A 'Pill in the Pocket' for POTS patients
Channel: York Cardiology
Date: 2019-03-12

One of the subjects I have become very interested in POTS. For those who don’t know POTS, it stands for postural orthostatic tachycardia syndrome and is characterised by an excessive increase in heart rate when the patient is upright and this can be extremely unsettling. The heart races, the patients feels tremulous and can feel very dizzy. In addition, patients with POTS have many other symptoms which are not postural. These include always feeling tired, never waking up feeling refreshed, very unpredictable and prolonged brain fog, gut issues such as swallowing difficulties, bloating, and constipation or diarrhoea and temperature issues such as feeling excessively cold at time and excessively hot at other times. Such patients often also have joint hypermobility, irritable bowel syndrome, fibromyalgia, chronic fatigue syndrome and migraines. Treatment is difficult but usually involves increasing blood volume by increasing fluid intake and salt intake. One of the biggest problems for POTS patients is that the symptoms can be unpredictable and this means that patients struggle to look forward to anything because they don’t know how they will feel on a specific day and this can sometimes lead them to avoid important events and this can lead to worsening social isolation which then makes everything worse.

Today I wanted to discuss an interesting medication that can be used as a ‘pill in the pocket’ in those situations where the patient may be worried that their symptoms may flare up.

The medication is called Desmopressin or sometimes also called DDAVP. It is used as tablet although you can also use it as a nasal spray (Desmospray). DDAVP is a synthetic version of arginine vasopression which is a natural anti-diuretic which means that it helps retain more water in the body by reducing the amount of water that is passed out in the urine. 

In an interesting study published in Heart rhythm journal in 2012, Samuel Coffin et al found that when they gave 30 patients a 0.2 mg tablet of DDAVP and compared to placebo, there was a significant reduction in the heart rate on standing within 1 hour of taking the medication and this effect persisted for 4 hours. In addition, patiens felt better, complained of less symptoms of racing heart beat and less visual disturbance and tremulousness. 

Subsequently there was a retrospective study which also showed that about half of the patients who were able to tolerate this medication noted improvement in their standing heart rates and symptoms at one year

There are a few things woth knowing about this medication. Because it retains fluid and because patients with POTS are told to drink a lot anyway, the extra water can cause a drop in sodium levels in the body and this can be dangerous. Secondly the fluid retention can cause oedema or sometimes headaches.  Because of this risk of the sodium levels falling low, doctors who treat POTS generally recommend a close watch on blood  levels and also recommend that rather than this medication be taken daily, it should be used as a pill in the pocket.

I think as a pill in the pocket, it may offer a lot of hope to patients with POTS as this may allow them to get some quality of life back.