Propofol (2,6-diisopropylphenol) is an intravenous anaesthetic agent used for induction and maintenance of general anaesthesia. IV administration of propfol is used to induce unconsciousness after which anaesthesia may be maintained using a combination of medications. It is extensively metabolized, with most of the administered dose appearing in the urine as glucuronide conjugates. Favorable operating conditions and rapid recovery are claimed as the main advantages in using propofol, whereas disadvantages include a relatively high incidence of apnea, and blood pressure reductions. The action of propofol involves a positive modulation of the inhibitory function of the neurotransmitter gama-aminobutyric acid (GABA) through GABA-A receptors. Due to its high lipid-solubility, propofol was initially formulated as a solution with the surfactant Cremophor EL, but the occurrence of pain on injection and anaphylactoid reactions prompted to search for alternative formulations. Results from using cyclodextrins, water-soluble prodrugs, and adopting Bodor's approach to the site-specific chemical delivery system (CDS), as well as the advantages provided by computer-controlled infusion systems, are examined in some detail.

Tricaine (MS-222, Tricaine-S), a water-soluble local anesthetic, is used commonly for sedation, immobilization, and anesthesia of poikilothermic animals and has been accepted as a common anesthetic for use in the cold-blooded animals. It has long been recognized as a valuable tool for the proper handling of these animals during manual spawning (fish stripping), weighing, measuring, marking, surgical operations, transport, photography, and research. Tricaine was developed by Merck as a sulfonated analog of benzocaine with high solubility in water. The main advantage of Tricaine is the short duration of action and rapid metabolism. There are many reports describing the use of Tricaine for anesthetizing poikilothermic animals because it is a safe agent for immersion anesthesia even though the other anesthetics such as ether, ethanol, thiopental, halothane, isoflurane, barbiturates also could be used. Amphibians could be anesthetized easily by immersion methods with Tricaine because the amphibian skin is extremely permeable and water is absorbed through the skin rather than ingested. Tricaine has been administered as an injectable agent also.

Clove oil is a natural product, derived from the Eugenia caryophyllata tree. Clove oil is 85 to 95% eugenol. Isoeugenol and methyleugenol make up 5 to 15% of the remaining ingredients. Isoeugenol is manufactured from eugenol by a process of isomerization. Isoeugenol have been used in foods and eugenol has been used in animal feeds. Isoeugenol is used as a fish anesthetic. The mechanism of action of isoeugenol in fish has not been determined. It is hypothesised that its effects are mediated via receptors controlling cellular ion channels in a similar way to that described for local anaesthetics. Reports of adverse reactions involving the use of isoeugenol in humans are primarily confined to incidents of contact sensitization or allergy following dermal exposure.