A non-constipating diarrhoea treatment
Racecadotril’s arrival on the UK market has been more of a silent disco. The drug is licensed for treating acute diarrhoea, pitting it against loperamide. It is licensed for use in anyone over three-months old.
Who it is for
When new products come out, they are often accompanied by a fanfare, drug representatives do the rounds and advertisements appear in journals. Racecadotril’s arrival on the UK market has been more of a silent disco. The drug is licensed for treating acute diarrhoea, pitting it against loperamide. It is licensed for use in anyone over three-months old.
- Racecadotril (Hidrasec) is licensed to treat acute diarrhoea for up to seven days. It can be used for children from three months old.
- It decreases interstitial secretion of water and electrolytes but does not modify interstitial transit — constipation is unlikely.
- Oral rehydration is still recommended — the product’s licence for children requires use together with oral rehydration.
How it works
“Racecadotril [Hidrasec] is relatively new to the UK market but has been available in other countries for several years,” says Larry Goodyer, head of the school of pharmacy at De Montfort University and deputy chairman of the British Global and Travel Health Association. “It has an interesting mode of action being an enkephalinase inhibitor and, therefore, prolongs the action of endogenous enkephalin the gastrointestinal tract. Since enkephalin has strong antihypersecretory activity, the drug can reduce fluid loss and alleviate the symptoms of diarrhoea without having an effect on gut muscle. This is in contrast to other common antidiarrhoeal agents, such as loperamide, which have antimotility properties.”
Several studies have compared racecadotril with loperamide. One group of researchers, in a comprehensive review of the pharmacodynamics, pharmacokinetics and clinical effects of racecadotril, summarised these (Frontiers in Pharmacology 2012;3:93). They concluded: “Racecadotril was at least as effective as loperamide and, in several of those studies, exhibited significantly better tolerability than loperamide. Most notably, rebound constipation was consistently less frequent with racecadotril than with loperamide.” Professor Goodyer notes that racecadotril appears to be more effective at improving abdominal discomfort.
Hidrasec is available as capsules (100mg) and granules for oral suspension. After the first dose, which can be taken any time, racecadotril is taken by adults at a dose of 100mg tds, preferably before each meal. For children, dosing is weight based as follows:
- Less than 9kg — one 10mg sachet tds
- 9–13kg — two 10mg sachets tds
- 13–27kg — one 30mg sachet tds
- Above 27kg — two 30mg sachets tds
The apricot-flavoured granules, which contain sugar, can be added to food or should be mixed with water and given immediately.
Treatment continues until two normal stools are produced. The maximum licensed duration of use is seven days.
Despite its mechanism of action, oral rehydration solutions are still recommended and usual dietary measures should be applied. In fact, the product’s licence for children requires use together with rehydration.
According to the summary of product characteristics for racecadotril, the only common side effect with treatment, after exposure to over 2,000 adults and 800 children, is headache. Rash and erythema are listed as uncommon.
Racecadotril costs £7.39 (excluding VAT) per 20-unit pack — the cost is the same for the capsules and both strengths of sachet.
By comparison, according to the Drug Tariff (accessed in April 2013), loperamide costs:
- £1.07 for 30 x 2mg capsules
- £5.02 for 18 x 2mg oral lyophilisates
- £1.17 for 100ml of the 1mg/5ml liquid
Place in therapy
“Racecadotril doesn’t cause constipation,” Professor Goodyer highlights. “In this respect, it could be particularly useful for elderly patients. It may also prove useful for children aged between three months and five years, since loperamide is not indicated for acute diarrhoea in this age group.” That said, the National Institute for Health and Care Excellence guideline for treating diarrhoea in children under five years does not recommend the use of antidiarrhoeals, although it was written before racecadotril reached Britain.
“A potential, but largely untested, area might be in the management of traveller’s diarrhoea,” Professor Goodyer says. “A recent review in the Drug and Therapeutic Bulletin pointed out that the evidence base supporting the claims for racecadotril was not strong and it did not improve major clinical outcomes. Although acute diarrhoea is often a self-limiting condition symptoms can be distressing and inconvenient, so an alternative to loperamide, particularly in children, may be of benefit. For this reason it might be useful if racecadotril could, in time, be available as an over-the-counter product.”
Racecadotril is not recommended by the Scottish Medicines Consortium. One might presume that this is down to a lack of efficacy but the SMC says that it is because the manufacturer did not present a sufficiently robust analysis to gain acceptance. The All Wales Medicines Strategy Group has also rejected use. NICE has produced evidence summaries for racecadotril in both adults (ESNM11) and children (ESNM12).
At first glance, the market for racecadotril seems small. However, some see another theoretical potential in its arrival. One of those is Sinead Holmes, a pharmacist specialising in colorectal surgery at Wirral University Teaching Hospital, who sees many patients with stomas. “High-dose loperamide (16–64mg/day) is currently used for patients with stomas for its antimotility effect to reduce stoma output,” she explains. “This has beneficial effects on fluid and electrolyte balance, as well as nutrition. Typically, loperamide is combined with a high-dose proton pump inhibitor for its antisecretory effects… . In theory, racecadotril could be a useful option for patients with stomas because it has antidiarrhoeal and antisecretory effects. However, due to its lack of effect on gastric motility, it would be limited to adjunctive therapy.”
There is a lack of trials of racecadotril in patients with stomas. All phase III clinical trials have involved short-term treatment, and, as Mrs Holmes points out, “it is likely that future use of racecadotril will either be embraced or discounted through anecdotal evidence”. She adds: “Given that the drug is not systemically absorbed, the theoretical likelihood of long-term complications is small. However, only time will tell.”
Citation: The Pharmaceutical Journal DOI: 10.1211/PJ.2013.11122233
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