Posted by King Vultan on April 30, 2004, at 12:35:22
In reply to Nardil anticholinergic vs. adrenergic SEs, posted by Questionmark on April 30, 2004, at 3:54:28
> 1) DO MAOIs (esp. Nardil) have anticholinergic properties?The consensus from everything I've read is yes, Nardil is thought to have slight/moderate anticholinergic effects. Parnate is thought to have fewer or none.
> 2) Are there adrenergic effects that can be subjectively similar or identical to anticholinergic effects?
Absolutely. Drugs that increase norepinephrine transmission such as MAOIs, selective NE reuptake inhibitors (Strattera, desipramine), or drugs that increase NE transmission in combination with other neurotransmitters (Effexor, Wellbutrin) can generate "pseudo" anticholinergic effects. These effects are not true anticholinergic effects such as one might get from drugs like amitriptyline or imipramine where you do see substantial blockade of muscarinic acetylcholine receptors but rather, side effects that mimic them from the effects on the noradrenergic system. Stahl "Essential Psychopharmacology" states that "This is not due to direct blockade of muscarinic acetylcholine receptors but to indirect reduction of net parasympathetic tone resulting form increased sympathetic tone. Thus a "pseudo-anticholinergic" syndrome of dry mouth, constipation, and urinary retention may be caused by selective NRIs, even though they have no direct actions on cholinergic receptors. Usually, however, the indirect reduction of cholinergic tone yields milder and shorter lasting symptoms than does direct blockade of muscarinic cholinergic receptors."This has also been my experience. When I was on desipramine, a selective and relatively powerful NE reuptake inhibitor, which has weak anticholinergic properties similar in absolute terms to those of Paxil, I experienced moderate dry mouth, constipation, and urinary hesitation. When I switched to Vivactil (protriptyline), another fairly strong NE reuptake inhibitor but one that is universally regarded as substantially more anticholinergic, the side effects I had suffered on desipramine continued but became noticeably worse. I also began suffering from prostate issues, erectile dysfunction, and blurry vision, all of which were the result of the brutal anticholinergic effects of the Vivactil. I found the erectile dysfunction particularly unacceptable and wound up dumping the drug not too long after realizing what was going on.
Todd
poster:King Vultan
thread:341646
URL: http://www.dr-bob.org/babble/20040429/msgs/341816.html