An adrenergic antagonist is a drug that inhibits the function of adrenergic receptors. There are five adrenergic receptors, which are divided into two groups. The first group of receptors are the beta (β) adrenergic receptors. There are β1, β2, and β3 receptors. The second group contains the alpha (α) adrenoreceptors.

1. Dr. RITESH MANKAR MD
Dr. RITESH MANKAR MD
‘PHARMACOLOGY MADE EASY’
Adrenergic Antagonist
Adrenergic blocker
Sympatholytic

2. Dr. RITESH MANKAR MD
An adrenergic antagonist is a drug that inhibits the function
of adrenergic receptors.
There are five adrenergic receptors, which are divided into two
groups.
The first group of receptors are the beta (β) adrenergic receptors.
There are β1, β2, and β3 receptors.
The second group contains the alpha (α) adrenoreceptors. (α) 1(α)2
Adrenergic Antagonist
Adrenergic blocker
Sympatholytic

3. Dr. RITESH MANKAR MD

4. Dr. RITESH MANKAR MD
Adrenalin
Clonidine Atenolol
Salbutamol

5. Dr. RITESH MANKAR MD
Amine (non) , sin (α) 1, bin(α)2 , lol(β)

6. Dr. RITESH MANKAR MD

8.
however, the blocking of prejunctional α2-adrenoceptors
leads to increased release of norepinephrine,

9. A condition in which some areas of the body feel numb and cool in certain circumstances.
In Raynaud's phenomenon, smaller arteries that supply blood to the skin constrict excessively in
response to cold, limiting blood supply to the affected area.

12. Phenoxybenzamine belongs to a class of drugs known as non selective alpha blockers.
It works by relaxing and widening blood vessels so that blood can flow more easily.
This medication is used to treat high blood pressure and heavy sweating due to a
certain tumor of the adrenal glands(pheochromocytoma).
S/E
stuffy nose;
mild dizziness or drowsiness;
blurred vision;
trouble having an orgasm;
upset stomach; or.
tired feeling.
DOSE : 0.2 mg/kg PO once daily (Max: 10 mg).

13. Dr. RITESH MANKAR MD

14. Phentolamine is a prescription medication used to reverse numbness after oral and
dental procedures, to prevent and control episodes of dangerously high blood
pressure, to prevent and treat accidental injection of certain drugs,
and also to diagnose a condition called pheochromocytoma
The dose for adults is 5 mg; for children, 1 mg.

15. Pheochromocytoma is a tumor found in the adrenal medulla (the inner part of the adrenal gland).
The adrenal medulla makes the hormones adrenaline (epinephrine) and noradrenaline
(norepinephrine). If a tumor forms in this area, it can cause too much of these hormones to be
made.
Most patients with pheochromocytoma have high blood pressure. Many patients have three main
symptoms: headache, excess sweating and a hard, fast heartbeat (palpitations).
You should see your health care provider if:
You have high blood pressure that is difficult to control
You are taking more than 4 drugs for blood pressure
You have high blood pressure before age 35 or after age 60
You have signs such as:
Bad headaches
Excessive sweating
Racing heartbeat
Paleness
Anxiety and worry
Nervous shaking
Pain in the lower chest or upper belly area
Upset stomach
Weight loss
Feeling overheated
Fatigue
Vision problems

18. The first-dose phenomenon is a sudden and severe fall in blood pressure that can occur when
changing from a lying to a standing position the first time that an alpha blocker drug is used[1] or
when resuming the drug after many months off.[2]
This postural hypotension usually happens
shortly after the first dose is absorbed into the blood and can result in syncope (fainting). Syncope
occurs in approximately 1% of patients given an initial dose of 2 mg prazosin or greater.
The alpha blocker prazosin (Minipress) is most notorious for producing a first dose phenomenon.
Other drugs of the same family, doxazosin and terazosin can also cause this phenomenon, though
less frequently.
The cause is not clear. It occurs more commonly in patients who are salt and fluid volume
depleted (as happens due to the use of diuretics), or were using beta blockers.[4]
prazosin (Minipress) should always be initiated with a low dose and should be taken at bedtime
to avoid standing position.

26. Dr. RITESH MANKAR MD

27. Prazosin is a medication primarily used to treat high blood pressure, symptoms of an enlarged
prostate, and post traumatic stress disorder. It is a less preferred treatment of high blood pressure.
Prazosin should be used with caution in patients with angina pectoris because
severe hypotension may cause or worsen angina.
Prazosin can cause orthostatic hypotension and syncope, which can be hazardous for patients in
certain occupations for which alertness is required.
has been found to be useful in managing sleep-related problems caused by PTSD. It works by
blocking certain alpha-1 receptors in the brain, which might lead to better, deeper sleep
Headache, drowsiness, tiredness, weakness, blurred vision, nausea, vomiting, diarrhea, or
constipation may occur as your body adjusts to the medication.

28. Is dutasteride safe
long term?
Side effects occurring
in therapy
with dutasteride are
decreased libido,
erectile dysfunction,
ejaculation disorders,
and gynecomastia.
However, It may slightly
increase the risk of
developing a very serious
form of prostate cancer

29. Alpha-2 blockers (or α2 blockers) are a subset of the alpha blocker class of drugs and
are antagonists to the α2 adrenergic receptor. They are mainly used in research, having found
limited clinical application in human medicine.
Increases the noradrenaline release due to blockade of alpha-2 receptors.
Non-selective α1 and α2-adrenoceptor antagonists block postjunctional α1 and α2-
adrenoceptors, which causes vasodilation; however, the blocking of prejunctional α2-
adrenoceptors leads to increased release of norepinephrine
Yohimbine is an α2-adrenoceptor antagonist that has been used in the treatment of erectile
dysfunction. At high doses its most common effects are increased blood pressure, slight anxiety,
Alpha-2 blocker
Yohimbe is used as a dietary supplement for impotence, athletic
performance, weight loss, chest pain, high blood pressure, diabetic neuropathy,
and more. Yohimbine hydrochloride, a standardized form of yohimbine, is
available in the United States as a prescription drug for erectile dysfunction.

30. Benefits of Yohimbe
Because of the effect it has on the sympathetic nervous system, Yohimbe helps
to improve blood flow and circulation throughout the body (this is why some
people also use it to help treat erectile dysfunction). Yohimbine can act as a
vasodilator (meaning it causes the blood cells to expand)
Diabetes: Don' t use yohimbe. Yohimbe might interfere with insulin and other
medications used for diabetes and cause low blood sugar.
The FDA removed yohimbine from prescription status in mid-90s because of its
potential for harm, he said. But it was never banned in the United States, and “it
has found its way back onto the market in herbal supplements and dietary aides,
Hyde NitroX is our only pre–workout supplement made with yohimbine — in the
form of Yohimbe bark extract. As it's a pre–workout supplement, it's best to
consume Yohimbe between 15 and 30 minutes prior to exercising.
Yohimbine is a herbal preparation enhances plasma testosterone levels and
promotes skeletal muscle hypertrophy, sexual vigor, and decreased body fat