Zoletil Injection

Indications

• Induction of anesthesia in veterinary procedures
• Sedation for diagnostic imaging
• Surgical anesthesia in animals

Dosage

Children: Specific pediatric dosing information is not available, consult veterinary references for appropriate dosing in young animals.

Adults: Dosage varies by species and procedure, refer to veterinary guidelines for specific dosing recommendations.

Mechanism of action

Tiletamin acts primarily as an NMDA receptor antagonist, inhibiting the excitatory neurotransmitter glutamate at these receptors. This action leads to dissociation between the thalamocortical and limbic systems, resulting in a state of anesthesia characterized by analgesia and altered sensory perception.

Pharmacodynamics

The pharmacodynamic effects of tiletamin include sedation, analgesia, and muscle relaxation. Its dissociative properties mean that while the patient may be unresponsive to external stimuli, some autonomic functions and reflexes may remain intact. The onset of action is rapid, typically occurring within minutes of administration, and the duration of effect can vary based on the dose and route of administration.

Pharmacokinetics

Tiletamin is rapidly absorbed when administered intravenously or intramuscularly, with peak plasma concentrations occurring shortly after administration. It undergoes hepatic metabolism and is excreted primarily via the kidneys. The elimination half-life can vary based on the species and dosage used. Due to its rapid onset and short duration of action, tiletamin is often used in combination with other sedatives or anesthetics to achieve prolonged effects.

Contra-indications

• Hypersensitivity to tiletamin or any component of the formulation
• Severe cardiovascular disease
• Severe hepatic or renal impairment
• Concurrent use with other anesthetics or CNS depressants

Adverse effects

• Respiratory depression
• Cardiovascular instability
• Muscle rigidity
• Ataxia
• Hyperthermia
• Hallucinations
• Vomiting
• Increased salivation

Interactions

• Caution in use with other central nervous system depressants
• May interact with anticholinergic agents
• Potential additive effects with opioids
• Use with caution in conjunction with anesthetics

Precautions

• Use with caution in patients with pre-existing respiratory or cardiovascular conditions
• Monitor cardiovascular and respiratory function during and after administration
• Ensure proper hydration and electrolyte balance
• Consider using adjunct medications to mitigate side effects like muscle rigidity

Pregnancy

Safety in pregnancy has not been established. Use only if the potential benefit justifies the potential risk to the fetus.

Breast-feeding

It is not known if tiletamin is excreted in human milk. Caution is advised when administering to nursing mothers.

Storage

Store in a cool, dry place away from light. Keep out of reach of children. Do not freeze.

Formulations

• Injectable solution

Indications

• Anxiety disorders
• Sedation
• Muscle relaxation
• Pre-anesthetic medication

Dosage

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

Adults: Refer to specific guidelines and the BNF for appropriate dosing recommendations.

Mechanism of action

Zolazepam functions by modulating the activity of gamma-aminobutyric acid (GABA) at the GABA-A receptor, enhancing the inhibitory effects of GABA, which results in increased neuronal hyperpolarization and decreased excitability. This mechanism underlies its anxiolytic, hypnotic, and muscle relaxant effects.

Pharmacodynamics

The pharmacodynamic profile of zolazepam includes sedation, anxiolysis, muscle relaxation, and anticonvulsant effects. It produces its effects relatively quickly, leading to rapid onset of sedation. The duration of action can vary based on the dose and the presence of other medications.

Pharmacokinetics

Zolazepam is well-absorbed following administration, with peak plasma concentrations typically occurring within a few hours. It is metabolized in the liver, with metabolites that may have pharmacological activity. The elimination half-life can vary, influencing the duration of sedation and therapeutic effects. Excretion occurs primarily through the kidneys.

Contra-indications

• Hypersensitivity to zolazepam or any of its components
• Severe respiratory insufficiency
• Myasthenia gravis
• Severe hepatic impairment

Adverse effects

• Sedation
• Dizziness
• Hypotension
• Ataxia
• Confusion
• Paradoxical reactions
• Dependence and withdrawal symptoms

Interactions

• Caution with other CNS depressants such as alcohol, opioids, and sedative-hypnotics
• May enhance the effects of drugs that cause sedation
• Potential for increased side effects when combined with other medications that affect liver enzymes

Precautions

• Use with caution in patients with a history of substance abuse
• Monitor for signs of respiratory depression
• Assess for potential interactions with concomitant medications
• Consider lower doses in elderly patients or those with compromised hepatic function

Pregnancy

Zolazepam should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. It is classified as a Category C drug.

Breast-feeding

Zolazepam is excreted in breast milk. Caution is advised when administering to nursing mothers.

Storage

Store in a well-closed container at room temperature, away from light and moisture.

Formulations

• Tablets
• Injectable solution