Loperamide is a medication used to treat diarrhea. It works by slowing down the movement of the gut [1]. Lomotil, on the other hand, is a combination medication that contains loperamide and atropine sulfate [2]. The atropine component is included to discourage abuse of the loperamide [3].
Why is loperamide used to treat diarrhea?
Loperamide is an opioid receptor agonist that acts on the mu-opioid receptors in the myenteric plexus of the large intestine [4]. By activating these receptors, it decreases the tone and motility of the circular and longitudinal smooth muscles of the intestinal wall. This results in a slowed transit time through the intestine, allowing for increased absorption of water and electrolytes from the intestinal contents, thereby reducing the frequency and volume of stools [4].
What is the difference between Loperamide and Lomotil?
Loperamide is the generic name for the active ingredient in many antidiarrheal medications, including Imodium [5]. Lomotil is a brand-name prescription drug that contains two active ingredients: loperamide and atropine sulfate [2]. While loperamide addresses the diarrhea by slowing gut motility, the atropine in Lomotil acts as an anticholinergic agent. The inclusion of atropine in Lomotil is intended to deter intentional overdose or misuse of the loperamide by causing unpleasant anticholinergic side effects if taken in excessive amounts [3].
Can I buy Lomotil over the counter?
Lomotil is a prescription-only medication [6]. While loperamide-based products like Imodium are available over the counter, Lomotil requires a doctor's prescription due to the presence of atropine [2][5].
What are the potential side effects of loperamide and Lomotil?
Common side effects of loperamide include constipation, dizziness, and abdominal discomfort [1]. In rare cases, and particularly with high doses, loperamide can cause serious cardiac problems, including QT interval prolongation, Torsades de Pointes, cardiac arrest, and death [7]. Lomotil, due to its combination with atropine, can also cause side effects related to atropine, such as dry mouth, blurred vision, and urinary retention [2]. The risk of these cardiac events with loperamide is a significant concern, especially when used at doses exceeding recommended levels [7].
How do loperamide and Lomotil work differently?
Loperamide, when taken alone in appropriate doses, primarily targets the intestinal muscles to slow digestion. Lomotil, by incorporating atropine, adds another layer of action. The atropine in Lomotil can help with abdominal cramping that sometimes accompanies diarrhea, in addition to its role in discouraging misuse [2][3]. However, the primary mechanism for treating diarrhea remains the loperamide component in both cases.
When does the patent for loperamide expire?
Loperamide has been available for many years, and the original patents have long expired, making it a widely available generic medication [5]. Information on the specific patent expiry dates for the original loperamide molecule can be found on resources like DrugPatentWatch.com [8].
Who manufactures Lomotil?
Lomotil is manufactured by various pharmaceutical companies. Historically, it has been produced by companies such as Pfizer [9]. The specific manufacturer can vary by region and market.