Nexgard spectra

Indications

• Flea infestations in dogs
• Tick infestations in dogs
• Control of parasitic infections caused by ectoparasites

Dosage

Children: Refer to the BNF for Children for specific dosing guidelines.

Adults: The typical dose for dogs is 2.5 mg/kg body weight, administered orally once a month.

Mechanism of action

Afoxolaner acts by selectively inhibiting the glutamate-gated chloride channels (GluCl) and gamma-aminobutyric acid (GABA) receptors in the nervous system of insects and arachnids. This inhibition leads to hyperexcitation of the nervous system, resulting in paralysis and death of the parasites.

Pharmacodynamics

Afoxolaner is effective against various species of fleas and ticks. Its potency is primarily due to its selective binding to the specific receptors in the parasites' nervous system, which are not present in mammals, thus reducing the risk of toxicity to the host. The compound exhibits a favorable safety margin in dogs, and its pharmacodynamic profile allows for effective control of parasitic infestations.

Pharmacokinetics

Afoxolaner is well absorbed after oral administration, with peak plasma concentrations occurring within 4 to 8 hours. It has a high volume of distribution and is extensively metabolized in the liver. The elimination half-life is approximately 2 weeks, allowing for sustained efficacy against parasites. Afoxolaner is primarily excreted through feces and urine, with a minor fraction remaining unchanged.

Adverse effects

• Vomiting
• Diarrhea
• Anorexia
• Lethargy
• Ataxia

Precautions

• Use with caution in animals with a history of seizures.
• Monitor for any signs of adverse reactions, especially in sensitive populations.

Pregnancy

Safety in pregnant animals has not been established. Use only if the benefits outweigh the risks.

Breast-feeding

Safety in lactating animals has not been established. Use only if the benefits outweigh the risks.

Storage

Store at room temperature, away from moisture and direct sunlight.

Formulations

• Oral chewable tablets
• Topical solution

Indications

• Treatment of intestinal nematodes
• Control of ectoparasites such as mites and fleas

Dosage

Children: Refer to the BNF for Children for appropriate dosing information for pediatric patients.

Adults: Refer to the BNF for specific dosing guidelines as they may vary based on the condition being treated.

Mechanism of action

Milbemycin acts on the nervous system of parasites by enhancing the effects of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). This action leads to increased neuronal inhibition, resulting in paralysis and death of the parasites.

Pharmacodynamics

Milbemycin is effective against a range of parasites due to its selective action on GABA receptors in invertebrates. By potentiating GABA-mediated neurotransmission, milbemycin causes flaccid paralysis in susceptible organisms, which is essential for its antiparasitic efficacy.

Pharmacokinetics

Information regarding the pharmacokinetics of milbemycin, including absorption, distribution, metabolism, and excretion, is limited. However, it is known to be well-absorbed after oral administration and may have a prolonged half-life, allowing for sustained antiparasitic action.

Pregnancy

The safety of milbemycin during pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Caution should be exercised when administering milbemycin to breastfeeding mothers. The effects on nursing infants are not well studied.

Storage

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

Formulations

• {'formulation': 'Oral tablet', 'strength': 'Varies'}
• {'formulation': 'Topical solution', 'strength': 'Varies'}

Indications

• Organophosphate poisoning
• Acetylcholinesterase inhibitor toxicity
• Cholinergic crisis

Dosage

Children: Refer to specific guidelines or protocols for pediatric dosing based on the particular oxime used and the severity of poisoning.

Adults: Refer to specific guidelines or protocols for dosing based on the particular oxime used and the severity of poisoning.

Mechanism of action

Oximes work by reactivating acetylcholinesterase, an enzyme that hydrolyzes the neurotransmitter acetylcholine. In cases of organophosphate poisoning, these compounds bind to the phosphorylated active site of the inhibited enzyme and facilitate the removal of the organophosphate group, restoring the enzyme's activity. This allows for the proper breakdown of acetylcholine, reducing the overstimulation of acetylcholine receptors.

Pharmacodynamics

The pharmacodynamics of oximes involve their ability to penetrate biological membranes and effectively interact with the active site of acetylcholinesterase. They enhance the hydrolysis of acetylcholine, leading to a decrease in its synaptic concentration. This action counteracts the cholinergic symptoms seen in organophosphate poisoning, such as respiratory distress, muscle twitching, and other autonomic dysfunctions.

Pharmacokinetics

Oximes are typically administered intravenously or intramuscularly and are absorbed into the systemic circulation. Their distribution is influenced by their lipophilicity, and they are capable of crossing the blood-brain barrier. Metabolism of oximes occurs primarily in the liver, and they are excreted in the urine. The half-life can vary depending on the specific oxime used and the route of administration.

Pregnancy

There is limited data on the use of oximes during pregnancy. They should be used only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is not known whether oximes are excreted in human milk. Caution should be exercised when administering to breastfeeding women.

Storage

Store in a cool, dry place, away from light. Specific storage conditions may vary based on the formulation.

Mechanism of action

... Milbeknock acts on the nervous system mediated with inhibitory neurotransmitter, GABA (g-Amino butyric acid). /Milbeknock/