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→The Azoles
==The Azoles==
==The Azoles==
These are synthetic '''fungistatic''' agents that interfere with ergosterol formation, this results in the fungal cell being uncapable to divide. It is very broad spectrum, but unfortunately the formation of ergosterol is very similar to the synthesis of mammalian sterols and hence has a very narrow therapeutic range.
There are two groups of azoles; imidazoles and triazoles. They differ thanks to an addition of a triazole ring, this results in the triazoles having greater half-lives, lower toxicity and potentially increased anti-fungal activities.
===Imidazoles===
'''Enilconazole'''
* It is not absorbed after oral dosing and so has a wide safety margin.
* It is only liscensed for topical ringworm treatment, but has been used off-liscense (following the cascade) for ''Malassezia pachydermatitis'' infections and nasal aspegillosis.
'''Ketaconazole'''
* It has good oral bioavailability if given with food; it needs an acidic pH to be absorbed.
* It is metabolised by the liver into inactive compounds that are then excreted in bile.
* It has been used for deep mycoses therapy, treatment of ringworm and nasal aspergillosis.
* Toxicity is low but can result in inappetance, pruritis, alopecia and lightening of hair.
* It has been known to be tetragenic and embryotoxic and so shouldn't be used with pregnant animals.
===Triazoles===
'''Itraconazole'''
* It is more potent than ketaconazole but likewise needs an acidic environment to be absorbed, and has a wider spectrum of activity.
* It is eliminated by hepatic metabolism.
* It is used mainly to treat systemic fungal infections.
* Can cause anorexia and hepatic toxicity in dogs. If this occurs, stop therapy until appetite returns and then continue treatment at half the dose.