Rehydril100 mg

Rehydril 100 mg is an intestinal antisecretory agent used for the symptomatic treatment of acute diarrhoea in adults and children (from 3 months of age), used as an adjunct to, and never as a replacement for, appropriate oral rehydration therapy.

Important limitations of use: Rehydril 100 mg is not effective for and should not be used in chronic diarrhoea, antibiotic-associated diarrhoea, or diarrhoea accompanied by fever and/or bloody or purulent stools, since these may indicate an invasive bacterial infection or another serious underlying condition requiring different management.

Contains Rehydril 100 mg as the active ingredient, available as oral capsules (commonly 100 mg for adults) and granules/powder for oral suspension (commonly 10 mg and 30 mg sachets for infants and children).

Rehydril 100 mg is an antidiarrheal medicine that works differently from typical antimotility agents like loperamide - rather than slowing gut movement, it reduces the excessive secretion of water and electrolytes into the intestine that occurs during acute diarrhoea, without affecting normal intestinal transit time. This mechanism allows it to reduce stool output and shorten the duration of acute diarrhoea while producing constipation less often than motility-slowing antidiarrheal agents. It is intended for short-term use (up to 7 days) alongside oral rehydration therapy, which remains the essential foundation of acute diarrhoea management, particularly in young children.

Therapeutic Class: Antidiarrheal (Intestinal Antisecretory Agent)

Rehydril 100 mg is rapidly and extensively metabolized after oral administration into its active metabolite, thiorphan, which inhibits enkephalinase, an enzyme in the intestinal wall that normally breaks down the body's own protective enkephalins. Rehydril 100 mg acts locally in the small intestine and does not cross the blood-brain barrier in clinically significant amounts, which is why, unlike some other enkephalinase-related agents, it does not produce central nervous system opioid-type effects. It provides an antidiarrheal effect quickly, without altering normal gastrointestinal transit time, and is eliminated via urine, faeces, and the lungs.

• Taken orally, preferably before meals
• Capsules may be swallowed whole with water; granules/sachets should be mixed with water or food (such as a bottle of milk or a meal) immediately before administration in infants and children
• Use together with appropriate oral rehydration solution as directed - Rehydril 100 mg does not replace the need for adequate fluid and electrolyte replacement
• Continue treatment until 2 normal stools have been passed, but do not use for more than 7 days without medical advice

The following should be assessed by a healthcare professional before combining with Rehydril 100 mg:

• ACE inhibitors (such as lisinopril, enalapril, or ramipril): concurrent use may increase the risk of angioedema (sudden swelling of the face, lips, tongue, or throat); use with caution and be alert for symptoms.
• Other antidiarrheal medicines (such as loperamide): using multiple antidiarrheal medicines together is generally not recommended unless specifically directed by a healthcare professional.

Joint treatment with Rehydril 100 mg and loperamide or nifuroxazide has not been shown to alter Rehydril 100 mg's own pharmacokinetics, but combining antidiarrheal agents should still only be done on medical advice.

Common side effects

• Headache
• Skin reactions, including rash

Less common but serious effects (seek medical attention)

• Angioedema: swelling of the deeper layers of the skin, typically around the eyes and lips - seek urgent medical attention if this occurs
• Erythema multiforme: a rare but serious skin reaction with red patches or blisters
• Urticaria (hives)

Overall, adverse events with Rehydril 100 mg are generally not significantly different in frequency from placebo in clinical trials, both in adults and children.

Pregnancy

Due to a lack of sufficient clinical data, Rehydril 100 mg should not be administered to pregnant women unless a doctor determines it is clearly necessary.

Breastfeeding

Due to a lack of sufficient clinical data, Rehydril 100 mg should not be administered to breastfeeding women unless a doctor determines it is clearly necessary.

• Not a substitute for rehydration: oral rehydration solution remains the cornerstone of acute diarrhoea management, particularly in infants and young children, and must be continued alongside Rehydril 100 mg, not replaced by it.
• Not for chronic or antibiotic-associated diarrhoea: Rehydril 100 mg has not been adequately studied for these situations and should not be used.
• Bloody or purulent stools, or diarrhoea with fever: may indicate invasive bacterial infection or another serious condition; Rehydril 100 mg is not appropriate for this presentation, and medical evaluation is needed instead.
• Use with caution in patients with renal or hepatic impairment, given limited clinical data in these populations.
• Not recommended for infants under 3 months of age, given a lack of clinical studies in this age group.
• Do not use for more than 7 days without consulting a doctor.

Acute overdose of Rehydril 100 mg may cause sedation, nausea, and headache. There is no specific antidote; treatment is generally supportive, with a focus on maintaining adequate hydration and monitoring electrolyte levels, provided by a healthcare professional if a significant overdose is suspected.

Store at room temperature, between 15°C and 25°C, away from moisture and heat, as directed on the product label.

• Infants under 3 months: Not recommended, given a lack of clinical studies establishing safety and dosing in this age group.
• Infants and children 3 months and older: Weight-based dosing using age-appropriate granule sachets, as shown in the dosage table.
• Renal or hepatic impairment: Use with caution, given limited clinical data in these populations.

Rehydril 100 mg is used for short-term, symptomatic treatment of acute diarrhoea, continued until 2 normal stools have been passed, and should not be used for more than 7 days without consulting a doctor, given a lack of data supporting longer use.

Drug Class: Enkephalinase inhibitor (Rehydril 100 mg, converted to its active metabolite thiorphan)

Rehydril 100 mg inhibits enkephalinase, an enzyme that normally breaks down the body's own naturally occurring enkephalins in the gut wall. By protecting these enkephalins from breakdown, Rehydril 100 mg prolongs their protective action, which reduces the excessive secretion of water and electrolytes into the intestinal lumen that drives acute diarrhoea (such as that caused by cholera toxin or intestinal inflammation), without slowing down normal gut motility the way typical antimotility antidiarrheal agents do.

Rehydril 100 mg is used in infants and children from 3 months of age, with weight-based dosing using age-appropriate granule sachets (10 mg, 20 mg, or 30 mg depending on weight), always alongside appropriate oral rehydration solution. It is not recommended in infants under 3 months, given a lack of clinical data in this age group.