Download L07.OTC - ISpatula

In this lecture we shall cover the issue of pharmacologic treatment ,
ANC is defined as the acid neutralizing capacity for a select H2 blocker , ie , its
buffering capacity against an acidified solution , please note that calcium
carbonate is the strongest antacid , and it also has the advantage of providing
elemental calcium to pregnant females ,however , at or near its maximum dose 6 grams per day- ,it may cause constipation , also note that antacids which
contain aluminum have the same side effect of constipation , while magnesium
containing antacids may cause diarrhea .
Antacids are to be taken after food , they are also not meant to be taken as
prophylaxis in gerd patients , this is due to the fast onset of action they inherently
have , as well as the short duration of action which is 20 to 30 minutes , and may
on occasions rise to about two hours , and hence , taking H2 blockers before a
meal would be considered counterproductive as its effect will most likely be
diminished before the patient is done with his meal
Antacids show drug drug interactions with di and trivalent cations , and caution
must be taken if drugs which are effected by chelation eg , floroquinones- , must
be administered , in this case the quinones must be taken two hours after the
antacid , or one hour prior to it .
The fastest antacid preparation , ie shortest onset of action , is the bicarbonate ,
potassium shows a slight faster onset of action than sodium , but both are
considered rapid acting , potassium bicarbonate is available in jordan as gaviscon
advance , which in addition to sodium alginate , has potassium bicarbonate acting
as an antacid ,
Unlike potassium bicarbonate , sodium bicarbonate is available solely as a
preparation eg Eno , and its also available in pharmacies , as well as in regular
stores where it is known as baking soda , known to arab households as ‫ كربونة‬,
the difference between pharmaceutical sodium bicarb preperations and the one
found in the stores is the masked and improved taste in the pharmaceutical
preparation
For a slight intro on gaviscon , note that it has a natural sodium alginate which
forms a protective layer separating the gastric content and the esophageal
mucosa , gaviscon as such is only composed of sodium alginate , gaviscon advance
on the other hand has double strength sodium alginate and also has potassium
carbonate to aid in the buffering of the stomach , with a duration of action of
about 3 to 4 hours , please note that the patient must refrain from laying down or
going to sleep immediately after taking gaviscon as the surface are of the gastric
content increases while laying down , and so the efficacy will decrease
Gaviscon pills are considered extremely hard to swallow , while the suspension is
much more palatable
Another non approved use of gaviscon can be to treat vomiting in infants and
pregnant females due to the protective layer it forms between the stomach and
the esophagus , thereby mechanically preventing vomiting , this is of valuable use
because the sodium alginate doesn’t get absorbed into the blood stream , and
causes no harm to the infant , or to the fetus in case of pregnancy
Please note that if a patient is on a restricted potassium and sodium , then they
have to be aware of the presence of those salts in gaviscon
Table 14-3 depicts the efficacy in relation to onset of action and duration of action
to different treatments of antacids , remember that sodium bicarbonate takes
effect in a couple of seconds , while other antacids need about 5 minutes to take
effect , the other parameters were mentioned by the doctor and should be
memorized , H2 blockers normally have an effect of 10 hours , and hence they
are taken twice daily , with the exception of cimetidine which has an effect of 4
hours , the Doctor also mentioned a product sold in the US by the name of
PEPSID-AC , which contains famotidine and sodium bicarb , which are safe to take
unlike in the case of PPI were mixing h2 blockers , antacids and PPIs is indeed
problematic
Moving on to PPIs , note that their onset of relief is 2-3 hours , and that can
extend to 24 hours , which averages a 6 hour duration of relief for most patients ,
and based on that , PPIs should be taken in the morning before breakfast , if
otherwise , there’ll be a gap in treatment with no coverage , the duration of
action is 12 hours and up to one week , some people take a ppi for heart burns ,
without suffering from gerd and so once capsule will likely give them relief for 3
to 5 days , patients who have gerd , however , will likely be relieved for 24 hours
and must take another capsule then.
In the case of abruptly stopping the PPI , patients will be subjected to worsening
conditions of heart burns for two reasons , the first of which is that the body
produced more gastrin in reflex to the blocked proton pumps , the second of
which is that proton pump turnover is hastened from about 54 hours to 24 hours ,
as a result ,when stopping the ppi , more acid will be secreted into the stomach ,
For patients who have moderate to severe GERD , ie , grade 2A and up , a
maintenance therapy is needed , which is defined as the lowest effective dose of
the acid suppressor treatment , and so , hypothetically , if a patient is on a
standard dose of omeprazole and he or she wanted to stop it , then the patient is
faced with two options , either lower the dose of ppi , or switch to a high dose H2
blocker , decreasing the frequency of administration is also an option , ie , taking
ppi every other day with high dose H2 blocker in between , if this wasn’t enough ,
and the patient returned to having the same symptos , then they should return to
their original treatment of ppi , this really has to do with whether the underlying
cause of the gerd is healed or not , a patient can quit his ppi after a week’s
therapy and switch to ppi prn if healing is determined ,
Slide 56 has a table pertaining to equivalent doses , please memorise this table
and keep in mind the following ; PPIs are not to be replaced due to inadequate
treatment , in this case , we increase the dose , it is common though , that a
patient wishes to use another ppi due to price differences and drug availability ,
also note that in the US , ranitidine is present as syrup and can be given to
children aged one month and older , whereas famotidine can be given to children
3 months and older
PPIs shouldn’t be crushed , and hence , when administered to children should be
placed in apple sauce or other beverage which can be swallowed whole without it
being crushed , this reduces the effect of undermining the release of the coated
pellets , omeprazole has a special method of administration to children , where if
the child weighs more than 20 kgs , they can take the 20 mg dose , otherwise , the
10 would be sufficient , also , omeprazole can be prepared as a suspension with 8
ml eq of sodium bicarb to facilitate the forlmula , after which it will expire after
only 24 hours .
There is absolutely no indication whatever for injectable PPIs other than the fact
that the patient hasn’t the ability to take oral PPIs , IV PPIs are in fact faster to be
eliminated and have less chance of reaching parietal cells .
Among the PPIs , Pantoprazole is considered the it’s the most acid stable , it has a
fast onset, the longest t half , the most stable binding with pp , that however
doesn’t mean it is superior to other PPIs , this only means that if , for example a
patient was on omeprazole , and he or she didn’t improve with the increased
dose of omeprazole , then pantoprazole is a genuine alternative . please note that
the issue of irreversible inhibition Is related to time as well as stability of binding ,
and so even with irreversible inhibitors , it is possible that the binding is broken
between the PP and the PPI .
Pantoprazole also effects the PP turnover rate the least , maintain a 40 hours turn
over rate for PP as opposed to the 24 hour with the rest of the PPI , it is also the
only PPI with linear kinetics , ie , doubling the dose should lead to double the
effect , unlike omeprazole and esomeprazole . Another kinetic issue with
omeprazole is that the effect of it increases with time due to the drug itself
inhibiting its own clearance , so it is recommended to take omeprazole on daily
bases rather than as prn , especially in gerd
Rabeprazole has the fastest onset of action , it produces what is thought to be an
irreversible inhibition due to its slow dissociation and prolonged effect
Reasearch is now put into discovering a reversible PPI with a long T half , such as
Tenatoprazole , with a t half of 17 hours , and reversible inhibiton of ppi
Please note that reversible PPIs reduce risk of side effects and undesirable
events , acute risk is infections , pneumonia and clostridium defficile , while
chronic use risk is the increased chance of osteoporosis . the doctor also
claimed that renal risk of ppi and stroke risk are not well established and
shouldn’t be taken as such .
The doctor concluded the lecture with mentioning Dexlansoprazole dual release
as being more effective because of the dual release dose 30-60 , as well as the
fact that it isn’t meal related
Also note that in all fields of Gerd , ppi’s are considered more effective than other
medications . there is also a new category of treatment based on prokinetic
method of increasing gastric motility and relieving pressure off of the stomach
with drugs like metoclopramide I, it is however not selective , and its use has not
yet been standardized , and so if doubling the dose of ppi didn’t relief the
symptoms , currently , we are only faced with the choice of surgery
This concludes the lecture , good luck