Pharmacy

1. 4TH UNIT
DRUGS FOR ERECTILE
DYSFUNCTION
Prepared by
G. Nikitha, M.Pharmacy
Assistant Professor
Department of Pharmaceutical Chemistry
Sree Dattha Institute Of Pharmacy
Hyderabad
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Subject: Medicinal Chemistry-II
Year: B.Pharmacy 3rd Year
Semister: 1st Semister

2. CONTENTS
 Introduction.
 Causes of Erectile dysfunction
 Drugs used for Erectile dysfunction
 Mechanism of action .
 Structure
 Adverse Drug Reactions .
 Uses.
 Reference
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3. INTRODUCTION
 Erectile dysfunction (ED) and benign prostatic hyperplasia (BPH)
are the common urological disorders in male. ED is the inability to
maintain penile erection for the successful performance of sexual
activity.
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4. CAUSES
 ED has many causes but someone them are vascular disease,
diabetes, medication, depression and sequelae to prostatic surgery.
 BPH is nonmalignant enlargement of prostate, which occur naturally
as men age.
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5. DRUGS USED FOR ERECTILE DYSFUNCTION
 Alprostadil
 Avanafil
 Sildenafil
 Tadalafil
 Vardenafil
All the above drugs are phosphodiesterase-5 inhibitors. But
Alprostadil are synthetic prostaglandin in E1 (PEG1).
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6. PHOSPHODIESTERASE-5 INHIBITORS
 All the four PDE5 inhibitors, Avanafil, Sildenafil, Tadalafil,
Vardenafil are equally effective in treating of ED and adverse effect
profiles are similar. However these agents differ in duration of action
and the effect of food on drug absorption. (Sildenafil, Tadalafil are
also indicated to treat pulmonary hypertension, although the dosage
regimen differ from this indication.
 Taking one of these tablets will not automatically produce an
erection. Sexual stimulation is needed first to cause the release of
nitric oxide from your penile nerves. These medications amplify that
signal, allowing some men to function normally. Oral erectile
dysfunction medications are not aphrodisiacs will not cause
excitement and are not needed in men who get normal erection. 6

7. MECHANISM OF ACTION
 Sexual stimulation result in smooth muscle relaxation of the corpus
cavernosum (penile tissues), increasing the inflow of blood.
 The mediator of this response is nitric oxide (NO). NO activates
guanylyl cyclase, which form cyclic guanosine monophosphate
(cGMP) from guanosine triphosphate produced smooth muscle
relaxation through a reduction in the intracellular (Ca+)
concentration.
 PDE5 enzyme responsible for the degradation of (cGMP) in the
corpus cavernosum.
 The duration of action of cyclic nucleotide is controlled by the
action of phospodiesterase (PDE).
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9. PHARMACOKINETICS
 Sildenafil and Vardenafil have similar pharmacokinetic properties.
 Both the drugs should be taken approximately 1 hour before sexual
activity, with erectile enhancement observed for up to 4 hours after
administration.
 Thus the administration of both of drugs must be timed
appropriately with regards to anticipated sexual activity.
 Tadalafil has lower on set of action than Sildenafil but a significantly
longer half life of approximately 18 hours.
 So it’s approved for once daily dosing. All the inhibitors are
metabolized by cytochrome enzyme.
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10. Sildenafil:
IUPAC: 5-{2-ethoxy-5-[(4-methylpiperazin-1-yl)sulfonyl]phenyl}-1-
methyl-3-propyl-1H,4H,7H-pyrazolo[4,3-d]pyrimidin-7-one
It is a medication used to treat erectile dysfunction, pulmonary arterial
hypertension. It is taken by oral/ I.V route metabolized by liver
through cytochrome enzyme, eliminated through urine.
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Molecular Formula: C22H30N6O4S

11. Adverse Drug Reactions:
 Head ache, heart burn
 Loss of hearing
 Vision problem
 Nasal congestion
 Photophobia,
 Low blood pressure, stroke, heart attack.
Therapeutic Uses:
 Used in the treatment of sexual dysfunction, pulmonary
hypertension, high altitude pulmonary edema, Reynaud’s
phenomenon.
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12. Tadalafil:
IUPAC: 2-(2H-1,3-benzodioxol-5-yl)-6-methyl-3,6,17-
triazatetracycloheptadeca-tetraene-4,7-dione
It is a medication used to treat erectile dysfunction, pulmonary arterial
hypertension. It is taken by mouth, metabolized by metabolized by
liver through cytochrome enzyme, eliminated through urine.
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Molecular Formula:C22H19N3O4

13. Adverse Drug Reactions:
 Head ache, nausea, runny nose
 CVS disease, Low pulmonary artery pressure
 Muscle Pain, Loss of hearing
 Back pain, Vision problem
Therapeutic Uses:
 Used in the treatment of erectile dysfunction, pulmonary arterial
hypertension, benign prostatic hypertrophy.
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14. Reference books
 Text book of Medicinal chemistry volume-1-3rd edition by
V.Alagarasamy.
 Text book of Medicinal chemistry volume-2-3rd edition by
V.Alagarasamy.
 Medicinal chemistry by Rama Rao Nadendla.
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15. THANK YOU
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