blocker and calcium channel blocker overdose. In a recent observational case series of cardiogenic shock, high dose insulin was evaluated for efficacy and safety.

 
The overdoses were primarily calcium channel and beta blockers, but included other agents
like tricyclic antidepressants.
  • Insulin doses were given at a maximum of 10 units/kg/hour.
  • Seven patients who were on vasopressors when enrolled were tapered off when placed on high dose insulin.
  • 11/12 patients lived and were discharged from the hospital.
  • Adverse effects included hypoglycemia (19 events) and hypokalemia (8).
Bottom line: High dose insulin, when used in doses up to 10 units/kg/hr allows avoidance of vasopressors, and appears to be effective in the treatment of toxin induced shock in this small case series.

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Category: Toxicology

Title: Salicylate Toxicity- Mechanism

Keywords: salicylate, aspirin, alkalosis, acidosis (PubMed Search)

Posted: 11/3/2011 by Ellen Lemkin, MD, PharmD (Updated: 10/21/2021)
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Salicylates:

  • stimulate the respiratory center in the brainstem, causing respiratory alkalosis
  • interfere with the Krebs cycle, limiting ATP production, leading to an anaerobic metabolism
  • uncouple oxidative phosphorylation, causing accumulation of pyruvic and lactic acid and heat production, resulting in acidosis and hyperthermia
  • increase fatty acid metabolism, generating ketone bodies

Overall, this results in a mixed respiratory alkalosis and metabolic acidosis. 

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Category: Pharmacology & Therapeutics

Title: The Nose Knows

Keywords: Intranasal administration,fentanyl,ketorolac,sumatriptin,glucagon,desmopressin,midazolam (PubMed Search)

Posted: 10/6/2011 by Ellen Lemkin, MD, PharmD
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There are an increasing number of intranasal medications commercially available for use, which is opportune as more and more intravenous medications become scarce.

These now include:

Generic name

Brand Name

Usage

Fentanyl

Instanyl

Opiate analgesic

Ketorolac

Sprix

NSAID analgesic

Desmopressin (DDAVP)

Stimate

Bleeding

Vitamin B12

Nasobal

Anti-migraine (yes!)

Sumatriptan

Imitrex

Anti-migraine

Zolmitripran

Zomig

Anti-migraine

*******In addition, you can administer glucagon, midazolam and narcan intranasally as well.

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Category: Pharmacology & Therapeutics

Title: Monitoring dabigatran

Keywords: thrombin,dabigatran,partial thromboplastin,bleeding (PubMed Search)

Posted: 9/1/2011 by Ellen Lemkin, MD, PharmD (Updated: 10/21/2021)
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Dabigatran is an oral thrombin inhibitor approved for the prevention of thromboembolism in patients with atrial fibrillation and for those undergoing orthopedic surgery.
 
In normal situations, it is not necessary to monitor any laboratory values. However, in the potential overdose situation or in the event of bleeding, it would be useful to assess the anticoagulant status. 
  • The thrombin clotting time (TT) directly assesses the activity of direct thrombin inhibitors (like dabigatran), and displayes a linear dose-response curve over therapeutic concentrations. At high levels, the test frequently exceeds the maximum measurements.
  • The PT and INR are less sensitive and cannot be recommended.
  • The activated partial thromboplastin time can provide qualitative assessment of anticoagulant activity but is not sensitive at supratherapeutic doses. 
 
Bottom Line:
In emergency situations, the aPTT and TT are the most effective qualitative methods widely available for determining the presence or absence of anticoagulant effect in patients receiving dabigatran.

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Category: Toxicology

Title: acetaminophen

Keywords: acetaminophen,pain (PubMed Search)

Posted: 8/4/2011 by Ellen Lemkin, MD, PharmD
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o   The FDA is now asking manufacturers to limit the amount of acetaminophen in combination products to 325 mg per dose.

o   The higher dose formulations will be phased out by 2014.

o   The FDA is also considering lowering the maximum total to 3 gm per day, and a maximum dose of 650 mg per dose

o   This does not pertain to OTC, but this is likely to change in the near future; Johnson & Johnson (manufacturer of Tylenol) has already adopted these recommendations.

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Category: Toxicology

Title: Caffeine and Cardiac Arrhythmias

Keywords: caffeine, arrhythmias, cardiac (PubMed Search)

Posted: 7/7/2011 by Ellen Lemkin, MD, PharmD (Updated: 10/21/2021)
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Caffeine and Cardiac Arrhythmias

Many physicians will tell patients to avoid caffeine as it is thought to lead to arrhythmias, however evidence does not support this practice.
  • Animal studies show high doses of caffeine produces catecholamine triggered activity

  • Small studies in high risk patients (recent MI, malignant arrhythmias) have shown no increase in frequency or severity of arrhythmia

  • No large scale human studies exist evaluating caffeine's effects on patients with malignant arrhythmias (VF/VT)

  • Overall, the data suggest that caffeine is well tolerated in moderate doses in most patients, even those with known or suspected arrhythmias

  • In patients who claim sensitivity to caffeine, or in those with known arrhythmias where catecholamines are felt to drive the arrhythmia, caffeine may be discouraged by physicians.

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Category: Pharmacology & Therapeutics

Title: IV acetaminophen

Keywords: acetaminophen,pain,narcotic,Ofirmev,intravenous (PubMed Search)

Posted: 5/5/2011 by Ellen Lemkin, MD, PharmD
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IV acetaminophen has been approved for use since November 2010

It is indicated for the:

  • Treatment of mild to moderate pain
  • Combination therapy with opioids for treatment of moderate to severe pain
  • Fever reduction

The results of studies demonstrating opoid sparing effects have been mixed; some studies have not demonstrated either a reduction in opioid dose or opioid side effects.

The dose is the same for acetaminophen administered by other routes.

It must be administered over 15 minutes, and onset of activity is 15 minutes. Peak effect occurs at one hour.

The MAJOR drawback is the cost, which is $13 dollars per vial. This is compared to oral acetaminophen and ibuprofen, which are pennies.

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Category: Toxicology

Title: Radiation and potassium iodide

Keywords: radiation, iodide, KI, thyroid, iodine-131 (PubMed Search)

Posted: 4/7/2011 by Ellen Lemkin, MD, PharmD
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·      In the event a nuclear power plant accident, people may be exposed to a mixture of radioactive products. The main radionuclides representing health risk are radioactive caesium and radioactive iodine.

·      Iodine-131 is concentrated in the thyroid gland and may eventually lead to development of thyroid nodules and thyroid cancer.

·      Radioiodine uptake by the thyroid can be blocked by taking potassium iodide (KI) pills or solution, preventing these effects.

·      KI should not be taken in the absence of a clear risk of exposure to a potentially dangerous level of radioactive iodine because KI can cause allergic reactions, skin rashes, salivary gland inflammation, hyperthyroidism or hypothyroidism.

·      Since radioactive iodine decays rapidly, current estimates indicate there will not be a hazardous level of reaching the United States from this accident.

·      There are three FDA approved KI products: Iosat, Thyrosafe and ThyroShield.

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Category: Toxicology

Title: Spider bite

Keywords: Brown Recluse,envenomation,spider,loxoscelism (PubMed Search)

Posted: 3/3/2011 by Ellen Lemkin, MD, PharmD
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Recently a case report was published in which a child was incorrectly diagnosed with MRSA. He actually had systemic loxoscelism from a Brown Recluse spider bite.

A patient who has been bitten by brown recluse spider bite may present with pruritis, pain and swelling. The classic lesion has a bluish-purple central region, surrounded by concentric rings of pale ischemia and erythema. (“red, white and blue”) Bites may progress over days to a bleb with necrosis and eschar formation, followed by ulceration.

Systemic loxoscelism presents with a scarlatiniform rash that spreads dependently. It may have the classic purple lesion surrounded by concentric rings of pale ischemia and erythema. The patient may be uncomfortable but is usually stable. Treatment is supportive care.

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Category: Toxicology

Title: Methemoglobinemia

Keywords: Methemoglobinemia,methylene blue (PubMed Search)

Posted: 2/3/2011 by Ellen Lemkin, MD, PharmD (Updated: 10/21/2021)
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Suspect methemoglobinemia if you have a patient with persistent cyanosis, tachypnea, low pulse oximetry, and a lack of response to 100% oxygen therapy, or an elevated PaO2 on ABG and a low O2 sat on pulse ox.
 
Methemoglobin results from exposure to chemicals that oxidize the ferrous iron in hemoglobin to the ferric state, resulting in a functional anemia.  Usually a low level is reduced back to hemoglobin by cytochrome b5, NAD, G6PD, and glutathione reduction enzyme systems.  
 
Diagnose by confirmed by a methemoglobin level, although the most convenient and rapid test of choice is multiple wave co-oximetry. (not the standard 2 wave pulse ox).
 
Treat if they are symptomatic; use methylene blue, 1 mg/kg slow push. Patients should improve in one hour. Use with extreme caution in patients with G6PD disease (if at all).
 

Category: Toxicology

Title: Intravenous vitamin K1

Keywords: Vitamin K1,anaphylaxis,coumadin,warfarin (PubMed Search)

Posted: 1/6/2011 by Ellen Lemkin, MD, PharmD (Updated: 10/21/2021)
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  • Vitamin K can be used intravenously for management of the NON bleeding patient with a high INR (>9).
  • Although anaphylactoid reactions have been described, most cases occurred with large doses of vitamin K, administered rapidly, and with little dilution.
  • It is estimated that the incidence of anaphylaxis is 3:10,000 doses.
  • The subcutaneous route of administration is not recommended because of its delayed and unpredictable responses.

 

 

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