Tetracycline Ergotamine

ERGOT DERIVATIVES TETRACYCLINES Cases of ergotism with tetracyclines and ergotamine Uncertain Avoid co-administration. If absolutely necessary, advise patients to discontinue treatment immediately if numbness and tingling of the extremities are felt... 

Other cases of ergotism, some of them more severe, have been described in two patients taking ergotamine tartrate and doxycycline, and in 3 patients taking tetracycline-containing preparations. - ... 

Information is very limited indeed. The incidence and general importance of this interaction is uncertain, but it would clearly be prudent to be on the alert for signs of ergotism in any patient given ergot derivatives and a tetracycline. However, note that one of the manufacturers of ergotamine actually recommends that the concurrent use of tetracycline should be avoided. Impairment of liver function may possibly be a contributory factor in this interaction. 

An example of a simple oxidatiim reaction is the craiver-sion of Fe " into Fe. Examples of active substances that are prone to oxidation are acetylcystein, adrenaline, apomorphine, clioquinol, dithranol, dobutamine, ergotamine, hydroquinone, isoniazid, mesalazine, naloxone, neomycin, oxycodone, paracetamol, peptides, salbutamol, phenothiazine derivatives (promazine, promethazine, chlorpromazine), phenylephrine, physostigmine, tetracycline, tretinoin, the vitamins A and D, and the excipients flavouring agents, fragrances and unsaturated fats (vegetable oils, suppository bases). 

A well-known example of isomerisation is the conversion of ergotamine into ergotaminine and, if the other carbon atom also is affected, in aci-ergotamine. Other active substances that degrade by isomerisation are adrenaline, colecalciferol, ergometrine, pilocarpine and tetracycline. 

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