A patient approached me two days
ago to ask me if his doctor who gave him Terazosin was the right medication for
his prostate enlargement (benign prostate hypertrophy - BPH)? He told me he has
high PSA, and if this meant he had cancer of the prostate?
I explained and assured him
this drug is popularly used by doctors for managing BPH. But also told him
Terazosin is hardly used for treating hypertension as its action is more marked
in bringing down blood pressure quite rapidly than its effects on urodynamics.
Since I have almost forgotten my
pharmacology, I decided to carry out a medical experiment only on myself to
demonstrate the hypotensive effects of this agent (Terazosin). But first allow
me to very, very briefly explain the chemistry and action of this drug.
Chemical name:
1-(4-amino-6,7
-dimethoxy-2-quinazolinl)-4-(tetrahydro-2-furanyl) carbonyl -Piperazine
monohydrochloride dihydrate with the empirical formula C19H25N5O4.HCl.2H2O
Generic name: Hytrin
Terazosin is presented at 1 mg, 2
mg, 5 mg. Initial starting dose is 1 mg, titrated to higher doses as per
necessary.
Pharmacology:
Its pharmacodynamic (mode of
action) is, it is a blocker of alpha-1—adrenoceptor and is indicated for
hypertension that can rapidly induce hypotensive effects even after a small
initial dose. This can be used as the first line treatment. It also improves
urodynamic on the smooth muscle tone of the bladder as second line action. This
it does by antagonizing the phenylephrine induced contractions of the bladder
regulated by alpha-1-adrenergic receptors.
It is actually a marked hypotensive
agent, but mainly prescribed for benign prostate enlargement (BPH) in males
instead.
Since now I have briefly explained
its pharmacodynamics as a very effective antihypertensive drug it is used
instead for managing benign prostate hypertrophy.
I then decided to conduct a
personal medical experiment on myself to evaluate how effective it is as an
anti-hypertensive agent.
Study Design:
First of all, straight away and at
once I need to mention what I conducted on myself is NOT a properly designed
study. I did not use large populations or small randomized samples to
statistically represent large true populations with controlled / placebo groups
to compare, groups on the medication and groups not on the medication.
The data collected should then be
statistically analysed to look for ‘statistical significance’ to see if there
is a REAL difference, and not a difference due to chance between the test group
(on medication) and the controlled group (not on medication). We, as
former medical researchers, would normally follow very strict experimental and
statistical protocols in our study designs and how we select our samples.
We then use sophisticated
mathematical (statistical) procedures to analyse the data before we interpret
the data and results.
This is the first thing I need to
explain right here at the very beginning. Once again, I am only using myself as
the only subject that would not be representative of any population. Besides,
there was no control group, not even another one person to compare, let alone
the experiment carried over and over again for consistency. It was only a
few measurements over a 12-hour period.
Finally, normally we do not give
the date or the clock’s time on the watch as I did here. Normally we may record
the time taken as 10 minute, 15 minutes, 30 minutes …2 hours…20 hours
intervals, but not the date or actual time on the clock as I informally do here
unless we want to show nocturnal and daytime variations.
Here are the very few data not
worth any statistical analysis. Once again, I want to emphasize we need large
samples, as large as possible to represent a true population, and the sampling
we take must be randomized to prevent bias. Bear in mind these are
some of these research criteria required and must follow before I start. Are we
ready?
However, despite these flaws here
with only myself on this experiment, it already gives us a hint as a pilot
pointer that Terazosin do have antihypertensive action on blood pressure and
can be indicated for the management of high blood pressure instead of prescribing
it only for BPH as doctors do.
We may use these small initial
results as a springboard for much larger, and properly designed study
Results:
Blood Pressure with 2.5 mg
Terazosin (Hytrin)
Tuesday – Wednesday: 28 – 29 March
2023
Time and blood pressure
Prior to dosing at 10:15 pm: 116/
67, 119/66, 126/71 mm Hg (Normotensive)
10:25 pm after oral dosing with 2.5
mg Hytrin: 119/72, 99/61, 107/ 65 mm Hg
10:36 pm: 97 /67, 110/73. 116/69 mm
Hg (initial stage of hypotensive)
10:45 pm: 105 / 64, 108/60, 116/69
mm Hg (mild hypotension)
11:00 pm: 112 / 64, 115 /72, 102/
59 mm Hg
Midnight, 29 March 29, 2023: 89 /
56, 82 / 50, 87 / 53 mm Hg. (Marked hypotension)
1:05 am: 83 /58, 82 / 52, 94 / 65
mm Hg (hypotensive stage)
3:13 am: 110 / 69, 106 /65, 117 /
74 mm Hg (drug effect showing false signs of wearing off)?
4:02 am: 80 /56, 94 /62, 96 / 64 mm
Hg (hypotensive stage maintained)
10:39 am: 135 /71, 124 /72, 118 /80
mm Hg (hypotensive action weaning off after 12 hours)
Far too small a sample for
statistical analysis. But we can see a quick rapid drop in blood pressure
within just 15 minutes after an initial 2.5 mg. dose was maintained for 12
hours.
But I am unsure why is Terazosin seldom
used to treat hypertension instead of other antihypertensive agents such as
valsartan or valsartan with a diuretic such as valsartan + hydrochlorothiazide
(Co-Diovan)? There is no indication in the literature to show the adverse
effects of using Terazosin alone or concomitantly with other drugs for treating
hypertension.
Prostate-specific Antigen (PSA)
As far as his high total
prostate-specific antigen (PSA) is concerned, this needs to be investigated
further. A high PSA level does not necessarily mean prostate cancer, and
neither a low PSA level means the absence of prostate cancer. One of the best
ways to detect prostate cancer is to look at how high and fast the PSA levels
rise over a period of time (PSA velocity).
If it rises far above the normal
of 4.0 ng/mL within a month
or so, this requires further investigations using urine tests, such
as a urinalysis for blood, TRUS (trans rectal ultrasound) biopsies, x-rays,
cystoscopy. TRUS biopsies are very invasive that also carries the risk of
infections as the needle has to go through the distal end of the colon where
there are faeces, and risk of bleeding as multiple sites, some 10 to 12 areas
around the prostate gland needs to be punched out (biopsied).
One better non-invasive approach
is not just taking blood to determine level of free PSA, but to look for
combined PSA with protein. But this method is very time consuming and very
expensive to carry out. I have not heard of this free and combined PSA being
done in any of the government hospitals in this country, but I have no idea if
this is available in private hospitals? Since it is expensive and
time-consuming, free and combined PSA is not routinely done in most government
hospitals, not even in major ones. They may also need lab facilities and
trained staff to do this
Patients with low free
to total PSA in blood may be at risk of prostate cancer. PSA
ratios of less than 10% free PSA, and more than 90% bound PSA is more likely to
have prostate cancer. Men with constantly elevated PSA concentrations should
have the free to total PSA ratio estimated. The only problem with this test is
that free PSA is short-lived not only in vivo but also in vitro, so it must be
measured within 24 hours of collecting the blood sample. Delay will falsely
lower free to total PSA ratios which could be misinterpreted as an increased
risk of cancer.
Jb lim
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