ECTONOR LIQUID

Indications

• Control of agricultural pests
• Public health pest control
• Vector control for diseases transmitted by insects

Dosage

Children: Refer to specific guidelines based on the formulation and target pest, as dosages can vary widely. Consult the product label or BNF for precise dosing information.

Adults: Refer to specific guidelines based on the formulation and target pest, as dosages can vary widely. Consult the product label or BNF for precise dosing information.

Mechanism of action

Cypermethrin exerts its effects primarily at voltage-sensitive sodium channels in both insect and mammalian neurons. It enhances the binding of specific ligands to these channels, leading to prolonged depolarization of the neuron and disruption of normal nerve function. Additionally, cypermethrin may also act on the gamma-aminobutyric acid (GABA) receptor-chloride ionophore complex, further contributing to its neurotoxic effects.

Pharmacodynamics

As a pyrethroid, cypermethrin has a high affinity for sodium channels, which causes sustained activation and subsequent paralysis of the insect’s nervous system. This mechanism results in the inability of the insect to coordinate movement or respond to stimuli, ultimately leading to death. The insecticidal potency is influenced by the stereochemistry of the compound, with different isomers demonstrating varying levels of effectiveness.

Pharmacokinetics

Cypermethrin is absorbed through the exoskeleton of insects and can also be absorbed through the skin in mammals. Once in the system, it is metabolized in the liver, with metabolites excreted primarily in urine. The compound has a relatively low bioavailability in mammals and is rapidly eliminated. Environmental factors such as temperature and moisture can influence its degradation and persistence in the environment.

Adverse effects

• Skin irritation
• Respiratory issues
• Nausea
• Headache
• Dizziness

Precautions

• Use with caution in patients with known hypersensitivity to pyrethroids
• Avoid contact with eyes and mucous membranes
• Use personal protective equipment when handling

Pregnancy

Cypermethrin should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is not known whether cypermethrin is excreted in human milk; caution should be exercised when administering to breastfeeding women.

Storage

Store in a cool, dry place, away from direct sunlight and heat. Keep out of reach of children.

Formulations

• Liquid concentrate
• Aerosol spray
• Emulsifiable concentrate

Indications

• Scabies
• Head lice
• Crab lice

Dosage

Children: For children, apply once weekly for 2 doses, applying preparation over the whole body including face, neck, scalp, and ears, and wash off after 8–12 hours.

Adults: Apply once weekly for 2 doses, applying 5% preparation over the whole body including the face, neck, scalp, and ears, and wash off after 8–12 hours.

Mechanism of action

Permethrin acts on the nerve cell membrane to disrupt the sodium channel current that regulates membrane polarization. This leads to delayed repolarization and paralysis of the pests. It is pediculocidal by interfering with sodium channel currents in the louse's nerve cell membranes, resulting in paralysis and death of the insect.

Pharmacodynamics

As a pyrethroid, permethrin is effective against a wide range of arthropods including lice, ticks, fleas, and mites. Its neurotoxic effects are due to its ability to prolong sodium channel activation, resulting in sustained depolarization of nerve membranes and subsequent paralysis of the parasites.

Pharmacokinetics

Permethrin is minimally absorbed through the skin, which limits systemic exposure. Its pharmacokinetics are influenced by the formulation used, but it is primarily localized to the application site. Metabolism occurs mainly in the liver, and it is eliminated through fecal and urinary routes.

Contra-indications

• Hypersensitivity to permethrin or any of its excipients
• Children under 6 months (for certain formulations without medical supervision)
• Broken or secondarily infected skin

Adverse effects

• Scalp irritation
• Skin reactions
• Burning sensation
• Contact dermatitis
• Allergic reactions

Precautions

• Avoid contact with eyes
• Avoid contact with mucous membranes
• Medical supervision required for children under 2 years
• Caution in patients with severe eczema or asthma

Pregnancy

Permethrin should be used during pregnancy only if clearly needed and if the benefits outweigh the risks.

Breast-feeding

Permethrin is generally considered safe during breastfeeding, but caution should be exercised.

Storage

Store in a cool, dry place, away from direct sunlight.

Formulations

• 5% cream
• Cutaneous spray solution
• Lotion
• Other topical formulations

Mechanism of action

Pyrethroid insecticides are synthetic neurotoxins patterned after the naturally occurring pyrethrins. Their mechanism of action is thought to involve effects primarily at the voltage-sensitive sodium channel of both insect & mammalian neurons, although recent studies have raised the possibility that these cmpds may also act at the gamma-aminobutyric acid receptor-chloride ionophore complex. Here we show that active pyrethroids of the alpha-cyano-3-phenoxybenzyl class allosterically enhance the binding of (3)H-batrachotoxinin-A 20-alpha-benzoate to voltage-sensitive sodium channels of rat brain in a dose-dependent & stereospecific manner. Comparison of the rank order of potency for enhancement of (3)H-batrachotoxinin-A 20-alpha-benzoate binding & insecticidal activity in a series of toxic steroisomers of cypermethrin, representative of the class, reveals a correlation between the two measures. These results support a sodium channel site model for pyrethroid action & suggest a useful & practical method to help evaluate the relationship between the sodium channel & insecticidal potency for members of this class of cmpds. 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/ The efforts of this study were directed at defining the importance of esterases, mixed function oxidases and mitochondrial respiratory chain enzymes in in vitro covalent binding of cismethrin and the two cyanopyrethroids, cypermethrin and deltamethrin to phenobarbital induced rat liver homogenate and microsomes. Each enzyme system was selectively inhibited to elucidate the activation mechanism involved. Piperonyl-butoxide and carbon-monoxide were used to inhibit mixed function oxidases. Tetraethylpyrophosphate inhibited esterase and trichloropropene-oxide inhibited epoxide-hydrolase. Potassium cyanide or rotenone was used to block the mitochondrial electron transport. The study demonstrated that covalent binding of cismethrin, cypermethrin, and deltamethrin was dependent on pyrethroid concentration. Inhibition of esterases and mitochondrial respiration only slightly altered the covalent binding level. Inhibition of cytochrome p450 and mixed function oxidases reduced the covalent binding, making it almost nonexistent. The covalent binding was decreased by 50% through an 80% inhibition of epoxide-hydrolase. In vitro, the comparison of data between alcohol and acid labeling of the same pyrethroid suggested that the whole molecule was bound to proteins in an activation process, perhaps epoxidation, and that hydrolysis could only occur afterwards. The role of cytochrome p450 dependent monooxygenases in the covalent binding process was stressed. Interaction with sodium channels is not the only mechanism of action proposed for the pyrethroids. Their effects on the CNS have led various workers to suggest actions via antagonism of gamma-aminobutyric acid (GABA)-mediated inhibition, modulation of nicotinic cholinergic transmission, enhancement of noradrenaline release, or actions on calcium ions. Since neurotransmitter specific pharmacological agents offer only poor or partial protection against poisoning, it is unlikely that one of these effects represents the primary mechanism of action of the pyrethroids, & most neurotransmitter release is secondary to incr sodium entry. /Pyrethroids/ For more Mechanism of Action (Complete) data for CYPERMETHRIN (12 total), please visit the HSDB record page.

Mechanism of action

Permethrin acts on the nerve cell membrane to disrupt the sodium channel current by which the polarization of the membrane is regulated. Delayed repolarization and paralysis of the pests are the consequences of this disturbance. Permethrin is pediculocidal by disrupting in sodium channel current in the louse's nerve cell membrane; this action causes delayed polarization of the membrane and paralysis of the insect. Like natural pyrethrins, permethrin acts as a neurotoxin by depolarizing nerve cell membranes of parasites. The drug disrupts the sodium channel current by which membrane repolarization is regulated. Delayed repolarization results in paralysis of the nerves in the exoskeletal respiratory muscles of the parasite leading to death. The synthetic pyrethroids delay closure of the sodium channel, resulting in a sodium tail current that is characterized by a slow influx of sodium during the end of depolarization. Apparently the pyrethroid molecule holds the activation gate in the open position. Pyrethroids with an alpha-cyano group (e.g., fenvalerate) produce more prolonged sodium tail currents than do other pyrethroids (e.g., permethrin, bioresmethrin). The former group of pyrethroids causes more cutaneous sensations than the latter. /Synthetic pyrethroids/ Trans- and cis-permethrin were irradiated in sunlight and at gamma>290 nm in hexane, methanol, water and water acetone. Isomerization and ester cleavage occurred primarily. Observed products included monochloropermethrin and the monochlorovinyl acid from cleavage, 3-phenoxybenzyl 3,3-dimethylacrylate, 3-phenoxybenzaldehyde, 3-phenoxybenzoic acid, benzyl alcohol, benzaldehyde, 3-hydroxybenzyl alcohol, benzoic acid, 3-hydroxybenzoic acid, and 3-phenoxybenzyl alcohol. For more Mechanism of Action (Complete) data for PERMETHRIN (10 total), please visit the HSDB record page.

Pharmacodynamics

Permethrin, a pyrethroid, is active against a broad range of pests including lice, ticks, fleas, mites, and other arthropods.