Medication Prescribing

Pearls of Wisdom: Pharmacotherapy for Substance Misusers

Question: Alfredo is a 37-year-old who comes to the emergency department complaining of renal colic. Note: Alfredo is a “frequent flyer” in the emergency department and many staff members know him by name.

In addition to past admissions for opioid overdose, acute myocardial infraction secondary to cocaine use, and multiple visits for infected illicit substance injection sites, Alfredo also has recurrent nephrolithiasis.

On his most recent visit for “alleged” kidney stones, Alfredo was observed pricking his finger to add a little gratuitous blood to his urine sample; he was seeking an opioid prescription to alleviate his renal colic.

For a patient who has known nephrolithiasis, which non-narcotic medical therapy that might help with pain control?

  1. Desmopressin (DDAVP)
  2. Diphenhydramine (Benadryl)
  3. Depo-medroxyprogesterone acetate (DepoProvera)
  4. Nebivolol (Bystolic)

What is the correct answer?
(Answer and discussion on next page)

 

Louis Kuritzky, MD, has been involved in medical education since the 1970s. Drawing upon years of clinical experience, he has crafted each year for almost 3 decades a collection of items that are often underappreciated by clinicians, yet important for patients. His “Pearls of Wisdom” as we like to call them, have been shared with primary care physicians annually in an educational presentation entitled 5TIWIKLY (“5 Things I Wish I Knew Last Year”…. or the grammatically correct, “5 Things I Wish I’d Known Last Year”).

Now, for the first time, Dr Kuritzky is sharing with the Consultant360 audience. Sign up today to receive new advice each week.

 

    Answer: Desmopressin (DDAVP)

    For pain-experienced persons, the pain of labor, gout, and ureteral colic are ranked at the top. Some substance abusers are sufficiently sophisticated that they can fool us into prescribing opioids for legitimate diagnoses that they know how to simulate. Our patient, Alfredo, knows just what to say and do to prompt a clinician to provide opioid therapy for pain relief. Discovery of his falsification of the urine testing by pricking his own finger might likely have gone undetected had it not been for video surveillance.

    Is there pharmacotherapy we could use that might provide not only pain relief, but also avoidance of the potential for substance abuse? After all, although Alfredo is a known substance abuser, we cannot neglect syndromes in which his pain merits intervention.

    Treatment

    The first inklings of a potential for desmopressin to have a role in renal colic came as a result of the observation that desmopressen produces a decreases in muscular contractions of the renal pelvis. A pilot trial found that desmopressin alone provided complete relief of renal colic pain in almost half of patients. When followed with diclofenac, over 90% of renal colic patients achieved relief.1 Because this trial was not randomized, further testing is necessary to confirm whether desmopressin could indeed be efficacious.

    To clarify the issue, a clinical trial by Lopes et al2 compared desmopressin nasal spray, diclofenac injection, or the combination for patients with renal colic. Although diclofenac was superior to desmopressin, there was some benefit seen with the addition of the desmopressin.

    Desmopressin and Renal Colic2

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    Fortunately, we have numerous tools to reduce the pain of renal colic. Alpha-blockers (eg, terazosin, doxazosin, tamsulosin) have been shown to reduce spasm induced by renal colic, but preserve peristalsis—thereby enhancing stone passage and reduction of painful spasm. Opioids are effective for pain relief, but when a situation arises that makes us dubious about their appropriate use, it’s good to have some alternatives to consider.

    What’s the “Take Home”?

    Substance abusers may utilize subterfuge to obtain controlled substances. Of course, we do not want to deny analgesia when any patient suffers pain. Desmopressin may offer an option to treat renal colic prior to having to take the step to opioid analgesia.

    References:

    1. Zahibi N, Teichman JMH. Dealing with the pain of renal colic. Lancet. 2001;358(9280):437-438.
    2. Lopes T, Dias JS, Marcelino J, et al. An assessment of the clinical efficacy of intranasal desmopressin spray in the Rx of renal colic. Brit J Urol. 2001;87(4):322-325.