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.
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