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Topic: TOAD TOXINS

0.0  OVERVIEW
 0.1  LIFE SUPPORT
        This overview assumes that basic life support measures
        have been instituted.
 0.2  CLINICAL EFFECTS
  0.2.1  SUMMARY
    A.  There are several types of toxic substances found in
        toads, including cardioactive agents, catecholamines,
        indolealkylamines and non-cardiac sterols.  These toxins
        are located in the skin and parotid glands and may be
        transferred by handling or ingesting a toad's skin.
  0.2.3  HEENT
    A.  Secretions of the toad parotid glands will cause pain
        and severe irritation when placed in eyes, nose, and
        throat.
  0.2.4  CARDIOVASCULAR
    A.  Dogs who have been poisoned with bufagins develop
        ventricular fibrillation and symptoms resembling
        digitalis poisoning.  Vasoconstriction may also be seen.
  0.2.5  RESPIRATORY
    A.  Dyspnea and weakened respirations may be seen.
  0.2.6  NEUROLOGIC
    A.  Paralysis and seizures have been reported in both humans
        and animals.  Many bufagins have local anesthetic
        actions, especially on the oral mucosa.
  0.2.7  GASTROINTESTINAL
    A.  Salivation and vomiting were often seen in animals.
        These toxins may cause numbness of the oral mucosa if
        ingested.
  0.2.14  HEMATOLOGIC
    A.  Cyanosis has been seen in poisoned dogs.
  0.2.18  PSYCHIATRIC
    A.  HALLUCINATIONS:  Drug users have been known to smoke the
        chopped skins of toads for their hallucinogenic effect.
 0.3  LABORATORY
   A.   No toxic levels have yet been established for any of the
        bufagins.  Since many of the other substances are
        metabolized rapidly, laboratory analysis is impractical.
 0.4  TREATMENT OVERVIEW
  0.4.1  SUMMARY
    A.  There are three primary areas of toxicity, the first
        involving cardiac glycoside effects, the second, the
        pressor effects, and the third, the hallucinogenic
        effects.  Usually the cardiovascular effects are the
        most prominent.  Treatment is directed at prevention of
        absorption, and monitoring for EKG effects and
        hyperkalemia.  Lidocaine, a transvenous pacemaker, and
        cholestyramine have all been used to treat digitalis-
        like poisonings.  FAB fragments have not been reported
        to be of use in toad poisoning.
    B.  Hemodialysis has been ineffective in removing cardiac
        glycosides.
 0.5  RANGE OF TOXICITY
   A.   The skin of one toad is sufficient to cause significant
        symptoms and even death in both animals and humans.
Topic: TOAD TOXINS

   B.   No toxic serum or blood levels have yet been established.
1.0  SUBSTANCES INCLUDED
 1.1  THERAPEUTIC/TOXIC CLASS
   A.   There are several types of toxic substances found in the
        venom of toads.
    1.  CARDIOACTIVE SUBSTANCES:  Bufagins (bufandienolides) are
        cardioactive substances found in toad venom.  They have
        effects similar to the cardiac glycosides found in
        plants.  Bufotoxins are the conjugation products of the
        specific bufagin with one molecule of suberylargine
        (Chen & Kovarikova, 1967).  Bufotoxins were originally
        isolated from the parotoid glands of toads, but have
        since been seen in various plants and mushrooms
        (Siperstein et al, 1957; Lincoff & Mitchel, 1977; Kibmer
        & Wichtl, 1986).
    2.  CATECHOLAMINES:  There are also several catecholamines
        in toad venom.  Epinephrine has been found in as high a
        concentration as 5% in the venom of several species.
        Norepinephrine has also been found (Chen & Kovarikova,
        1967).
    3.  INDOLEALKYLAMINES:  Chemicals found include several
        bufotenines.  Bufotenines are organic bases containing
        an indole ring and have primarily oxytocic actions and
        often pressor actions (Palumbo et al, 1975).  Specific
        substances include bufothionine, serotonin,
        cinobufotenine, bufotenine, and dehydrobufotenine (Chen
        & Kovarikova, 1967).  Bufotenine is the 5-hydroxy
        derivative of N,N,dimethyltryptamine and is a
        hallucinogen (Gilman et al, 1985).
    4.  NONCARDIAC STEROLS:  The sterols found in toad venom
        include cholesterol, provitamin D, gamma sitosteral, and
        ergosterol.  They do not appear to have a significant
        role in toxicity (Chen & Kovarikova, 1967; Palumbo et
        al, 1975).
 1.3  DESCRIPTION
   A.   Toads known to contain toxins include:
        1.  Bufo alvarius
        2.  Bufo americanus
        3.  Bufo arenarum
        4.  Bufo asper
        5.  Bufo blombergi
        6.  Bufo bufo
        7.  Bufo bufo gargarizans
        8.  Bufo formosus
        9.  Bufo fowerii
        10. Bufo marinus
        11. Bufo melanostictus
        12. Bufo peltocephalus
        13. Bufo quercicus
        14. Bufo regularis
        15. Bufo valliceps
        16. Bufo viridis
 1.4  GEOGRAPHICAL LOCATION
   A.   Toads are found throughout the world, Bufo marinus having
        one of the widest distributions.
Topic: TOAD TOXINS

2.0  CLINICAL EFFECTS
 2.1  SUMMARY
   A.   Poisoning by toad toxins is primarily a problem with
        animals and may be fatal (Perry & Bracegirdle, 1973).
        There have been fatalities in Hawaii, Phillipines, and
        Fiji occurring after eating the toads as food (Tyler,
        1976; Palumbo et al, 1975).  The toxins are located in
        the skin and parotid glands and may be transferred by
        handling a toad.  A toad that sits in a dog's watering
        dish for some time may leave enough toxin to make the pet
        ill (Smith, 1982).  The toxicity varies considerably by
        the toad species and its geographic location.  The death
        rate for untreated animals exposed to Bufo marinus is
        nearly 100% in Florida, is low in Texas, and only about
        5% in Hawaii (Palumbo et al, 1975).
 2.3  HEENT
  2.3.2  EYES
    A.  IRRITATION:  If the secretions of the toad parotid
        glands come in contact with human eyes, pain and severe
        irritation will result (Tyler, 1976; Smith, 1982).
  2.3.4  NOSE
    A.  IRRITATION:  Exposure of the nasal mucous membranes to
        the toad toxins may produce severe irritation (Chen &
        Kovarikova, 1967).
  2.3.5  THROAT
    A.  The mouth and throat may become anesthetized if
        bufotoxins have been ingested (Chen & Kovarikova, 1967).
 2.4  CARDIOVASCULAR
   A.   VENTRICULAR FIBRILLATION:  Dogs intentionally poisoned
        with bufagins orally develop ventricular fibrillation and
        if untreated - death (Palumbo et al, 1975).  The symptoms
        resemble digitalis poisoning.
   B.   VASOCONSTRICTION:  Bufagins constrict arterial blood
        vessels (Chen & Kovarikova, 1967).  Bufotenine itself is
        not hallucinogenic, but acts as a pressor rather than a
        hallucinogen in humans (Kantoretal, 1980).
 2.5  RESPIRATORY
   A.   DYSPNEA:  Weakened respirations may be seen if toad
        toxins have been ingested (Smith, 1982).
 2.6  NEUROLOGIC
   A.   PARALYSIS:  Paraplegia has been noted in toad poisonings
        of dogs and cats.  Incoordination and progressive
        paralysis may be earlier symptoms (Perry & Bracegirdle,
        1973; Smith, 1982).
   B.   SEIZURES:  Have been reported in poisoned dogs and a few
        cats (Palumbo et al, 1975; Chen & Kovarikova, 1967), as
        well as a 5-year-old boy (Hitt & Ettinger, 1986).  Onset
        was within 5 minutes.  The seizures continued unabated
        for 60 minutes.
   C.   LOCAL ANESTHESIA:  Many bufagins have local anesthetic
        actions, especially on the oral mucosa (Chen &
        Kovarikova, 1967).
 2.7  GASTROINTESTINAL
   A.   SALIVATION:  Intense salivation is usually seen in
        poisoned cats and dogs (Perry & Bracegirdle, 1973), and
Topic: TOAD TOXINS

        was seen in one 5-year-old boy (Hitt & Ettinger, 1986).
   B.   VOMITING:  Is often present in animals (Perry &
        Bracegirdle, 1973).
   C.   NUMBNESS:  If ingested, the toxins cause numbness of the
        oral mucosa (Smith, 1982; Chen & Kovarikova, 1967).
 2.12  FLUID-ELECTROLYTE
   A.   HYPERKALEMIA:  Similar to that seen with digitalis
        poisoning, may be seen.
 2.13  TEMPERATURE REGULATION
   A.   FEVER:  Is a symptom common to ingestion of toads by cats
        and dogs (Perry & Bracegirdle, 1973).
 2.14  HEMATOLOGIC
   A.   CYANOSIS:  Has been seen in dogs (Hitt & Ettinger, 1986).
 2.15  DERMATOLOGIC
   A.   PERSPIRATION:  Although handling toads is generally not
        considered seriously injurious to humans, it is thought
        to dramatically reduce perspiration (Smith, 1982).
 2.18  PSYCHIATRIC
   A.   HALLUCINATIONS:  In 1971, drug users in Queensland were
        smoking the chopped skins of Bufo marinus for its
        hallucinogenic effect (Tyler 1976).  Toad skin has been
        used for its hallucinogenic properties throughout the
        world (Emboden, 1979), but Bufo alvarins is the only Bufo
        species known to contain a hallucinogenic tryptamine
        (McKenna & Towers, 1984).
3.0  LABORATORY
 3.2  MONITORING PARAMETERS/LEVELS
  3.2.1  SERUM/BLOOD
    A.  No toxic levels have yet been established for any of the
        bufagins.  Many of the other substances are metabolized
        rapidly, and laboratory analysis would be impractical.
  3.2.3  OTHER
    A.  EKG:  Patients who have had significant exposures should
        have a baseline EKG to observe for abnormalities.
        Symptomatic patients should continue to have EKGs
        performed.
    B.  A serum potassium level should be drawn to test for
        hyperkalemia (Chen & Kovarikova, 1967).
4.0  CASE REPORTS
   A.   A typical animal case report involves a dog that finds a
        slow hopping toad and mouths the animal playfully.  The
        animal usually experiences immediate salivation, and
        irritation of the mucus membranes of the mouth and
        throat.  If the dog eats the toad, vomiting and paralysis
        may lead to seizures and death.  Animals who recover
        usually do not have significant sequelae.
   B.   Although human deaths have been reported in the lay
        literature, we were able to find only one case report of
        a human death or serious intoxication in the medical
        literature.  This was a 5-year-old who had mouthed a Bufo
        alvarius (Colorado River Toad) and developed status
        epilepticus successfully treated with diazepam and
        phenobarbital (Hitt & Ettinger, 1986).
5.0  TREATMENT
 5.1  LIFE SUPPORT
Topic: TOAD TOXINS

      Support respiratory and cardiovascular function.
 5.2  SUMMARY
   A.   There are 3 primary areas of toxicity.  The first
        involves the cardiac glycoside-like effects of the
        bufagins; the second is the pressor effects of the
        catecholamines; and the third is the hallucinogenic
        effect of the indolealkylamines.  After a toad had been
        ingested, it is difficult to evaluate which of these
        effects will predominate.  Usually, the cardiovascular
        effects are the most prominent.  The patient should be
        observed for arrhythmias and for hallucinations.  There
        have been minimal human exposures, so clinical
        presentation and course are difficult to predict.
 5.3  ORAL/PARENTERAL EXPOSURE
  5.3.1  PREVENTION OF ABSORPTION
    A.  EMESIS
    1.  Emesis may be indicated in substantial recent
        ingestions unless the patient is obtunded, comatose or
        convulsing or is at risk of doing so based on
        ingestant.  Emesis is most effective if initiated
        within 30 minutes of ingestion.  Dose of ipecac syrup:
        ADULT OR CHILD OVER 90 TO 100 POUNDS (40 to 45
        kilograms):  30 milliliters; CHILD 1 TO 12 YEARS:  15
        milliliters; CHILD 6 TO 12 MONTHS (consider
        administration in a health care facility): 5 to 10
        milliliters.  After the dose is given, encourage clear
        fluids, 6 to 8 ounces in adults and 4 to 6 ounces in a
        child.  The dose may be repeated once if emesis does
        not occur within 30 minutes.
    2.  If emesis is unsuccessful following 2 doses of ipecac,
        the decision to lavage or otherwise attempt to
        decontaminate the gut should be made on an individual
        basis.  This amount of ipecac poses little toxicity of
        itself.
    3.  Refer to the IPECAC/TREATMENT management for further
        information on administration and adverse reactions.
    B.  MULTIPLE DOSE ACTIVATED CHARCOAL/CATHARTIC
    1.  Cardiac glycosides and bufandienolides are adsorbed to
        activated charcoal and enterohepatic circulation may be
        decreased by multiple-dose activated charcoal (Balz &
        Bader, 1974).
    2.  Repeated oral charcoal dose (every 2 to 6 hours) may
        enhance total body clearance and elimination.  A saline
        cathartic or sorbitol may be given with the first
        charcoal dose and repeated until charcoal appears in
        the stools.  Do not repeat charcoal if bowel sounds
        absent.
    3.  Administer charcoal as slurry.  The FDA suggests a
        minimum of 240 milliliters of diluent per 30 grams
        charcoal (Dose: Optimum dose of charcoal is not
        established; usual INITIAL dose is 30 to 100 grams in
        adults and 15 to 30 grams in children; some suggest
        using 1 to 2 grams per kilogram as a rough guideline,
        particularly in infants).  REPEAT doses have ranged
        from 20 to 50 grams in adults.  Doses in children have
Topic: TOAD TOXINS

        not been established, but one-half the initial dose is
        recommended.
    4.  Administer a saline cathartic or sorbitol, with the
        INITIAL charcoal dose, mixed with charcoal or
        administered separately.  Dose:
        a.  Magnesium or sodium sulfate (ADULT:  20 to 30 grams
            per dose; CHILD: 250 milligrams per kilogram per
            dose) OR magnesium citrate (ADULT AND CHILD:  4
            milliliters per kilogram per dose up to 300
            milliliters per dose).
        b.  Sorbitol (ADULT: 1 to 2 grams per kilogram per dose
            to a maximum of 150 grams per dose; CHILD: (over 1
            year of age):  1 to 1.5 grams per kilogram per dose
            as a 35 percent solution to a maximum of 50 grams
            per dose).  Consider administration in a health care
            facility, monitoring fluid-electrolyte status,
            especially in children.
    5.  When used with multiple-dose charcoal regimens, the
        safety of repeated cathartics has not been established.
        Hypermagnesemia has been reported after repeated
        administration of magnesium containing cathartics in
        overdose patients with normal renal function.  In young
        children, cathartics should be repeated no more than 1
        to 2 times per day.  Administration of cathartics
        should be stopped when a charcoal stool appears.
        Cathartics should be used with extreme caution in
        patients who have an ileus or absent bowel sounds.
        Saline cathartics should be used with caution in
        patients with impaired renal function.
    6.  Refer to the ACTIVATED CHARCOAL/TREATMENT management
        for further information on administration and adverse
        reactions.
    C.  One of the best first aid measures to prevent toxicity
        in animals is to immediately flush the oral mucous
        membranes of dogs, cats, and even people who have had
        mucous membrane exposure to decrease absorption.  Do not
        swallow the rinse water.
  5.3.2  TREATMENT
    A.  CARDIAC EFFECTS
    1.  MONITOR EKG CONTINUOUSLY:  For abnormal cardiac rates
        and rhythms.  In patients with previously healthy
        hearts, the most common manifestation is bradycardia
        with or without varying degrees of AV block.  Peaked T
        waves, depressed ST segments, widened QRS, and
        prolonged PR interval may also be noted.
    2.  HYPERKALEMIA:  Hyperkalemia following acute overdose
        may be life-threatening.  The emergency management of
        life-threatening hyperkalemia (potassium levels greater
        than 6.5 mEq/L) includes the intravenous administration
        of bicarbonate, glucose, and insulin.  DOSE:
        Administer 0.2 units/kg of regular insulin with 200 to
        400 mg/kg glucose (IV dextrose 25% in water).
        Concurrent administration of IV sodium bicarbonate
        (approximately 1.0 mEq/kg up to 44 mEq per dose in an
        adult) may be of additive value in rapidly lowering
Topic: TOAD TOXINS

        serum potassium levels.  Monitor the EKG while
        administering the glucose, insulin, and sodium
        bicarbonate.  This therapy should lower the serum
        potassium level for up to 12 hours.
    3.  ATROPINE:  Atropine is useful in the management of
        bradycardia, varying degrees of heart block and other
        cardiac irregularities due to the digitalis-like
        induced effects of enhanced vagal tone on the SA node
        rhythmicity and on conduction through the AV node.
        DOSE:  Adult:  0.6 mg per dose IV; Child:  10 to 30
        mcg/kg per dose up to 0.4 mg per dose (may be repeated
        as needed to achieve desired effects).  Monitor EKG
        carefully while administering atropine.
    4.  PHENYTOIN:  Phenytoin is useful in the management of
        digitalis-like induced ventricular dysrhythmias and
        improves conduction through the AV node.  Low dose
        phenytoin (Adult:  25 mg per dose IV at 1 to 2 hour
        intervals; Child:  0.5 to 1.0 mg/kg per dose IV at 1 to
        2 hour intervals) appears to improve AV conduction.
        Larger doses are needed for the management of
        ventricular dysrhythmias:  Loading Dose for adults and
        children:  Administer 15 mg/kg up to 1.0 gram IV not to
        exceed a rate of 0.5 mg/kg per minute.  Maintenance
        Dose:  Adults - administer 2 mg/kg IV every 12 hours as
        needed; Child - administer 2 mg/kg every 8 hours as
        needed.  Monitor serum phenytoin levels just prior to
        initiating and during maintenance therapy to assure
        therapeutic levels of 10 to 20 mcg/ml (39.64 to 79.28
        nmol/L).  Monitor EKG carefully.
    5.  LIDOCAINE
      a.  Lidocaine is useful in the management of ventricular
          tachyarrhythmias, PVC's, and bigeminy.  Lidocaine does
          not improve conduction through the AV node.
      b.  ADULT:  BOLUS: 50 to 100 milligrams (0.70 to 1.4
          milligrams per kilogram) under EKG monitoring.  Rate:
          25 to 50 milligrams per minute (0.35 to 0.70
          milligrams per kilogram per minute).  A second bolus
          may be injected in 5 minutes if desired response is
          not obtained.  No more than 200 to 300 milligrams
          should be administered during a one hour period.
          INFUSION: Following a bolus, an infusion at 1 to 4
          milligrams per minute (0.014 to 0.057 milligram per
          kilogram per minute) may be used.  PEDIATRIC:  BOLUS:
          1 milligram per kilogram.  INFUSION:  3 micrograms per
          kilogram per minute.
    6.  TRANSVENOUS PACEMAKER:  Insertion of a transvenous
        pacemaker should be considered in those patients with
        severe bradycardia and/or slow ventricular rate due to
        second degree AV block who fail to respond to atropine
        and/or phenytoin drug therapy.
    7.  FAB FRAGMENTS:  Have not been documented to be of any
        value in the treatment of bufagins.  Cross reactivity
        has not been proven.
    8.  CHOLESTYRAMINE:  Digitoxin (and theoretically bufagins)
        elimination appears to be enhanced by the serial
Topic: TOAD TOXINS

        administration of cholestyramine, 4 grams orally every
        6 hours.  Cholestyramine appears to have minimal effect
        on absorption and excretion of cardiac glycosides in
        man.
    9.  One 5-year-old boy did well on high-dose hydrocortisone
        sodium succinate and phenobarbital (Hitt & Ettinger,
        1986).
    B.  ANIMALS (ESPECIALLY DOGS) (Palumbo et al, 1975):
    1.  ATROPINE:  May be used to decrease secretions and block
        vagal effects.  It is not a specific antidote.
    2.  ANTIHISTAMINES OR CORTICOSTEROIDS:  May reduce the
        effects of bufotoxins on the mucous membranes of the
        mouth and other organs, but have little direct action.
    3.  PENTOBARBITAL-INDUCED ANESTHESIA:  Does increase canine
        tolerance to toad venom intoxication.
    4.  PROPRANOLOL:  Has been tried on canines, with some
        success.  The dose used was high:  5 mg/kg.
  5.3.3  ENHANCED ELIMINATION
    A.  MULTIPLE DOSE ACTIVATED CHARCOAL:  May be of some use.
        It has been used after IV administration of methyl
        proscillaridin (Belz & Bader, 1974).
    B.  HEMODIALYSIS:  Has been ineffective in removing cardiac
        glycosides but may assist in restoring potassium to
        normal levels.  It has yet to be tried on bufagins.
 5.6  DERMAL EXPOSURE
  5.6.1  DECONTAMINATION
    A.  Wash exposed area extremely thoroughly with soap and
        water.  A physician may need to examine the area if
        irritation or pain persists after washing.
  5.6.2  TREATMENT
    A.  Effects may be seen after dermal exposure.  Treatment
        should be as appropriate under the oral treatment
        section.
6.0  RANGE OF TOXICITY
 6.2  MINIMUM LETHAL EXPOSURE
   A.   The skin of one toad is sufficient to cause significant
        symptoms and even death in both animals and humans.
 6.4  TOXIC SERUM/BLOOD CONCENTRATIONS
   A.   No toxic serum or blood levels have yet been established.
 6.6  LD50/LC50
   A.   TABLE I - BUFAGIN LETHAL DOSES IN CATS
                NAME                    Mean (Geo.)
                                        LD,, mg/kg
        Arenobufagin                    0.08
        Bufotalin                       0.13
        Desacetylbufotalin              0.26
        Cinobufagin                     0.20
        Acetylcinobufagin               0.59
        Desacetylcinobufagin            inactive
        Cinobufotalin                   0.20
        Acetylcinobufotalin             0.18
        Desactylcinobufotalin           inactive
        Marinobufagin                   1.49
        Acetylmarinobufagin             0.95
        12Beta-Hydroxymarinobufagin     3.00
Topic: TOAD TOXINS

        Bufotalidin (hellebrigenin)     0.08
        Acetylbufotalidin               0.06
        Resibufogenin                   inactive
        Acetylresibufogenin             inactive
        12Beta-Hydroxyresibufogenin     4.16
        Bufalin                         0.14
        Telocinobufagin                 0.10
        Bufotalinin                     0.62
        Artebufogenin                   inactive
        Gamabufotalin                   0.10
        Vallicepobufagin                0.20
        Quercicobufagin                 0.10
        Viridobufagin                   0.11
        Regularobufagin                 0.15
        Fowlerobufagin                  0.22
   B.   TABLE II BUFOTOXIN LETHAL DOSES IN CATS
                NAME                    Mean (Geo.)
                                        LD, mg/kg
        Viridobufotoxin                 0.27
        Vulgarobufotoxin                0.29
        Cinobufotoxin                   0.36
        Gamabufotoxin                   0.37
        Arenobufotoxin                  0.41
        Marinobufotoxin                 0.42
        Regularobufotoxin               0.48
        Alvarobufotoxin                 0.76
        Fowlerobufotoxin                0.79
   C.   REFERENCE:  (Chen & Kovarikova, 1967).
 6.8  OTHER
   A.   The structure of the cardioactive bufadienolides leads to
        greater potency than the corresponding plant glycosides
        thus the cardenolides of plants - digitoxigenin,
        periplogenin, oleandrigenin, sarmentogenin, and
        strophanthidin, corresponding to bufalin,
        telocinobufagin, bufotalin, gamabufotalin, and
        bufotalidin - have lower toxicities.
   B.   The toxicity of the cardioactive bufotoxins is lower than
        those of the corresponding bufagins (bufadienolides)
        (Chen & Kovarikova, 1967).
   C.   The skin of Bufo alvarius contains 5-methoxy-N,N-
        dimethyltryptamine (5-MeO-DMT) at a concentration of 50
        to 160 mg/g of skin (Daly & Witkop, 1971).
7.0  AVAILABLE FORMS/SOURCES
   A.   BUFOTOXINS:  Is the name of a collection of compounds
        found in the toad venom which may be secreted into toad
        skin or found in 2 glands behind the eyes, called parotid
        glands (Tyler, 1976).  Bufotoxins may also be
        specificially applied to the conjugates of a bufagin with
        suberylargine.
   B.   Before digitalis was extracted from Digitalis purpura,
        dried and powdered toad skins were used as a cardiac
        medication (Burton, 1977).  Other "folk" uses include
        expectorant, diuretic, and remedy for toothaches,
        sinusitis, and hemorrhage of the gums.
   C.   Toad skins have also been used for their hallucinogenic
Topic: TOAD TOXINS

        effect (Emboden, 1979).
8.0  KINETICS
 8.1  ABSORPTION
   A.   The oral absorption of the bufagins and bufotoxins is
        generally poor.  Less than 15% of cinobufagin is absorbed
        orally in rats.
   B.   Other components of toad venom are rapidly absorbed via
        mucous membranes and cause immediate symptoms in animals
        (Smith, 1982).
 8.4  EXCRETION
  8.4.3  BILE
    A.  Little could be found concerning the excretion of these
        compounds; similar cardenolides and substances such as
        proscillaridin are excreted largely in the bile (Belz &
        Bader, 1974).
9.0  PHARMACOLOGY/TOXICOLOGY
 9.1  PHARMACOLOGIC MECHANISM
   A.   Most bufandienolides are cardiotonic sterols synthesized
        by toads from cholesterol (Siperstein, 1957).  The
        lactone ring is 6-membered of an alpha pyrone type
        attached to C17.  They have a secondary hydroxy group at
        C3 and are called bufagins - which corresponds to the
        aglycones found in the cardiac glycosides in plants.
        None of these bufandienolides conjugates with a
        carbohydrate (as do the plants) to form glycosides, but
        some do form bufotoxins by combining with suberylargine
        (Chen & Kovarikova, 1967).
   B.   In the toad, some of these compounds (eg, resibufogenin)
        are ouabain-like and increase the force of contraction of
        heart muscle (Lichtstein et al, 1986).
   C.   The pharmacology of the catecholamines found in toad
        venom is well known and need not be discussed here.
   D.   INDOLEALKYLAMINES:  Pharmacology is also known.  Besides
        having some hallucinogenic effects, these compounds may
        stimulate uterine and intestinal muscle (Chen &
        Kovarikova, 1961).
 9.2  TOXICOLOGIC MECHANISM
   A.   Bufagins and bufotoxins have been shown to inhibit
        sodium, potassium, ATPase activity (Lichtstein et al,
        1986).  Their action is almost the same as that of the
        digitalis glycosides (Palumbo et al, 1975).
12.0  REFERENCES
 12.1  GENERAL REFERENCES
 1.  Belz GG & Bader H:  Effect of oral charcoal on plasma
     levels of intravenous methyl proscillaridin.  Klin
     Wochenschr 1974; 52:1134-1135.
 2.  Burton R:  Venomous Animals:  Colour Library International
     Ltd.  London, 1977.
 3.  Chen KK & Kovarikova A:  Pharmacology and toxicology of
     toad venom.  J Pharm Sci 1967; 56:1535-1541.
 4.  Daly JW & Witkop B:  Chemistry and pharmacology of frog
     venoms.  In:  Bucherl W & Buckly EE (eds).  Venomous
     Animals and Their Venoms, vol 2, Academic Press, New York,
     1971.
 5.  Emboden W:  Narcotic Plants.  MacMillan Publishing Company,
Topic: TOAD TOXINS

     Inc, 1979.
 6.  Gilman AG, Goodman LS, Rall TW et al:  The Pharmacological
     Basis of Therapeutics, 7th ed.  MacMillan Publishing
     Company, 1985.
 7.  Gould L, Solomon F, Cherbakoff A et al:  Clinical studies
     on proscillaridin, a new squill glycoside.  J Clin
     Pharmacol 1971; 11:135-145.
 8.  Hitt M & Ettinger DD:  Toad toxicity.  N Engl J Med 1986;
     314:1517.
 9.  Kantor RE, Dudlettes SD & Shulgin AT:  5-Methoxy-a-methyl-
     tryptamine (a, O-dimethylserotonin), a hallucinogenic
     homolog of serotonin.  Biological Psychiatry 1980;
     15:349-352.
 10.  Kibmer B & Wichtl M:  Bufadienolide aus samen von
      helleborus odorus.  Planta Med 1986; 2:77-162.
 11.  Lichtstein P, Kachalsky S & Deutsch J:  Identification of
      a ouabain-like compound in toad skin and plasma as a
      bufodienolide derivative.  Life Sci 1986; 38:1261-1270.
 12.  Lincoff G & Mitchel DH:  Toxic and Hallucinogenic Mushroom
      Poisoning.  Van Nostrand Reinhold Company, Dallas, 1977.
 13.  McKenna DJ & Towers GH:  Biochemistry and pharmacology of
      tryptamines and beta-carbolines, a minireview.  J
      Psychoactive Drugs 1984; 16:347-358.
 14.  Palumbo NE, Perri S & Read G:  Experimental induction and
      treatment of toad poisoning in the dog.  J Am Vet Med
      Assoc 1975; 167:1000-1005.
 15.  Perry BD & Bracegirdle JR:  Toad poisoning in small
      animals.  Vet Rec 1973; 92:589-590.
 16.  Siperstein MD, Murray AW & Titus E:  Biosynthesis of
      cardiotonic sterols from cholesterol in the toad Bufo
      marinus.  Arch Biochem Biophys 1957; 67:154-160.
 17.  Smith RL:  Venomous Animals of Arizona.  Cooperative
      Extension Service, College of Agriculture, Univ AZ,
      Tucson, 1982.
 18.  Tyler MJ:  Frogs.  William Collins Ltd, Sydney, 1976.
13.0  AUTHOR INFORMATION
   A.   Written by:  David G. Spoerke, M.S., RPh., 06/86
   B.   Reviewed by:  Ken Kulig, M.D., 06/86
   C.   Specialty Board:  Biologicals
   D.   In addition to standard revisions of this management
        certain portions were updated with recent literature:
        11/86.