Tadalafil Pharmacology


About Tadalafil
A Phosphodiesterase 5 enzyme inhibitor, Treating erectile dysfunction (ED).
Mechanism of Action of Tadalafil
Tadalafil is a phosphodiesterase enzyme (PDE5) inhibitor. This enzyme is responsible for the degradation cyclic guanosine monophosphate (cGMP) produced in reaction to sexual stimulation. The more cGMP is available, the more durable the erection. Tadalafil inhibits the PDE5 enzyme, preserving cGMP levels, therefore aiding erection viability and durability
Erection of the penis is caused by the filling of the penis with blood. Filling occurs because the blood vessels that bring blood to the penis increase in size and deliver more blood to the penis, and, at the same time, the blood vessels that take blood away from the penis decrease in size and remove less blood from the penis.
Sexual stimulation that leads to an erection causes the production and release of nitric oxide in the penis. The nitric oxide causes an enzyme, guanylate cyclase, to produce cyclic guanosine monophosphate (cGMP). It is the cGMP that is primarily responsible for increasing and decreasing the size of the blood vessels carrying blood to and from the penis, respectively, and causing the erection. When the cGMP is destroyed by another enzyme, phosphodiesterase-5, the blood vessels return to their normal size, blood leaves the penis, and the erection ends. Tadalafil prevents phosphodiesterase-5 from destroying cGMP so that cGMP stays around longer. The persistence of cGMP leads to a more prolonged engorgement of the penis with blood. It relaxes muscles and increases blood flow to particular areas of the body.
Pharmacokinets of Tadalafil
Absorption: It is readily absorbed from the bloodstream and the bioavailability is only 16%.
Distribution: It is distributed in protein bound form (94% bound to plasma protein).
Metabolism: It is metabolized in the liver by an enzyme known as CYP3A4.
Excretion: It is excreted in the feces (61%) and in the urine (36%).
Onset of Action for Tadalafil
Duration of Action for Tadalafil
Half Life of Tadalafil
17.5 hours
Side Effects of Tadalafil
1. Facial flushing
2. Headaches
3. Stomach upset
4. Diarrhea
5. Flu-like symptoms
6. Nausea
7. Back pain
8. Muscle aches
9. Low blood pressure
10. Blurred vision
11. Abnormal ejaculation
12. Prolonged erections
13. Sweating
14. General ill feeling
15. Irregular heartbeat
16. Swelling in hands, ankles, or feet
17. Shortness of breath
18. Lightheadedness
19. Fainting
In pre-existing heart disease:
1. Chest pain
2. Heart attacks
3. Death
4. Strokes
5. Palpitations and increased heart rate
6. Vision changes

Contra-indications of Tadalafil
1. Patient on nitrate therapy
Special Precautions while taking Tadalafil
1. Do not take Tadalafil more than once a day
2. Contact doctor if erection is painful or lasts longer than 4 hours
3. Heart disease
4. Recent history a heart attack (within the past 90 days)
5. Recent history of stroke or congestive heart failure, (within the past 6 months)
6. Angina
7. Hypotension
8. Hypertension
9. Liver disease
10. Kidney disease
11. Sickle cell anemia
12. Multiple myeloma
13. Leukemia
14. Haemophilia
15. Stomach ulcer
16. Retinitis pigmentosa
17. Peyronie`s disease (physical deformity of the penis)
18. Diabetes
19. High cholesterol
20. Pre-existing eye problems
21. One who smoke or are over 50 years old
Pregnancy Related Information
Old Age Related Information
Use with caution
Breast Feeding Related Information
Children Related Information
NEONATES: Contraindicated
Indications for Tadalafil
1. Treatment of impotence.
Interactions for Tadalafil
Nitrates: Tadalafil increases the effect of these drugs.
Typical Dosage for Tadalafil
Initial dose: 10 mg / day taken 30minutes - 12 hours before sexual activity. Depending on the adequacy of the response or side effects, the dose may be increased to 20 mg or decreased to 5 mg a day.

Schedule of Tadalafil
Storage Requirements for Tadalafil
Store at room temperature between 15-30?C. Protect from moisture and heat.
Effects of Missed Dosage of Tadalafil
Tadalafil is used as needed, not likely to be on a dosing schedule.
Effects of Overdose of Tadalafil

Home Delivery for Tadalafil in Your City

Medicine India is just a publishing medium for medicine related information and does not provide services or sales of medicines including tadalafil.

However, we do publish a comprehensive directory of Pharmacies, Chemists and Druggists in cities all over India. You can use this directory to find the medicine stores in your city (or area) that provide home delivery services for tadalafil and other medicines and health products. Home delivery services for tadalafil may be free or they may cost you depending on the pharmacy and the minimum order requirements. It would be best to get this clarified while placing the order.

Please be aware that you should take tadalafil only if a doctor has recommended or prescribed it. Some or all pharmacies who provide a home delivery service for medicines might insist on a prescription for tadalafil before they complete the sale. You can get this information while placing the order for tadalafil with the pharmacy.

Tadalafil is a generic medicine name and there are several brands available for it. Some of the brands for tadalafil might be better known than tadalafil itself. If the pharmacy that's willing to deliver medicines to your home doesn't have tadalafil in stock, you can ask for one of the branded alternatives for tadalafil.