E L Vander Tuin | PubMed Health

PubMed1997

Effect of two aspirin pretreatment regimens on niacin-induced cutaneous reactions.

OBJECTIVE: To compare the effects of pretreatment with two aspirin regimens and placebo on niacin-induced cutaneous reactions. DESIGN: Randomized, double-blind, placebo-controlled, crossover study. SETTING: Internal medicine clinic in an academic health center. PARTICIPANTS: Forty-two healthy subjects (22 males and 20 females) between the ages of 35 and 65 (mean age 44.2 years) were recruited and completed the study. Subjects received aspirin 325 mg, aspirin 650 mg, and placebo for 4 consecutive days, and on the fourth day also ingested 500 mg of immediate-release niacin 30 minutes after taking aspirin or placebo. They reported the intensity of flushing, headache, pruritus, tingling, and warmth on a 10-cm visual analogue scale. Reactions were evaluated at time 0 (before the niacin dose), and at 15, 30, 60, and 120 minutes following the niacin dose. Cutaneous reactions were compared at each evaluation time and scored by two other methods. The peak intensity was the highest score recorded at any of the four evaluation times after niacin administration. An intensity-time factor was calculated by totaling the scores of each of the four evaluation times. MEASUREMENT AND MAIN RESULTS: The symptom scores for flushing, itching, tingling, and warmth were all significantly reduced by both aspirin regimens (p < .05 in all cases), although there were no significant differences between the 325-mg and 650-mg doses. The results were similar for each scoring method. CONCLUSIONS: An aspirin regimen of 325 mg is effective in suppressing niacin-induced cutaneous reactions. Increasing the dose to 650 mg does not provide additional benefit.

Adult↗

PubMed1995

Probable propafenone-induced transient global amnesia.

OBJECTIVE: To describe a probable case of transient global amnesia caused by propafenone. This adverse effect has not been previously described for this agent. CASE SUMMARY: A 61-year old man with a history of sick sinus syndrome with persistent atrial fibrillation and infrequent premature ventricular contractions was admitted to the hospital for symptoms of amnesia and disorientation to time, place, and date. He began taking propafenone only 6 days prior to admission because of uncontrolled atrial fibrillation and symptoms of fatigue. His atrial fibrillation subsequently had converted to normal sinus rhythm while he received propafenone without adverse effects prior to this episode. His symptoms of amnesia resolved approximately 6-7 hours after discontinuing the propafenone therapy. DISCUSSION: Propafenone is a class 1C antiarrhythmic agent that blocks fast sodium channels in heart muscle and Purkinje fibers similar to the action of encainide and flecainide. It also produces weak beta- and calcium-channel blockade. It has a significant adverse effect profile, with 30-45% of patients reporting cardiac adverse effects and 15-20% experiencing noncardiac events. Central nervous system effects that parallel amnesia have been reported in 10-15% of the patients, including dizziness, ataxia, drowsiness, fatigue, confusion, and paranoia. Propafenone's distribution, clearance, and structural similarity to propranolol contribute to its central nervous system effects. CONCLUSIONS: The rapid resolution of this patient's symptoms after discontinuing propafenone therapy and the absence of recurrence lend credence to the probability of this effect. Comparable adverse effects, such as disorientation and temporary amnesia, have been reported in patients in the analogous agent, propranolol. Consequently, this is a likely, although rare, possible adverse effect with propafenone for which patients should be monitored.

Amnesia↗