are formulated with other ingredients (acetaminophen, antihistamines, and sympathomimetics) that can be fatal in overdose. Loperamide is sometimes used in large doses to create an opioid-like high or to self-treat opioid withdrawal symptoms. In large doses, loperamide may cross the blood-brain barrier and cause altered mental status and respiratory depression; additionally, loperamide may induce ventricular arrhythmias in supratherapeutic doses. Pseudoephedrine, a decongestant contained in numerous OTC cold preparations, has been used in the illicit manufacture of methamphetamine. A general awareness of these products and their formulations will enable clinicians to more fully appreciate the potential for OTC medication-related problems in their patients.
Table 63–2 lists examples of OTC products that may be used effectively to treat common medical problems. The selection of one ingredient over another may be important in patients with certain medical conditions or in patients taking other medications. These are discussed in detail in other chapters.
TABLE 63–2 Ingredients of known efficacy for selected over-the-counter (OTC) classes.
Ranitidine (Zantac 75, Zantac 150)
Fexofenadine (Allegra 12 hour, Allegra 24 hour)
Loratadine (Alavert, Claritin) Relief and prevention of heartburn associated with acid indigestion.
Treatment of frequent heartburn (occurs 2 or more days a week).
Temporary relief of the following symptoms due to hay fever or upper respiratory allergies: sneezing, runny nose, itchy, watery eyes, itching of nose or throat.
Avoid use: in children <12 years of age; if patient has trouble or pain swallowing food, vomiting with blood, or bloody or black stools; with other acid reducers; if symptoms include heartburn with lightheadedness, sweating, dizziness, or chest pain; for treatment durations >14 days.
Adverse effects include: nausea, agitation, headache, dizziness, agitation, and gynecomastia (cimetidine; rare).
Avoid use: in children <18 years of age; if patient has trouble or pain swallowing food, vomiting with blood, or bloody or black stools; if symptoms include heartburn with lightheadedness, sweating, dizziness, or chest pain; for treatment durations >14 days.
Adverse effects include: headache, abdominal pain, nausea, diarrhea, and flatulence.
Avoid use: in children <2 years of age; in combination with other sedatives and alcohol as sedative effects may be potentiated. Use caution when driving or operating machinery.
Adverse effects include: drowsiness, dizziness, fatigue, nausea, and urinary retention.
Antihistamines are contained in many OTC preparations in combination with analgesics, decongestants, and expectorants. See the warnings section for each formulation.
To prevent symptoms, take 30–60 minutes before consuming food or beverages that cause heartburn.
Cimetidine may increase the serum concentrations of theophylline, warfarin, and phenytoin.
Not intended for immediate relief (products take 1–4 days for full effect).
Take with water before eating in the morning.
Patients may repeat a 2-week course of therapy every 4 months.
PPI therapy can increase risk of Clostridium difficile-associated diarrhea and risk of fracture.
Esomeprazole, lansoprazole, and omeprazole may interact with warfarin, clopidogrel, cilostazol, antifungal medications, diazepam, digoxin, tacrolimus, and HIV antiretrovirals.
Diphenhydramine is the most sedating antihistamine.
Consult product labeling before use in children ages 2–11 years.