Conditions: Pain
Keywords: fingerstick opioid heelstick loperamide topical opioid
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 34
Healthy volunteers: yes

Brief summary:
This study evaluates topical loperamide 5% gel in reducing pain during repeat finger lancing (finger stick) in healthy adults. Half of participants received 5% loperamide gel applied to their fingertip prior to their second lance and the other half received the gel only.

Detailed description:
Lancing the finger and heel to obtain capillary blood for specimen collection and diagnostic testing is a painful and tissue damaging procedure. With each lance, there is direct splicing of capillaries along with free nerve endings resulting in an immediate localized pain response and hyperalgesia from the release of pain producing substances. Opioid agonists (morphine, fentanyl, loperamide) have demonstrated significant analgesia when locally injected or topically applied to a site of inflammation/injury in animal models.

Loperamide, a piperdine derivative with a structure similar to the synthetic opioid meperidine, has strong affinity for Mu opioid receptors. It was approved by the FDA in 1969 as an anti-diarrheal agent with Mu opioid activity mimicked the constipating effects of other opioids, but with markedly reduced CNS effects due to its affinity for p-glycoprotein, preventing crossing the blood brain barrier (BBB) under normal circumstances.

This prospective, double-blind, repeated measures, randomized investigational new drug trial used loperamide developed as a topical gel in 34 adult participants to determine its analgesic effects during repeat finger lancing. The investigators also assessed for any local skin reaction to the gel application and for any constipation or abdominal cramping which might be evidence of systemic absorption and Mu opioid agonist activity on the gut.

This study would be applicable for use in 28.9 million adults who are diabetic and require finger lancing for blood glucose monitoring and the high risk newborn population who require repeat heel lancing for specimen collection.

Arms:
arm 1: Participants received 5% loperamide gel (0.2gm equivalent to 10 mg) applied following a single surgilance to the 5th digit. The loperamide gel was applied 10 minutes following the first lance, rubbed in for one minute within an 8 mm mold surrounding the lance site. The mold was removed and the gel was covered with a transparent occlusive dressing and left in place for 30 minutes. The forearm was also swabbed with the loperamide gel which was left in place for 30 minutes. The placebo gel contained the same ingredients without the loperamide. The loperamide gel formulation includes: Loperamide 5%, Propylene Glycol; Ethanol (190 proof USP); Ethyl acetate; and Klucel HF 1%. arm 2: Participants received placebo gel (0.2gm) applied following a single surgilance to the 5th digit. The placebo gel was applied 10 minutes following the first lance, rubbed in for one minute within an 8 mm mold surrounding the lance site. The mold was removed and the gel was covered with a transparent occlusive dressing and left in place for 30 minutes. The forearm was also swabbed with the placebo gel which was left in place for 30 minutes. .The placebo gel contained the same ingredients without the loperamide. The placebo gel formulation includes: Propylene Glycol; Ethanol (190 proof USP); Ethyl acetate; and Klucel HF 1%.

Interventions: intervention 1: Loperamide intervention 2: Drug, placebo gel
Intervention descriptions: intervention 1: Following lance one, 0.2 grams of loperamide 5% gel was applied from a sterile syringe to the participants previous lance site within an 8 mm diameter circular plastic mold. The loperamide gel was rubbed lightly on the skin surface for one minute using a gloved finger swirled into the mold site. The mold was removed and the site was covered with a transparent occlusive dressing for 30 minutes. At 30 minutes the gel was removed with gauze, the skin cleaned with an alcohol wipe and the second lance was done within the same location as the first. The loperamide gel was also swabbed to the forearm within the 8 mm mold and left in place for 30 minutes. intervention 2: Following lance one, 0.2 grams of gel alone was applied to the participants previous lance site within an 8mm diameter circular plastic mold. The gel was rubbed lightly on the skin surface for one minute using a gloved finger swirled into the mold site. The mold was removed and the site was covered with a transparent occlusive dressing left in place for 30 minutes. At 30 minutes the gel was removed with gauze, the skin cleaned with an alcohol wipe and the second lance was done within the same location as the first. The placebo gel was also swabbed to the forearm within the 8 mm mold and left in place for 30 minutes.

Protocol document: