Loperamide

May cause drowsiness or dizziness, which may impair physical abilities to operate heavy machinery or tasks requiring mental alertness

Hypersensitivity reactions reported, including anaphylaxis, rash, urticaria, and rare cases of Steven’s Johnson syndrome or toxic epidermal necrolysis

Discontinue if no improvement seen within 48 hours in patients with acute diarrhea, symptoms worsen, or abdominal swelling or bulging develops

Discontinue promptly if constipation, abdominal pain or distention, blood in stool, or ileus develops; do not use when peristalsis inhibition should be avoided (ie, due to potential for ileus, megacolon, or toxic megacolon)

Discontinue therapy if symptoms of abdominal distention occur in patients with AIDS; cases of toxic megacolon reported with infectious colitis, resulting from viral or bacterial pathogens

Use with caution in patients with hepatic impairment due to reduced first pass metabolism; monitor for signs of CNS toxicity

Use of higher than recommended doses or abuse of loperamide can result in serious cardiac adverse events, including QT interval prolongation, Torsades de Pointes, or other ventricular arrhythmias, syncope, and cardiac arrest; in cases of abuse, individuals often use other drugs together with loperamide in attempts to increase its absorption and penetration across the blood-brain barrier, inhibit loperamide metabolism, and enhance its euphoric effects

Dehydration, particularly in pediatric patients less than 6 years of age, may further influence variability of response to loperamide

Avoid loperamide in combination with drugs or herbal products known to prolong QT interval, including Class 1A (e.g., quinidine, procainamide) or Class III (e.g., amiodarone, sotalol) antiarrhythmics, antipsychotics (e.g., chlorpromazine, haloperidol, thioridazine, ziprasidone), antibiotics (e.g., moxifloxacin), or any other drug known to prolong the QT interval (e.g., pentamidine, methadone)