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Posted by on May 11, 2013 in The Treatments |

Histamine Blockade

Histamine Blockade

Do you want to know more about H1-H2 blockers? Head for the forums in The Pharmacy to discuss!

When mast cells degranulate, either spontaneously (for no reason whatsoever) or due to a particular trigger, hundreds of chemical agents are released into the body. One of these chemicals is Histamine. If you are a mastocytosis patient, you will often experience elevated levels of histamine in your tissues as you have an overabundance of trigger-happy mast-cells.

Increased histamine causes irritation and inflammation in various parts of the body. The most common places histamine causes a reaction is in the skin, the nasal passages and the bronchial tubes. It also causes excess stomach acid to be produced, thereby causing heartburn.

In mastocytosis patients, the effect of histamine can be devastating and could even be lethal in some instances.

In order to contain the effects of histamine release, H1 receptor blockers are used to stem the impact of histamine on airways, lungs, nose and mouth. H2 receptor blockers are used to control the amount of stomach acid produced.

How Do H1 Blockers Work?

Watch this 1:21 min snippet to find out.

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How Do H2 Blockers Work?

H2 blockers, which are also called H2-receptor antagonists, are medicines used to reduce the amount of acid the stomach produces. H2 blockers work by blocking the histamine receptors in acid producing cells in the stomach. Parietal cells are cells that are the source of the hydrochloric acid (gastric acid) and most of the water in the stomach's digestive juices. These cells produce hydrochloric acid in response to a combination of three things: histamine (via H2 receptors), gastrin (via gastrin receptors), and acetylcholine (via M3 receptors). H2 blockers can be used to treat acid reflux by blocking the effects of histamine on parietal cells.

Watch this short 7 sec. clip to see the acid producing (parietal) cells and the 3 receptors mentioned above, one of which is the H2 receptor on which histamine binds.

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H2 blockers are used for the treatment of symptoms of gastroesophageal reflux disease, and also for the treatment of diseases like peptic ulcers, gastritis, and esophagitis. H2 blockers act very quickly (the effects are seen after 1 hr) but the do not last very long (about 12 hours).

The H2 blockers that are available are similar in how they work. They can be different in how they interact with other medications you are taking. For this reason you should talk to your doctor about which H2 blocker you can take based on what other medication you are taking. Here are some typical brand names of H2 blockers:

  • Prescription
    • Tagamet (cimetideine)
    • Pepcid (famotidine)
    • Axid (nizatidine)
  • Over-the-counter
    • Tagamet-HB
    • Pepcid-AC
    • Axid AR

There is recent evidence that  prolonged use increases the risk of hip fractures by 18% in individuals already at risk due to other conditions. It does not increase the risk of hip fractures if you do not have an elevated risk already.  (Proton Pump Inhibitors and Histamine-2 Receptor Antagonists Are Associated With Hip Fractures Among At-Risk Patients) so try and be on the lowest effective dose if possible, due to altered calcium absorption.

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Posted by on May 11, 2013 in The Treatments |

Proton Pump Inhibitors

Proton Pump Inhibitors

This post is still under construction.

Disregard its content, if any, as it only contains raw reference material for the future post.

Questions about PPIs? Head for the forum

Watch this 17 sec. video to get the gist of PPI's

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Controlling acid production

Imagine you're watering your little patch of grass you call your garden  using a water hose.  But you have been at it for a while now, and, if you carry on with the hose, you're going to turn your garden into a swimming pool. What are the 2 most effective ways to stop the water?

You can cut off the water supply at the the tap (stopping water production) or you can cut off the water supply at the nozzle (stopping water egress).

Both actions have the same effect, but the way the effect is achieved is different.

The same is true with cutting off acid supply into the stomach. You can block the cells which produce the acid. Or you can let the cells produce acd, but block the flow of the acid into the stomach.

Preventing the production of acid is done through h2 blockers.  Preventing produced acid from flowing into the stomach is done through Proton pump inhibitors.

In the video above,

 

Slow, long term
delayed onset a couple of hours
can relieve symptoms for up to 3 days
Omeprazole (prilosec)
Lansoprazole (Prvacid)
Rabeprazole (Aciphex)
Pantoprazole (Protonix)
Esomepraxole (nexium)
Zegarid (rapid release of omeprazole
diarrhea, Nausea, Headache, abdominal pain
Ulcers, GERD, Esophagitis
H2 Blockers
Sore throat, diarrhea, Nausea, Headache, Weakness

There is evidence that prolongued use causes hip fractures of 18% for H2 30% PPI
Mild Heartburn, try and be on the lowest effective dose due to altered calcium absorption
Proton Pump Inhibitors and Histamine-2 Receptor Antagonists Are Associated With Hip Fractures Among At-Risk Patients http://www.gastrojournal.org/article/S0016-5085(10)00488-9/abstract

PPI Some agents in this group include: Omeprazole (Losec, Prilosec, Zegerid, ocid); Lansoprazole (Prevacid, Zoton, Inhibitol); Esomeprazole (Nexium); Pantoprazole ( Protonix, Somac, Pantoloc, Pantozol, Zurcal, Pan); Rabeprazole ( Rabecid, Aciphex, Pariet, Rabeloc)

The proton pump is the terminal stage in gastric acid secretion, being directly responsible for secreting H+ ions into the gastric lumen, making it an ideal target for inhibiting acid secretion. (“Irreversibility” refers to the effect on a single copy of the enzyme; the effect on the overall human digestive system is reversible, as the enzymes are naturally destroyed and replaced with new copies.)

Targeting the terminal-step in acid production, as well as the irreversible nature of the inhibition, result in a class of drugs that are significantly more effective than H2 antagonists and reduce gastric acid secretion by up to 99%.

PPIs include:
Aciphex (raberprazole)
Dexilant (dexlansoprazole)
Nexium (esomeprazole)
Prevacid (lansoprazole)
Prilosec (omeprazole)
Protonix (pantoprazole)

How are PPIs different from H2 Blockers?

Both PPIs and H2 Blockers suppress gastric acid secretion. They are different, however, in how they do this. While PPIs shut down the proton pumps in the stomach, H2 Blockers work by blocking the histamine receptors in acid producing cells in the stomach.
PPIs have a delayed onset of action, while H2 blockers begin working within an hour. PPIs work for a longer period of time; most up to 24 hours and the effects may last up to three days. H2 Blockers, however, usually only work up to 12 hours.

Question: What Are H2 Blockers?
Answer:
Your doctor may also prescribe a Proton Pump Inhibitors (PPIs). There has been some confusion as regards these two medications because some people assume they work the same and are interchangeable. While both PPIs and H2 blockers suppress gastric acid secretion, they work at different stages of production.. While histamine blockers block one of the first stimuli for acid production, proton pump inhibitors block the final step in the pathway of acid secretion in the stomach, resulting in greater suppression of acid. PPIs shut down the proton pumps in the stomach, H2 blockers work by blocking the histamine receptors in acid producing cells in the stomach. PPIs have a delayed onset of action, while H2 Blockers begin working within an hour. PPIs work for a longer period of time; most up to 24 hours and the effects may last up to three days. H2 Blockers, however, usually only work up to 12 hours.

Proton pump inhibitor use, hip fracture, and change in bone mineral density in postmenopausal women: results from the Women’s Health Initiative
Gray SL, LaCroix AZ, Larson J, Robbins J, Cauley JA, Manson JE, Chen Z.
Arch Intern Med. 2010 May 10;170(9):765-71.

Increase in vertebral fracture risk in postmenopausal women using omeprazole
Roux C, Briot K, Gossec L, Kolta S, Blenk T, Felsenberg D, Reid DM, Eastell R, Glüer CC.
Calcif Tissue Int. 2009 Jan;84(1):13-9. Epub 2008 Nov 21.
n an article (Doornebal J, et al. Ned Tijdschr Geneeskd .2009;153; 153:A7110), published in the Netherlands, the authors stated that the long term use of proton pump inhibitors could lead to serious hypomagnesemia.
Long-term proton pump inhibitor therapy and risk of hip fracture
Yang YX, Lewis JD, Epstein S, Metz DC.
JAMA. 2006 Dec 27;296(24):2947-53.
A case series of proton pump inhibitor-induced hypomagnesemia
Hoorn EJ, van der Hoek J, de Man RA, Kuipers EJ, Bolwerk C, Zietse R.
Am J Kidney Dis. 2010 Jul;56(1):112-6. Epub 2010 Feb 26.

Concern About Iron Interference
In a couple of recent articles, the impact that proton pump inhibitors can have on iron status was highlighted. In the first study [Hutchinson, et al: Gut. 56(9):12915], the researchers point out that during long term treatment of hereditary hemachromatosis, they observed that the use of proton pump inhibitors reduced the requirement for maintenance phlebotomy.

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Posted by on May 11, 2013 in The Treatments |

Mast Cell Stabilisers

Mast Cell Stabilisers

This post is still under construction.

Disregard its content, if any, as it only contains raw reference material for the future post.

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Posted by on May 11, 2013 in The Treatments |

Tyrosine-Kinase Inhibitors

Tyrosine-Kinase Inhibitors

This post is still under construction.

Disregard its content, if any, as it only contains raw reference material for the future post.

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Posted by on May 10, 2013 in The Treatments |

Adrenaline Auto-injector

Adrenaline Auto-injector

Did you use your EpiPen? Was it successful? Did you need more than one? What was your experience? Please share with us in The Hospital Room  forum.

Because there is an increased risk that you may experience an anaphylactic shock (also called anaphylaxis) if you suffer a massive degranulation, you will need to take some precautions to be able to handle such an event. You will need to carry with you a self-injectable dose of epinephrine at all times. This dose is contained in a syringe called an EpiPen. That may sound a bit sinister, but it shouldn't be that big a deal. It just means you will have to get into the habit of reaching for your EpiPen as you reach for your door keys and not to leave home without it.

Once you have been diagnosed with Mastocytosis,  your doctor will prescribe either one or two EpiPens. An EpiPen is essentially a very sturdy syringe that contains a shot of 0.3 ml of epinephrine. Because of the protective sheath and delivery mechanism around the syringe, you will need to familiarise yourself with the instructions to administer the shot should you need it. Your doctor or your nurse will spend 10-20 minutes with you to teach you how to do this safely and answer any queries you may have.  Again, there is nothing to worry about, it is a very simple procedure once you know how to do it. However, you must inject yourself using the correct procedure.

It is a good idea to take a family member or a close friend with you when you are taught the EpiPen administration procedure. This will ensure that someone close to you will know how to administer the shot should you be unable to do so yourself for any reason. It would be sensible as well to teach several of your family members how to perform the procedure.

The epinephrine in the EpiPen is used to treat the symptoms of anaphylactic reactions in emergency situations. It has to be administered as soon as symptoms of allergic reactions develop.  This could happen within minutes of being exposed to an allergen. Your doctor will advise you of the allergic signs and symptoms to look out for. It is quite likely you'll know whether to use the EpiPen based on your symptoms. You can also find information on the symptoms to look out for in the Anaphylaxis post. There is also a worthwhile video to watch here.

The important thing is not to panic and to inject yourself without asking too many questions. Also, don't worry you'll forget the instructions. For one, the instructions are quite simple, and furthermore they are repeated on the package of the EpiPen. Check out the video below to reassure yourself that you can do it.

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Here's an interesting video showing that you actually need very little pressure to activate the EpiPen. This is important to know, as you could easily eject the needle without realising it.

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You will find all the information you need about the self-injectable syringes on the EpiPen website (US) or the EpiPen website (UK).

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Posted by on May 12, 2013 in The Treatments |

Leukotriene Antagonists

Leukotriene Antagonists

 

This post is still under construction.

Disregard its content, if any, as it only contains raw reference material for the future post.

Show Me!

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