Your student is seeing patients with you. Their first patient is a 72 y/o patient in for their every 6 months appointment. The patient complains of constipation but no other changes in their general health.

Their physical exam and vitals signs are WNL. Their labs are normal and they have no allergies. The only medications they take on a regular basis are amitriptyline 25mg po QHS (for sleep) and chlorpheniramine 4mg po QHS (for seasonal allergies).

The student writes off the constipation as 'just being old' and wants you to renew their prescriptions and sign off his note.

Do you sign off or not? Why or why not?

SELECT  here for discussion

** THANKS to MAJ (Dr.) Libby Schindler for her help with this Pearl.**

Probably not... at least not yet.

Granted, constipation can be caused by a multitude of things including various pathologies, poor diet, lack of fiber, too little water, too little exercise, etc. etc. For the purposes of this discussion, we're attributing the constipation to the anticholinergic effects of both their prescription medications, the amitriptyline [Elavil®] and the chlorpheniramine [CTM or Chlor-Trimeton®].

Elderly patients have decreased acetylcholine (ACh) levels at baseline, compared to normal patients at 20 or 30 years of age. They are already in a relative anticholinergic state. This places them at greater risk for anticholinergic effects, even without anticholinergic drugs on
board.

Tricyclic antihistamines have a strong anticholinergic effect. (remember anticholinergic effects - Dry as a bone, Blind as a bat, Crazy as a loon, among others). Besides dry mouth and urinary retention (another problem esp in elderly males) constipation can be significant. The 'first generation' antihistamines have a pretty strong anticholinergic effect themselves. People taking these chronically often over come or get used to the sedative properties but not the anticholinergic effects.

What alternatives can we offer this patient besides good sleep hygiene? For sleep, low dose zolpidem [Ambien®] or zaleplon [Sonata®] may also work in this patient. Trazodone [Desyrel®], a serotonergic/antihistaminic antidepressant, might be appropriate. A low dose benzodiazepine (without an active metabolite nor long half-life) like lorazepam or oxazepam might be appropriate. Benzodiazepines with long half-lives and/or active metabolites (flurazepam [Dalmane®], chlordiazepoxide [Librium®], diazepam [Valium®]) are best avoided in this population. The elderly are especially sensitive to benzodiazepine effects such as decreased concentration, decreased memory, and in rare cases, delirium. Also, either during the night or upon rising these agents may impair mentation and/or balance, predisposing them to falls (esp risky in the elderly who may have underlying osteoporosis). Avoid diphenhydramine [Benadryl®] because it has similar anticholinergic properties and adversely affects sleep architecture.

For allergies, one of the newer 'second generation' antihistamines would work well. Loratadine is available generically, over-the-counter, and is non-sedating. It has minimal anticholinergic effects. More expensive, prescription only, non-sedating antihistamines include fexofenadine [Allegra®] and desloratadine [Clarinex®].

When treating elderly patients, the general rule is 'start low and go slow'. There are drugs which should be avoided in elderly patients and drugs that should be avoided with certain concomitant diseases. Beers list of drugs (see attached) is a published of both these categories. It lists what drugs should be avoided in the elderly, what the problem(s) are with these drugs, and how severe the effects are. It also lists what drugs to avoid in elderly patients with concurrent diseases.

This Pearl is meant for academic and educational purposes only. This Pearl is meant to raise important points regarding the safe and cost-effective pharmacotherapy of patients. It is not meant to be the definitive reference for the treatment or prophylaxis of various diseases. Although every effort is taken to ensure this Pearl is correct and factual, errors may occur. The US Air Force, the 59th Medical Wing (MDW), and 59th MDW Pharmacy assume no liability for incorrect information or harm that may occur from the use of the information included in this Pearl.