ISONOR GRANULES 6.2g (Each 6.2g contains Isometamidium Hcl 1g/Antipyrine 5.2g)

Indications

• Pain relief
• Fever reduction
• Assessment of drug metabolism

Dosage

Children: Refer to the BNF for Children for specific dosing recommendations for paediatric patients.

Adults: Refer to the BNF for specific dosing recommendations for adults.

Mechanism of action

Antipyrine acts primarily in the central nervous system (CNS) by increasing the pain threshold. It achieves this by inhibiting both isoforms of cyclooxygenase, COX-1, COX-2, and COX-3, which are enzymes involved in the synthesis of prostaglandins (PGs).

Pharmacodynamics

As an analgesic and antipyretic, antipyrine effectively reduces pain and fever. It is administered orally and via ear drops, and is frequently used in clinical settings to evaluate the effects of various drugs or diseases on hepatic drug-metabolizing enzymes.

Pharmacokinetics

Antipyrine is well absorbed from the gastrointestinal tract and undergoes extensive hepatic metabolism. Its elimination half-life varies, influenced by hepatic function and other factors. The drug is primarily excreted in urine as metabolites.

Adverse effects

• Nausea
• Vomiting
• Rash
• Dizziness
• Headache

Precautions

• Use with caution in patients with liver impairment
• Monitor for signs of allergic reactions
• Consider potential interactions with other medications affecting liver enzymes

Pregnancy

Antipyrine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

Caution is advised when administered to breastfeeding mothers due to the lack of data on excretion in human milk.

Storage

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

Formulations

• Oral tablets
• Ear drops

Indications

• Trypanosomiasis in cattle
• Prevention of African sleeping sickness in livestock

Dosage

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

Adults: Refer to the BNF for specific dosing guidelines as it varies based on the condition and species treated.

Mechanism of action

Isometamidium acts by intercalating into the DNA of the parasite, disrupting replication and transcription processes. This impairs the synthesis of essential proteins and nucleic acids, leading to the death of the trypanosome.

Pharmacodynamics

The pharmacodynamics of isometamidium involve its selective toxicity to trypanosomes, which are more susceptible to its effects compared to mammalian cells. The drug's high affinity for the DNA of the parasites ensures that it efficiently inhibits their growth and replication. The efficacy of isometamidium is influenced by factors such as the strain of the trypanosome and the pharmacokinetic profile of the drug.

Pharmacokinetics

Isometamidium is administered parenterally, and it exhibits a relatively long half-life, allowing for sustained therapeutic levels in the bloodstream. The drug is distributed widely in body tissues, including the liver and kidney, where it can exert its effects against the parasites. It is metabolized in the liver and excreted primarily through urine, although specific metabolic pathways remain to be fully elucidated.

Pregnancy

Isometamidium should only be used if the potential benefit justifies the potential risk to the fetus. Consult relevant guidelines for use during pregnancy.

Breast-feeding

The effects on breastfeeding infants are unknown. Caution is advised when administering to nursing mothers.

Storage

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

Mechanism of action

Antipyrine is thought to act primarily in the CNS, increasing the pain threshold by inhibiting both isoforms of cyclooxygenase, COX-1, COX-2, and COX-3 enzymes involved in prostaglandin (PG) synthesis.

Pharmacodynamics

Antipyrine is an analgesic and antipyretic that has been given by mouth and as ear drops. Antipyrine is often used in testing the effects of other drugs or diseases on drug-metabolizing enzymes in the liver. (From Martindale, The Extra Pharmacopoeia, 30th ed, p29)