Pyrethins - the effect on guinea pigs.

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daftscotslass

Post   » Fri Jul 28, 2006 11:59 am


Does anyone know about/have information on the effect of pyrethins on piggies? I've only heard bad things.

The largest chain of pet stores in the UK is stocking a line of insecticidal products for small animals which contain pyrethins as the active ingredient. I'm very concerned that it will be taken to be safe - many are now starting to recommend the products on various other forums.

I really don't know enough to comment about the effects on guinea pigs but would like to find out what I can to try and either get these products withdrawn or at least make them unpopular.

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Mum
I GAVE, dammit!

Post   » Fri Jul 28, 2006 12:01 pm


As I understand it they are toxic to guinea pigs.

The only safe products for guinea pigs are ivermectin, selamectin, and the ingredient in Advantage.

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daftscotslass

Post   » Fri Jul 28, 2006 12:04 pm


I'm just having a rummage just now to see if I can find any articles online and so far have one on fetotoxicity - i.e. high doses result in death of young in pregnant females.

I'm on a mission, now.

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Mum
I GAVE, dammit!

Post   » Fri Jul 28, 2006 12:06 pm


It's a good subject for discussion.

I'd like to know more also, since there are many products here with pyrethrins sold for small animals.

I found a very interesting article on pyrethrins and toxicity here
Last edited by Mum on Fri Jul 28, 2006 12:12 pm, edited 1 time in total.

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-JC-
I gave AGAIN, dammit!

Post   » Fri Jul 28, 2006 12:11 pm


I'd like to know too. I've googled it in the past, but not really got anywhere. All I know is that it must be an 'approved' substance, legally, or they wouldn't be able to sell it, but my own vet will not use it on guinea pigs. And almost everyone on GL concurs that it's bad for pigs.

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daftscotslass

Post   » Fri Jul 28, 2006 12:22 pm


There's really conflicting information regarding skin sensitivity with regards to pyrethins. This article - http://www.vpl.com/msds/adams_ftmist_msds.html - states that a specific pyrethin exhibited the potential to cause sensitisation in guinea pigs. As does this one - http://www.wmmg.com/pdf/msds/1600Xclude_MSDS_214-099_R3_WEB.pdf.

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LibraryGryffon

Post   » Fri Jul 28, 2006 12:27 pm


From the HSDB (Hazardous Substances Data Base)
PYRETHRIN I
CASRN: 121-21-1
For other data, click on the Table of Contents

Non-Human Toxicity Excerpts:

Natural pyrethrins are only moderately toxic to warm-blooded animals by oral admin but highly toxic by parenteral routes. ... differences between oral & parenteral toxicities are presumably a consequence of rapid metabolic detoxication. Thus rats can ingest over a 24-hr period a dose which is lethal if taken at one time, & can maintain this intake every day of their lives without apparent injury.
[Gosselin, R.E., R.P. Smith, H.C. Hodge. Clinical Toxicology of Commercial Products. 5th ed. Baltimore: Williams and Wilkins, 1984., p. III-352]**PEER REVIEWED**

When rats were fed pyrethrins at dietary level of 5000 ppm beginning 3 wk before ... mating, reproductive performance was not reduced, but weights of weanling were significantly lower than those of controls. When pyrethrins were fed at dietary level of 1000 or 5000 ppm for 2 yr, liver lesions included bile duct proliferation & focal necrosis of liver cells. Pyrethrins, esp synergized pyrethrins, produced enlargement, margination, & cytoplasmic inclusions in liver cells of rats.
[Hayes, Wayland J., Jr. Pesticides Studied in Man. Baltimore/London: Williams and Wilkins, 1982., p. 78]**PEER REVIEWED**

When pyrethrins were fed at a dietary level of 1000 or 5000 ppm for 2 yr, the liver lesions included bile duct proliferation & focal necrosis of the liver cells. /Pyrethrins/
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991., p. 592]**PEER REVIEWED**

Pyrethrins, especially synergized pyrethrins, produced enlargement, margination, & cytoplasmic inclusions in the liver cells of rats. At a dietary level of 1000 ppm pyrethrins & 10,000 ppm piperonyl butoxide, the changes were well developed in only 8 days but of course were not maximal. The changes were proportional to dosage & similar to those produced by DDT. The effects of the two materials were additive. /Pyrethrins/
[Hayes, W.J., Jr., E.R. Laws, Jr., (eds.). Handbook of Pesticide Toxicology. Volume 2. Classes of Pesticides. New York, NY: Academic Press, Inc., 1991., p. 592]**PEER REVIEWED**

In animals, large oral, inhaled, or topical doses of pyrethrins have produced CNS excitation, incoordination, tremors, seizures, and death. /Pyrethrins/
[McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2000.Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2000 (Plus Supplements)., p. 3204]**PEER REVIEWED**

Following absorption through the chitinous exoskeleton of arthropods, pyrethrins stimulate the nervous system, apparently by competitively interfering with cationic conductances in the lipid layer of nerve cells, thereby blocking nerve impulse transmissions. Paralysis and death follow. /Pyrethrins/
[McEvoy, G.K. (ed.). American Hospital Formulary Service - Drug Information 2000.Bethesda, MD: American Society of Health-System Pharmacists, Inc. 2000 (Plus Supplements)., p. 3203]**PEER REVIEWED**

Non-systemic insecticide with contact action. Causes paralysis initially, with death occurring later. Has some acaricidal activity. /Pyrethrins/
[Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994., p. 877]**PEER REVIEWED**
PYRETHRIN II
CASRN: 121-29-9
For other data, click on the Table of Contents


Non-Human Toxicity Values:

LD50 Rat male oral greater than 600 mg/kg [Hayes, Wayland J., Jr. Pesticides Studied in Man. Baltimore/London: Williams and Wilkins, 1982., p. 78]**PEER REVIEWED**

LD50 Mouse intraperitoneal less than 240 mg/kg [Hayes, Wayland J., Jr. Pesticides Studied in Man. Baltimore/London: Williams and Wilkins, 1982., p. 78]**PEER REVIEWED**

LD50 Cat female intravenous 1 mg/kg [Hayes, Wayland J., Jr. Pesticides Studied in Man. Baltimore/London: Williams and Wilkins, 1982., p. 78]**PEER REVIEWED**

LD50 Rat oral 1.2 g/kg [Budavari, S. (ed.). The Merck Index - Encyclopedia of Chemicals, Drugs and Biologicals. Rahway, NJ: Merck and Co., Inc., 1989., p. 1267]**PEER REVIEWED**

LD50 Rat (male) oral 2370 mg/kg /Pyrethrins/ [Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994., p. 878]**PEER REVIEWED**

LD50 Rat (female) oral 1030 mg/kg /Pyrethrins/ [Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994., p. 878]**PEER REVIEWED**

LC50 Rat inhalation 3.4 mg/l/4 hr /Pyrethrins/ [Tomlin, C.D.S. (ed.). The Pesticide Manual - World Compendium. 10th ed. Surrey, UK: The British Crop Protection Council, 1994., p. 878]**PEER REVIEWED**

LD50 Rat iv 1 mg/kg [Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996., p. 2830]**PEER REVIEWED**

And a regular PubMed search found this:
J Pharmacol Exp Ther. 2001 Sep;298(3):1067-82.

Actions of pyrethroid insecticides on sodium currents, action potentials, and contractile rhythm in isolated mammalian ventricular myocytes and perfusedhearts.

Spencer CI, Yuill KH, Borg JJ, Hancox JC, Kozlowski RZ.

Department of Pharmacology, School of Medical Sciences, University of Bristol,University Walk, Bristol, United Kingdom.

Pyrethroid insecticides are known to modify neuronal sodium channels, inducing persistent, steady-state sodium current at depolarized membrane potentials. Cardiac myocytes are also rich in sodium channels but comparatively little is known about the effect of pyrethroids on the heart, or on the cardiac sodium channel isoform. In the present study therefore, we determined the actions of type I and type II pyrethroids against rat and guinea pig ventricular myocytes under current and voltage clamp, and on isolated perfused rat hearts. In myocytes, tefluthrin (type I) and fenpropathrin and alpha-cypermethrin (type II) prolonged action potentials and evoked afterdepolarizations. The time course of sodium current (I(Na)) was also prolonged by these compounds. Pyrethroids delayed I(Na) inactivation, when measured under selective conditions as current sensitive to 30 microM tetrodotoxin, by increasing the proportion of slowly inactivating current at the expense of fast inactivating current. Further
experiments, focusing on fenpropathrin, revealed that its effects on I(Na) inactivation time course were dose-dependent, and the Na(+) "window-current" was increased in its presence. In unstimulated, isolated hearts perfused with the same pyrethroids, the variability in contraction amplitude increased due to variations in the intervals between heartbeats. These potentially arrhythmogenic changes are consistent with the effects observed at the cellular level. The type I pyrethroid tetramethrin had little effect in any of the preparations. These findings suggest that some pyrethroids possess considerable mammalian cardiac arrhythmogenic potential, the manifestation of which in vivo may depend on the route of exposure.
PMID: 11504804 [PubMed - indexed for MEDLINE]
And also this one:
J Toxicol Clin Toxicol. 2000;38(2):103-5.
Pyrethroid-induced paresthesia--a central or local toxic effect?

Wilks MF.
Medical Toxicology Unit, Guy's & St. Thomas' Hospital Trust, London, United Kingdom. Martin.Wilks@gstt.sthames.nhs.uk

BACKGROUND: Pyrethroid-induced paresthesia is frequently seen after dermal exposure to pyrethroids. Affected individuals experience a sensation of burning, tingling, itching, or numbness, most commonly in the face. This occurs 1-2 hours after the beginning of exposure and resolves spontaneously. MECHANISMS: Paresthesia occurs as a result of a direct effect on intracutaneous nerve endings at very low pyrethroid doses. It is related to potency of the pyrethroid with pyrethroids without an alpha-cyano group generally showing the weakest effect. CONCLUSION: Doses sufficient to cause paresthesia are far lower than those causing central or systemic toxicity. Paresthesia is therefore considered to be a localized nuisance effect. The best advice to affected individuals is to prevent paresthesia from occurring through appropriate hygiene measures and personal protection.
Publication Types: Review
PMID: 10778905 [PubMed - indexed for MEDLINE]
The bolds are mine. I'll keep looking, though I'm better at finding this info for people than animals. Just looking at this it would seem that Pyrethrin I is far less toxic than Pyrethrin II, and even that, the LD50s seem pretty high.

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Lynx
RESIST

Post   » Fri Jul 28, 2006 1:47 pm


LibraryGryffon, is this copyrighted or public info? I will have to delete it if it is copyrighted information.

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LibraryGryffon

Post   » Fri Jul 28, 2006 2:08 pm


Double post - see below
Last edited by LibraryGryffon on Fri Jul 28, 2006 2:11 pm, edited 1 time in total.

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LibraryGryffon

Post   » Fri Jul 28, 2006 2:09 pm


This should be public info since I got it the first two pieces off the NLM Toxnet page. The last two bits are abstracts and those are public, available at pubmed.gov
Last edited by LibraryGryffon on Fri Jul 28, 2006 2:17 pm, edited 1 time in total.

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Lynx
RESIST

Post   » Fri Jul 28, 2006 2:12 pm


Thanks! Just what I needed to know.

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LibraryGryffon

Post   » Fri Jul 28, 2006 2:24 pm


I should have mentioned that the HSDB was publicly available. Toxnet (http://toxnet.nlm.nih.gov/)is a great resource for chemical compound info. The HSDB entry for each compound has a section on both human and on animal toxicity.

Stuff through available through Toxnet and Pubmed (pubmed.gov will get you there) is public. In a sense we've already paid for it with our taxes since they're put out by the government.


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TWP_2

Post   » Fri Jul 28, 2006 2:53 pm


Sorry, the research to create those links took long enough that you all posted several times before I clicked submit.

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LibraryGryffon

Post   » Fri Jul 28, 2006 3:17 pm


That's more than OK. The link to the HSDB pages lets anyone interested easily find out the rest of the stuff they have including the human toxicity stuff too. And as I said, it's a really great resource.

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lisam

Post   » Fri Jul 28, 2006 3:17 pm


Pyrethrins are used quite a bit in horse fly sprays. I was confused, when reading directions, to discover that they give warnings not to get it on your skin when applying it. So why, if it's toxic to me, isn't it toxic to my horse?

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Lynx
RESIST

Post   » Fri Jul 28, 2006 3:30 pm


Ah, the .gov stuff! Love it! I have some NADA files on my site and there is copyright info saying we can use them. I used to just link to the files and they kept moving the darn things around so I had dead links! I just hated that. So I took them up on their being public documents and stuck them here.

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Perpetual Pig Slave

Post   » Sat Jul 29, 2006 12:41 am


I read an article in the Minneapolis paper last week that said companies are now installing "mosquito control systems" for your yard. They work similar to timed sprinkling systems except they spray pyrethins instead of water.

The article went on to say that pyrethins were safe for people but with widespread use there were some concerns with water quality and resistance in the mosquito population.

What are people thinking?? Where do they think the runoff goes. It not only kills the mosquitos but butterflies, moths, beetles, grubs, ants, spiders, and any other bug in your yard.. Wow look at the pretty DEAD zone.

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TWP_2

Post   » Sat Jul 29, 2006 2:49 am


I'd rather just build a cave in my backyard and breed bats.

They eat something like 3000 mosquitoes per night, and bats are way cuter than mosquitoes.

Jim

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Jennicat

Post   » Sat Jul 29, 2006 8:19 am


They say that pyrethrins are nonharmful to humans?

http://msds.ogden.disa.mil/msds/owa/web_msds.display?imsdsnr=9803

We used it as an insecticide in our greenhouses at school. It's certainly not safe to have on or in the air around you for an extended period of time, we had to wear respirators for it. It's not as dangerous as many chemicals, but I'd never spray it all over my yard daily though.

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