Dear Editor,

First, I wish to congratulate you and your team for a superb magazine. I much enjoy the reading and find the articles of high quality.

I am surprised, however, by seeing in this Canadian publication frequent use of non-SI units. For example, in a recent publication (July 2009), the serum-ascites albumin gradient is reported in g/dl, while I would expect the units to be in g/L; the serum creatinine is reported in mg/dl, while in Canada we are familiar with µmol/L. As you know, the conversion from one unit to the other is not always an easy calculation. I recommend universal use of SI units in documents, for easier knowledge translation and adaptation to clinical practice. If needed, the other unit values could be put in parentheses.

Thanks again for the great publication.

Céline Léger-Nolet, FRCPC
New Liskeard, ON

Editor’s Reply

Dear Dr. Léger-Nolet,

Thank you for your kind words about our journal. We agree that SI units are the preferred unit of measurement, and we will do our best to ensure that they are the standard in our future issues.

Sincerely,

Barry Goldlist, MD, FRCPC, FACP, AGSF
Editor-in-Chief

To the Editor:

I must congratulate Glaser and Rolita on covering an important and challenging area of medication practice in the March 2009 issue of Geriatrics & Aging. However, I do have a couple of questions/comments:

1. The authors mentioned simethicone within the class of antacid medications, but my understanding is that its mechanism of action is to alter the surface tension of gas bubbles produced during the digestion of food. It is safe in older adults but has no impact on gastric acid or heartburn per se.
2. Could you please clarify which drug interactions are similar between proton pump inhibitors and H2-blockers? My understanding was that the latter, particularly older drugs such as cimetidine, had significantly more drug interactions than PPIs.
3. I understood loperamide had anticholinergic properties and might not be very safe in patients with moderate dementia.
4. Among laxatives, lactulose is an osmotic laxative but is it not safe in renal failure? Plus a previous article in Geriatrics & Aging suggested that docusate sodium is not very effective in the treatment of constipation.

Please comment.

Sincerely,
A Physician*
*The author of the letter has requested anonymity.

The authors respond:

In response to the query on Educating the Older Adult in Over-the-Counter Medication Use, simethicone is a surfactant and may modulate gas handling. Simethicone is taken to reduce gas, as it acts in the stomach and intestines to change the surface tension of gas bubbles. Although it is generally considered to be of no specific value in functional dyspepsia, recent trials have shown that it helps with the overall improvements of functional dyspepsia. When compared to cisapride, simethicone was superior in the treatment of patients with functional dyspepsia.¹

Proton pump inhibitors are generally well tolerated with few side effects. However, they have the same drug interactions as H2RAs but are less reported. These are listed under H2RAs in Table 4 of Educating the Older Adult in Over-the-Counter Medication Use, and include fluoxetine, chemotherapy drugs, theophylline, warfarin, carbamazepine, phenytoin, isoniazid, ciprofloxacin, ketoconazole, and valproic acid. Cimetidine has been associated with acute liver disease more frequently than other H2RAs.² The most serious interaction is the risk of parkinsonism with a combination of fluoxetine and cimetidine.³

The nonopioid actions of loperamide contributes to the reduction of acetylcholine release from human cholinergic nerves.⁴ Older adults are at greater risk for increased cholinergic load when multiple drugs with anticholinergic activity are used.⁵ Taking other medications with anticholinergic properties or having an underlying cognitive dysfunction, such as moderate dementia, makes an older adult particularly susceptible to these side effects.

Docusate sodium is a surfactant laxative. Controlled clinical trials of docusate sodium are limited. The mechanism of action is to allow penetration of water and fat into feces. It is generally slow to work⁶ yet is generally safe and a good first line of therapy, especially for patients who suffer from hard stools as the underlying cause of their constipation. The inquirer is right in pointing out that docusate sodium is not the most effective agent for the treatment of constipation, but it is safe and works well with hard stools. Psyllium has been shown to be superior to docusate sodium in the treatment of chronic constipation, as it results in significant improvement in evacuation completeness.⁷ Polyethylene glycol is also relatively safe to use and is now available over the counter as Miralax. Lactulose is an established therapy for hepatic encephalopathy and shows effectiveness for constipation. Lactulose can result in electrolyte abnormalities in high doses and more so in patients of renal failure so this should be closely monitored by a physician if the patient takes it regularly.

Judith Glaser, DO and Lydia Rolita, MD

References:

1. Holtmann G, Gschossmann J, Mayr P. A randomized placebo-controlled trial of simethicone with cisapride for the treatment of patients with functional dyspepsia. Aliment Pharmacol Ther 2002;16:1641-8.
2. Garcia Rodriguez LA, Wallander MA, Stricker BH. The risk of acute liver injury associated with cimetidine and other acid-suppressing anti-ulcer drugs. Br J Clin Pharmacol 1997;43:183-8.
3. Leo R, Lichter D, Hershy L. Parkinsonism associated with fluoxetine and cimetidine: A Case Report. Journal of Geriatric Psychiatry and Neurology 1995;8:231-3.
4. Burleigh D. Opioid and non-opioid actions of loperamide on cholinergic nerve function in human isolated colon. Eur J Pharmacol 1998;152:39-46.
5. Kay G, Pollack BG, Romanzi LJ. Unmasking cholinergic load: When 1+1=3. CNS Spectrums 2004;15:1-11.
6. Tally T. Evaluation of drug treatment in Irritable Bowel Syndrome. Br J Clin Phramacol 2003;56:362-9.
7. McRorie J, Daggy B, Morel J. Psyllium is superior to docusate sodium for the treatment of chronic constipation. Aliment Pharmacol Thera 1998:12 491-7.

The authors respond:
There appears to be no specific effect of aging on bowel function. It is more likely the cumulative result of decreased mobility, comorbid illness, and medication side effects that cause a higher incidence of constipation among older adults.¹

While it is true that lactulose can be an effective osmotic laxative, the fact remains that it may also lead to painful abdominal cramping and flatus.² For this reason, it is recommended as a second or third line laxative, usually in combination with other medications.

Hershl Berman, Shawna Silver, Laura Brooks

References

1. Salles N. Basic mechanisms of the aging gastrointestinal tract. Dig Dis 2007;25:112-7.
2. Hsieh C. Treatment of constipation in older adults. Am Fam Physician 2005;72:2277-85.

To the Editor:

Could the authors of the February 2007 article “Peptic Ulcer Disease in Older Adults” (Geriatrics Aging 2007;vol. 10, no. 2:77-83) please comment in a bit more detail on the evidence supporting the statement that “it would be prudent not only to switch to a COX-2 inhibitor but also to add a PPI” (p. 82, section on NSAIDs, last sentence).

Toronto Physician

Drs. Constantine A. Soulellis and Carlo A. Fallone respond:

To our knowledge, the issue of concurrent usage of COX-2 inhibitors and proton pump inhibitors (PPIs) has been explored in the literature only once before;1,2 this was a negative study that failed to demonstrate superiority of COX-2 inhibitors/PPIs over nonselective NSAIDs/PPIs in high-risk GI patients. However, we would like to disclose that we are privy to the results of a large retrospective cohort study conducted at McGill University and the University of Montreal that included over two million registered prescriptions for COX-2 inhibitors, nonselective NSAIDS, PPIs, and every combination thereof. The findings, to be published in an upcoming issue of Arthritis and Rheumatism (July 2007),3 demonstrate a clear reduction in the studied outcome (hospitalizations from perforated or bleeding ulcers) for COX-2 inhibitors plus PPIs compared to COX-2 inhibitors alone for ages greater than 75. COX-2 inhibitors and PPIs were also found to be superior to nonselective NSAIDs and PPIs for the same measured outcomes.

I hope this explanation is satisfactory for your readers. Again, thank you kindly for affording us the opportunity to contribute to Geriatrics & Aging.

Regards,
C. A. Fallone and C. A. Soulellis

References

1. Cryer B. A COX-2-specific inhibitor plus a proton-pump inhibitor: is this a reasonable approach to reduction in NSAIDs’ GI toxicity? Am J Gastroenterol 2006;101:711-3.
2. Scheiman JM, Yeomans ND, Talley NJ et al. Prevention of ulcers by esomeprazole in at-risk patients using non-selective NSAIDs and COX-2 inhibitors.  Am J Gastroenterol 2006;101:701-10.
3. Rahme E, Barkun AN, Toubouti Y, et al. Do proton pump inhibitors confer additional gastrointestinal protection in patients given celecoxib? Arthritis Rheum 2007;57. In press.

The article "SPECT May Help Resolve Dementia Diagnosis," in the January/February issue fails to mention EEG in diagnosis of dementia, a test cheaper than SPECT and CT. EEG is quite sensitive, correlates with prognosis, and is specific withing a given clinical context.

Your title "May Help Resolve" may generate unnecessary referrals for SPECT scanning in this situation. At a time of rigorous health care funding, we need to utilise only those tests which are clearly going to benefit the patient in a cost-effective manner. This article does not advance that goal.

Sincerely,

Warren T. Blume, MD, FRCPC,
Professor,
Department of Clinical Neurological Sciences,
Epilepsy and Clinical Neurological Sciences,
London Health Sciences Centre,
London, Ontario

P.S. The cost of EEG versus SPECT scanning is $51.20 and $162.50 respectively.