Posted by ed_uk on July 29, 2005, at 15:32:42
In reply to Re: Nardil and asthma meds.? » ed_uk, posted by zero on July 29, 2005, at 12:35:19
Hi Zero,
>Would you happen to have a link to further explanation of that last paragraph (below)?
I don't have a link because I got my info from a texbook - Stockley's Drug Interactions.
Sympathomimetics can be divided into two main groups: directly-acting and indirectly-acting.
A directly-acting sympathomimetic is a drug which directly stimulates adrenergic receptors itself. An indirectly-acting sympathomimetic is a drug which releases NE from nerve endings.
Most directly-acting sympathomimetics do not interact with MAOIs. The selective beta-2 agonists are an example of directly-acting sympathomimetics which do not appear to interact with MAOIs.
Most indirectly-acting sympathomimetics (eg. amphetamine, ephedrine, phenylpropanolamine etc) *do* interact with MAOIs. MAOIs cause NE to accumulate inside the nerve endings of the sympathetic nervous system. NE is therefore released in abnormally large quantites if a patient on an MAOI takes an indirectly-acting sympathomimetic: hence the drug interacion. Directly-acting sympathomimetics do not release NE, hence the absense of a clinically significant interaction.
Btw, some sympathomimetic drugs are metabolised by MAO, these drugs will interact with MAOIs. I don't know how albuterol and salmeterol are metabolised, I'd have to look it up.
If you decide to combine Serevent with an MAOI, start at low doses and increase gradually.
~Ed
poster:ed_uk
thread:534537
URL: http://www.dr-bob.org/babble/20050728/msgs/535343.html