OTC ED Products

Question 1

Available Products over the counter for EDs

Answer 1

Sildenafil (Viagra/Generic) - 50mg
Tadalafil (Cialis) - 10mg

Question 2

How Does Tadalafil Work?

Answer 2

Tadalafil is a selective, reversible inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5). When sexual stimulation causes the local release of nitric oxide, inhibition of PDE5 by tadalafil produces increased levels of cGMP in the corpus cavernosum. This** results in smooth muscle relaxation** and inflow of blood into the penile tissues, thereby producing an erection. Tadalafil has no effect in the treatment of erectile dysfunction in the absence of sexual stimulation.

Question 3

How Does Sildenafil Work?

Answer 3

The physiological mechanism responsible for erection of the penis involves the release of nitric oxide (NO) in the corpus cavernosum during sexual stimulation. Nitric oxide then activates the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate (cGMP), producing smooth muscle relaxation in the corpus cavernosum and allowing inflow of blood.

Sildenafil is a potent and selective inhibitor of cGMP specific phosphodiesterase type 5 (PDE5) in the corpus cavernosum, where PDE5 is responsible for degradation of cGMP. Sildenafil has a peripheral site of action on erections. Sildenafil has no direct relaxant effect on isolated human corpus cavernosum but potently enhances the relaxant effect of NO on this tissue. When the NO/cGMP pathway is activated, as occurs with sexual stimulation, inhibition of PDE5 by sildenafil results in increased corpus cavernosum levels of cGMP. Therefore sexual stimulation is required in order for sildenafil to produce its intended beneficial pharmacological effects.

Question 4

Definition of ED

Answer 4

Erectile dysfunction has been drfined as the inability to attain and/or maintain an erection hard enough for satisfactory sexual intercourse.
- It can occur occasionally or frequently
- Can range from mild(soft erection) to severe(no erection)

Question 5

Causes of ED

Answer 5

**Psychological Causes: **Psychological inhibits normal stimuli to and from the brain, interfering with the ability to achieve a normal erection.
- Purely psychological causes only account for around 1 in 10 cases
- Possible psychological causes include; performance anxiety, depression, antidepressants, lack of arousal/inhibiton between partners, other sexual dysfunction(premature ejaculation), major life stresses(money worries, bereavment…), low self-esteem, indifference(loss of interest/probelems in a relationship).

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Medication Side Effect:

Question 6

Medications That Can Cause EDs

Answer 6

Some drugs (iatrogenic cause) can directly cause EDs, others are used to treat diseases that are associated with EDs so its not fully understood if its a drug side effect or the disease side effect.
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Recrational drugs; casuse vasoconstriction &/or impacts on neurotransmitters in the erectile pathway.
- alcohol
- heroin
- marijuana
- methadone)

Cardiovasular Drugs;
- Diruetics (not determined believed to interfere with smooth muscle relaxation)
- ACE/ARBs (interfere with smooth muscle relatation)
- Aldosterone antagonists (anti-adrenergic action)
- Beta-Blockers (affects sex hormones, impairs vasodilation of corpora cavernosa).
- Clonidine (depresses adrenergic output)

Psychotropic Drugs;
- Anti-depressants (SSRIs/Tricyclics/MAOIs/lithium) - decrease arousal & desire.
- Anti-psychotics (Phenothiazides, butyrophenones) - increases prolactin levels.

Anti-epileptics: Affect sex hormone levels
- Carbamazepine
- Phenytoin
- Barbiturates

Endocrine Drugs: Affect androgen receptors, reducing sexual desire
- Testosterone antagonists/oestrogen agonists
- Anabolic steroids
- Luteinising hormone-releasing hormone analogues

Other:
- H2 antagonists (ranitidine/cimetidine); increase prolactin levels reducing sexual desire.
- cytotoxics (cyclophosphamide, methotrexate); nausea & general malaise associuated with such drugs often dimish libido.

Question 7

What can get Sildenafil OTC?

Answer 7

Men 18+ with ED

Question 8

Who to refer to the doctor for 25mg sildenafil dose?

50mg is only P medicine (100 &25mg are POMs)

Answer 8

• Renal Impairment
• Hepatic Impairment
• On CYP3A4 inhibitors or alpha blockers
• Those with tolerability issues to the 50mg.

Question 9

Who To Refer To GP for sildenafil?

Answer 9

• 50mg not working effectively enough (may need 100mg dose)
• -

Question 10

Who To Refuse Sildenafil Sale