pharmacology

1. Clinical pharmacology
ANS 5
Anti -Adrenergic
Alpha blockers

2. Physiological point
We have two types of Baro- reflexes :
First type : During supine position the blood equally
distributed on body , However during prolonged supine
position followed by sudden standing position this leads to
blood pooling from upper half of the body into lower half ;
this pooling effect may causes hypotension , so the
counteract mechanism of the body to prevent this
condition it causes reflex vasoconstriction in lower
extremities .

3. Physiological point
If vasoconstriction of blood vessels in lower
extremities delayed (or absent), which is normally
required to maintain an adequate blood pressure when
changing position to standing. As a result, blood pools
in the blood vessels of the legs for a longer period and
less is returned to the heart, thereby leading to a
reduced cardiac output and inadequate blood flow to
the brain this condition is termed as orthostatic or
postural hypotension.

4. Orthostatic Hypotension
Orthostatic hypotension is a medical condition
wherein a person's blood pressure drops when
standing up or sitting down.
The drop in blood pressure may be within 3
minutes or gradual (delayed orthostatic
hypotension).
It is defined also as a fall in systolic blood
pressure of at least 20 mm Hg or diastolic blood
pressure of at least 10 mm Hg when a person
assumes a standing position.
.

5. TCA such imipramine and amitriptyline

6. treatment
Treated by phenylephrine or effortil (vasoconstriction drugs)
2) Baro Refluxes
Aortic arch baro reflex
If sudden increases in BP more than 170mmHg ( by drugs or
other causes) this leads activation of stretch receptor in
Aortic arch that sends reflex to cardio-inhibitory center in
medulla leading to activation of vagal nerves causing
bradycardia , this called reflex bradycardia ; on the other
hand sudden lowering of blood pressure , stretch receptors
will sends to sympathetic system that causes reflex
tachycardia

7. Exception :
if the causative hypertensive factor is adrenaline
(hypertension ) the reflex bradycardia not appear..
Why ?
Because when stretch receptor sends to medulla
the reflex from vagus not correct the hypotension
since adrenaline is strong stimulator to b1 receptor
in heart that prevent this reflex bradycardia..
Also if we give beta blocker and causes hypotension
, the stretch receptor send to sympathetic system
that however blocked by these drugs so the reflex
tachycardia not occur

8. .
.

9. Alpha adrenergic blockers
We have 3 family
1) Non selective alpha blockers {phenoxybenzamine
and phentolamine }
2) Selective alpha 1 blockers {Prazosin, terazosin ,
Doxazosin , tamsulosin , alfazosin }
3) Selective alpha 2 blocker { yohimbine}

10. Classification
1) According to their reversibility and duration of action.
A)Irreversible, Long-Acting:
Phenoxybenzamine is the prototypical long-acting,
irreversible α blocker.
It is important in the treatment of pheochromocytoma
because a massive release of catecholamines from the
tumor .
B)Reversible, Shorter-Acting:
Phentolamine is a competitive, reversible blocking
agent that does not distinguish between α1 and α 2
receptors.

11. phenoxybenzamine
Irreversible Blocker of α 1 and α 2 receptor (covalent
bond).. Duration as long as receptor life span (4days).
Action :
hypotension (α 1) followed by reflex tachycardia
Indication :
-Phaeochromocytoma (tumor)
-benign prostatic hypertrophy (X)
-malignant essential hypertension (X)
Side effect :
hypotension ,
reflex tachycardia ,and
miosis

12. 2) According to Selectivity
A- Alpha1-Selective
Prazosin , alfazosin , terazosin and Doxazosin are highly
selective, reversible pharmacologic α 1 blocker., and
tamsulosin {; More selective one α 1-D blocker }
Uses : treatment of hypertension ( but with reflex
tachycardia S/E).
The more selective α1-D blockers, tamsulosin (omnic ®) is
also extensively used in the management of benign
prostatic hyperplasia , renal calculi (ureter ) and urinary
retention in patient with horse shaped
kidney)
Pharmacological action of α1-selective blockers
-Vasodilators
-Hypotension { with reflex tachycardia}
-Not associated with reduce renal blood flow
-Improve lipid profile (decreases cholesterol and TG)

13. .

14. Clinical uses
1-HT { esp : with renal failure or hyperlipidemia}
2- Acute heart failure { decreases venous return (preload) and
after load preload : amount of blood reach right atria through
vena cava ….While
afterload is resistance that faces left ventricular through
pumping blood to aorta
Alpha 1 blockers causes dilatation of venous vena cava leading
to decrease preload i.e. blood not strongly injected into heart
Also these drugs decreases afterload by dilatation mechanism
The superior vena cava is the large vein which returns
blood to the heart from the head, neck and both upper
limbs. The inferior vena cava returns blood to the heart
from the lower part of the body.
3. Benign prostatic hyperplasia { alpha1 D blocker tamsulosin
is more preferred why?)
4.Raynuds phenomena

15. Raynaud’s phenomenon
is a problem that causes decreased blood flow
to the fingers. In some cases, it also causes
less blood flow to the ears, toes, or nose. This
happens due to spasms of blood vessels in
those areas. The spasms happen in response
to cold, stress, or emotional upset.

16. Case 5

17. Case 5

18. Question
Selective alpha blockers are Vasodilators so they causes
decrease blood pressure which may associated with reflex
tachycardia but less than that causes by non selective alpha
blocker (phenoxybenzamine) why?
Answer :
1. Alpha 1 blocking causes hypotension and reflex
tachycardia
2. Alpha 2 blocking causes increases NE that act on
beta 1 receptor in heart so causes more strong
tachycardia
Two sources of tachycardia in non selective type

19. Side effects
1-First dose syncope (esp in dehydrated patient).
To avoid : decrease dose of first dose to ¼ tab and taken
immediately before sleep.
2. Postural hypotension
3. Fluid retention : by prolong use as a result from
chronic hypotension that stimulate rennin secretion as
compensatory mechanism that cause sodium water
retention
To avoid : prescribe diuretic
4. False positive test for anti- nuclear antibodies (
diagnostic test RA and SLE)
5. Aggravate urinary incontinence

20. B- Alpha2-Selective
Is orphan drug
Yohimbine is α2-selective competitive blockers.
Recently yohimbine can be used in treatment of obesity
however there is no scientific evidence for this indication.

21. Disorders Treated With Alpha Blockers

26. Treatment
1.Surgical
2. Pharmacological
A. Initiation of alpha blockade (phenoxybenzamine ,
dose of 10 mg twice daily )
B . Beta-blockers ( propranolol )..
However it should never be introduced prior to
adequate alpha blockade (due to the risk of
unopposed alpha receptor stimulation-adrenergic
stimulation that leads to severe vasoconstriction which
may causes cerebral hemorrhage).
Generally, alpha blockade is given at least 1-2 weeks
prior to surgery

27. 2) RENAL STONES…
.
Ureter stone
Patients with active stone passage generally present
with pain and either microscopic or macroscopic
hematuria .
The site of obstruction determines the location of pain
. A stone in the renal pelvis or upper part of the ureter
usually causes flank pain , where as a stone in the
middle or lower ureter causes radiation of pain to the
groin and genitalia .
Obstruction at the terminal ureter usually results in
signs and symptoms that mimic those of cystitis (F , U,
D ) as well as pain in the lower abdomen.

29. Types of urinary stones

30. Tamsulosin (Omnic®)has been found to increase and
hasten stone expulsion rates, decrease acute attacks by
acting as a spasmolytic and reduces mean days to stone
expulsion
This medicine may increases the rate of stone passage
by about 30%.

31. 3) Benign prostatic hyperplasia BPH

33. Features of BPH

35. Treatment Benign prostatic hyperplasia
Rx
The two main medications for management of BPH
are
1) alpha blockers.
Alpha blockers are the most common choice for initial
therapy .
Alpha blockers used for BPH include Doxazosin,
tamsulosin.
2)The 5α- reductase inhibitors finasteride
(prostacare®) This medicine inhibits 5a-reductase,
which in turn inhibits production of DHT, a hormone
responsible for enlarging the prostate.
Effects of finasteride may take longer time {6 mo. to
appear } that reduces the size by 30%, but they persist
for many years.

37. .
Other uses of finasteride
1) Male pattern alopecia { in male and female }
Finasteride (prohair tab 1mgl day) plus Minoxidil spray 2% for
female and 5% for male)

38. 2) Hirsutism in female:
Most commonly due to
A-poly cystic ovarian syndrome (pcos ; prevalence
20%)
{ DX: clinical : obesity , hirsuitism , mc irregularity ; u/s
show many antral folicules;
hormones : ↑↑↑anti-mullerian hormone (AMH)
Also → LH/FSH ≥ 1.5
B-thyroid disease
C-hyperandrogenism
D-supersensitivity of hair follicles to normal level of

39. Case 1
A 57-year-old male presents to his family physician complaining
of episodic headaches, sweating, heart palpitations, and a tremor.
The symptoms started a few years ago, have become more
frequent, and can last anywhere between a few seconds to an
hour. The episodes often occur when the patient feels stressed or
exercises. He is not on any medications. He has a family history
of hypertension. He does not use tobacco products, cocaine,
methamphetamines. He has not had fevers, chills, chest pain,
shortness of breath, nausea, vomiting, or diarrhea.
On physical examination, vital signs showed an elevated blood
pressure of 168/96 mm Hg, tachycardia of 116 beats per minute,
a respiratory rate of 20 breaths per minute, and a temperature of
98°F (36.66°C). Physical examination reveals a diaphoretic male
with no cardiopulmonary abnormalities other than the previously
mentioned tachycardia.

40. 1) What Is the Differential Diagnosis Based on the History and
Physical Examination?
The differential diagnoses include: pheochromocytoma, essential hypertension,
anxiety disorders, panic attack, thyrotoxicosis, medications, amphetamine and cocaine
abuse, paroxysmal supraventricular tachycardia.
A good medical history and imaging studies :
Laboratory Studies
The complete blood count, comprehensive metabolic panel, D-dimer, and serial
troponins were within reference ranges. An ECG indicated sinus tachycardia and left
axis deviation consistent with left ventricular hypertrophy. A 24-hour
Urinary metanephrines were 1300 µg/24 hours (normal range: 45-290 µg/24 hours).
Imaging
A chest X-ray was performed demonstrating mild left ventricular hypertrophy. Cardiac
ultrasound demonstrated ventricular hypertrophy. An abdominal computed
tomography (CT) scan showed a 3-cm-diameter left adrenal gland mass..
Imaging and lab studies indicate a condition of pheochromocytoma

41. Case 2
A 62-year-old man presents with a 4-year progressive history of:
•Increasing lower urinary tract symptoms
•Flow rate: 11 mL/s
•Post-void residual: 60 mL
•Prostate volume (on transrectal ultrasonography [TRUS]): 65 mL
•Prostate-specific antigen (PSA) level: 3.2 ng/mL
The patient states that he is not bothered significantly by his symptoms and does not
desire active therapy.
1-What is his risk of progression?
R / This patient is at significant risk for benign prostatic hyperplasia (BPH)
progression:
2-What is the most appropriate medical therapy?
5-α-Reductase inhibitor therapy, combination 5-α-reductase inhibitor and α-blocker
therapy.
Evidence exists that the patient will do well if α-blocker therapy is discontinued at 9
to 12 months and the 5-α-reductase inhibitor is continued indefinitely.

42. Case 3
A 56-year-old man has a 2-year history of increasing voiding symptoms:
•Peak flow rate: 15 mL
•Post-void residual: 10 mL
•Prostate volume (on TRUS): 25 mL
•PSA level: 0.9 ng/mL
This patient has bothersome symptoms and desires treatment.
1.What is his risk of progression?
The risk of BPH progression in this patient with a small prostate and low
baseline serum PSA level is low.
2. What is the most appropriate medical therapy?
α-Blocker therapy
The patient begins α-blocker therapy and, within several weeks, reports
significant symptom amelioration.
Implications for therapy:
Although bothered by his symptoms, this patient has a low risk of BPH
progression. He is an ideal candidate for long-term α-blocker therapy.

43. Case study 4 : What is the diagnosis of this condition?

44. Case 5
A 25-year-old man, presented with recurrent episodes of dull
aching right flank pain , abdominal bloating , urinary retention
and peripheral edema of 6-year duration. The preoperative CT
scan revealed a horseshoe kidney (HSK) with the right side
involved by ureteropelvic-junction obstruction (UPJO) causing
gross hydronephrosis and parenchymal thinning .
The relative renal function was 50% on renogram. The left renal
moiety was functioning well with a GFR of 71.9 ml/min. The S.
Creatinine was 0.9 mg/dl
1.What is his risk of progression?
There is risk of frequent UTI and formation of renal calculi
2. What is the most appropriate medical therapy?
Alpha 1 blockers tamsulosin is drug of choice , with avoidance food that
triggers such as tea , coffee and spicy

45. Case 6
An 14 years old female in good general health
suffered frostbite from 09.00 to 16.00 on February
.she complained intensive pain, discoloration, lack of
sensitivity and limited movement on her toes.
1. What is the diagnosis of this condition?
2. Give 3 optional treatment for management of this
case?

46. 1- What is the diagnosis of this condition?
Cold frostbite = Perniosis
2. Give 3 optional treatment for management of this
case?
1- alpha blocker (alfazocin SR)
2- Ca channel blocker (Nifedipine SR)
3- Phosphodiestrase inhibitor (Pentoxifylline or cilostazol )
They are also used to improve the symptoms of intermittent
claudication due to occlusive artery disease).
Pentoxifylline can decrease the muscle
aching/pain/cramps during exercise, including walking, that
occur with intermittent claudication.

47. Toxicity
Major adverse effects of alpha adrenergic blockade:
-Hypotension
-Orthostatic hypotension
-Reflex tachycardia
.