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Frequently Asked Questions


Below please find relevant questions and answers divided into the following five categories.

Mode of Action


Side effects



Mode of Action

Q: How long does DesmoMelt take to work?

A: Following sublingual administration of DesmoMelt the maximum plasma levels are seen approximately 0.5 - 2 hours after administration. Most patients respond immediately to DesmoMelt. The starting dose for DesmoMelt is one 120mcg Melt at bedtime. If the effect at this lowest dose is insufficient then the dose may be raised to 2 x 120mcg or 1 x 240mcg Melt at bedtime.

Q: Do DesmoMelts have any direct effect on the bladder?

A: There is no known direct effect on the smooth muscle of the bladder.

Q: Do DesmoMelts affect blood pressure?

A: Desmopressin has no direct effect on blood pressure. Desmopressin is highly specific for the V2 receptor. Compared with vasopressin it has a pressor activity of less than 0.001%.

Q: For how long will desmopressin DesmoMelt remain in the body?

A: With a half life-time of approximately 2-3 hours, the expected pharmacological duration of action of approximately 8 hours.

Q: What is the optimal treatment duration with DesmoMelt to achieve complete dryness?

A: It is not possible to recommend an optimal duration of treatment since some patients may become dry after the first three months of treatment, whereas others will require longer therapy. A patient can be treated for as long as the symptoms persist. The need for continued treatment should be assessed every three months by withholding treatment for at least a week. If the patient wets during that time then DesmoMelt treatment can recommence at the last successful dose.

Q: Can DesmoMelt be taken with meals?

A: The absorption of desmopressin from the gastrointestinal tract has been shown to be reduced and delayed if the drug is administered together with food. However there seems to be only limited clinical relevance to this.

Q: Can fluid retention occur during DesmoMelt treatment without excessive fluid intake?

A: Desmopressin does not create water. Water ingestion is the primary pathogenic mechanism in water intoxication, i.e. regardless of the presence of desmopressin, fluid intake must exceed loss of water for an increase of body water to occur. It is important to stress that patients on DesmoMelt treatment must limit their fluid intake from one hour before until at least eight hours after taking a dose. It is important to assess drinking habits prior to initiating treatment with DesmoMelt to exclude polydipsia or other conditions causing fluid or electrolyte imbalance. DesmoMelt should also be discontinued during an episode of vomiting and / or diarrhoea until fluid balance is once again normal.

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Q: What is the dosage of DesmoMelt in PNE?

A: The dosage is 1 x 120mcg DesmoMelt increasing to 2 x 120mcg or 1 x 240mcg DesmoMelt only if necessary.

Q: At what age can you start using DesmoMelt for Primary Nocturnal Enuresis?

A: DesmoMelt is licensed for treatment of primary nocturnal enuresis (PNE) in patients aged 5 to 65 years.

Q: For how long can DesmoMelt be used?

A: Clinical studies indicate that desmopressin can be used long-term. A patient can be treated for as long as the symptoms persist - for many years if required. The need for continued treatment should be assessed every three months by witholding treatment for at least a week. If the patient wets during that time then DesmoMelt treatment can recommence at the last successful dose.

Q: Are there any negative effects after long term treatment with desmopressin?

A: Based on the results in our post-marketing safety database and long-term studies, there appear to be no specific long term side effects. Long term safety is also supported by the fact that patients with diabetes insipidus are treated with desmopressin for many years.

Q: Is there any difference between doses for adults and children?

A: There does not seem to be evidence of increased dosage needs in adults compared to children. At any age group patients doses appear to be individual.

Q: What is the maximum dose?

A: The maximum recommended dosage of DesmoMelt for Primary Nocturnal Enuresis is 240mcg at bedtime.

Q: What happens if a patient overdoses?

A: Desmopressin in itself does not create a risk by overdosing. For high dosages of desmopressin an increased duration of action can be expected with a subsequent risk of fluid retention which, in turn, can lead to hyponatraemia. If overdosing should occur, desmopressin treatment should be immediately stopped and fluid intake restricted until serum sodium is normalised.

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Q: Which drugs should not be taken in combination with DesmoMelt?

A: Substances which are known to induce SIADH eg, tricyclic antidepressants, selective serotonin re-uptake inhibitors, chlorpromazine and carbamazepine, may cause an additive antidiuretic effect leading to an increased risk of water rentetion and/ or hyponatraemia. NSAIDs may induce water retention and/or hyponatraemia. Concomitant treatment with loperamide may result in a 3-fold increase of desmopressin plasma concentrations, which may lead to an increased risk of water retention and / or hyponatraemia. Although not investigated, other drugs slowing transport might have the same effect. If you have any queries or specific interactions please contact the Medical Information department:

Q: Can you give DesmoMelt together with anticholinergics such as oxybutynin?

A: Formal interaction studies have not been performed on this combination so far. However, good clinical results are reported in patients characterised as not responding to desmopressin as monotherapy.

Q: Can DesmoMelt be used in patients with asthma and PNE?

A: There are no specific reasons why a patient with asthma cannot be treated with DesmoMelt for PNE provided they fulfil all the other conditions outlined in the Summary of Product Characteristics

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Side effects

Q: Are there any side effects?

A: Side-effects include headache, stomach pain and nausea. Isolated cases of allergic skin reactions and more severe general allergic reactions have been reported. Very rare cases of emotional disturbances in children have been reported. Treatment with desmopressin without concomitant reduction of fluid intake may lead to water retention/hyponatraemia with accompanying symptoms of headache, nausea, vomiting, weight gain, decreased serum sodium and in serious cases, convulsions. Hyponatremia is a very rare side effect and has mainly been reported to have been associated with excess fluid intake. If a patient reports any suspected side effects with desmopressin please contact the Medical Information Department at Information about adverse event reporting can be found at Adverse events should also be reported to Ferring Pharmaceuticals Ltd.: Medical Information, Ferring Pharmaceuticals Ltd., Drayton Hall, Church Road, West Drayton, UB7 7PS, United Kingdom. Email:

Q: Does Desmopressin affect endogenous hormones?

A: Desmopressin have not been shown to impair the body's ability to produce vasopressin or affect circulating levels of other hormones.

Q: Does Desmopressin have any effect on electrolytes?

A: Desmopressin exerts its main effect in the distal tubule in the kidney where it reabsorbs water. Excessive water re-absorption might result in drops in serum electrolyte concentrations by dilution.

Q: If a patient complains of a headache, should the medication be stopped?

A: A recent review showed 2% of patients report headaches while on desmopressin (1). They tend to be mild and self limiting in nature. However if a patient complains of a severe or prolonged headache this can be one of the signs of hyponatraemia. Treatment should be stopped, fluid restricted and the patient should speak with their Doctor or should visit their hospital for further assistance. A mention of this is made on the Patient Information Leaflet for DesmoMelt.

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Q: What is the recommended fluid intake over a day?

A: We do not give a recommended fluid intake over 24 hours as each person had his or her own "normal" intake. What we would recommend is sensible drinking during the day. The patient should restrict fluid from 1 hour before taking the Melt at bedtime until the next morning and in any case for a minimum of 8 hours after a dose of DesmoMelt. Desmopressin should not be used to treat bedwetting in patients with an unusually high fluid intake. It is important to assess drinking habits prior to initiating treatment with DesmoMelt to exclude Polydipsia or other conditions causing fluid or electrolyte imbalance.

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Q: Where is the gelatin excipient in DesmoMelt sourced from?

A: The gelatin in DesmoMelt is derived from fish skins. The quality standard of the gelatin is according to the pharmacopoeia standards Ph.Eur., USP and JP. There is 12.5mg of gelatin in each DesmoMelt.

Q: Is DesmoMelt suitable for vegans?

A: No the gelatin excipient in the Melt is derived from fish skins.

Q: Is DesmoMelt suitable for vegetarians?

A: No the gelatin in the Melt is derived from fish skins. However, there are some vegetarians who still eat fish, so DesmoMelt would be suitable for these particular patients.

Q: Is DesmoMelt suitable for lactose intolerant patients?

A: Yes – unlike Desmotabs 0.2mg (desmopressin acetate), the Melts do not contain lactose and are therefore suitable for patients with lactose intolerance.

Q: Can DesmoMelt be halved for lower doses?

A: Ferring do not recommend trying to half the Melts to give a smaller dose of desmopressin. The Melts are not scored and they cannot be broken in half accurately.

Q: Is the Summary of Product Characteristics (SmPC) for DesmoMelt available on the eMC (electronic Medicines Compendium) website?

A: Yes – the SmPC for DesmoMelt is available on the eMC website. The spelling of DesmoMelt must be all one word, otherwise it will not be found on the eMC website. An easier way may be to put the active ingredient ‘desmopressin’ as a search term – this will bring up all available forms of desmopressin, including the Melts.

Q: DesmoMelt is supposed to be administered sublingually (under the tongue) – would there be any problems in placing the Melt on the tongue instead?

A: The licensed means of administration is sublingual. In all of the clinical trials conducted thus far the Melt was administered sublingually. We advise the use of the product sublingually.

Q: What are the excipients of DesmoMelt?

A: Each Melt contains gelatin, mannitol and citric acid.

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1. PEV van Kerrebroeck - Experience with the long-term use of desmopressin for nocturnal enuresis in children and adolescents, BJU International (2002), 89, 420-425