Available Dosage Strengths
100 U / 5 mg
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Oxytocin Description1-8
Oxytocin is produced in the hypothalamus and stored in the posterior portion of the pituitary gland. Oxytocin is made synthetically and has activity identical to natural oxytocin. Oxytocin stimulates contraction of smooth muscle in the uterus during labor and stimulates the alveolar ducts to eject milk after it has been produced in the breast. Thus, because of the actions of oxytocin on the uterus, it has been used to induce labor, aid in the delivery of the placenta, and control postpartum bleeding. Oxytocin has also been associated with social bonding, mood regulation and sexual functioning.
Tadalafil Description
Tadalafil, a phosphodiesterase type 5 (PDE5) inhibitor, has a mean terminal half-life of over 17 hours. This half-life is much longer than other PDE-5 inhibitors. This half-life allows for once-daily or on-demand dosing. The drug is indicated for the treatment of pulmonary arterial hypertension (PAH), erectile dysfunction (ED), benign prostatic hypertrophy (BPH), or the concurrent treatment of ED and BPH.
Mechanism of Action1-9
Oxytocin
Oxytocin causes G-protein coupled receptors to increase intracellular calcium which leads to uterine contraction. The stimulation of uterine contractions causes more oxytocin to be released. As more oxytocin is released it positively influences even more release of oxytocin. This release of oxytocin is called positive feedback which is much different than how many hormones work in the endocrine system. Oxytocin administered exogenously causes the same response as endogenously produced oxytocin. Not only does oxytocin stimulate uterine contractions, but it also causes contractions of myoepithelial cells in the alveolar ducts found in female breast tissue. These contractions force milk from these ducts into even larger sinuses, which subsequently enables milk expulsion. When a baby attempts to latch onto the mother’s breast it causes oxytocin secretion into the blood in the same manner as vaginal delivery; instead of uterine contractions, milk is ejected from the breast. Similar to the actions of oxytocin in the uterus to stimulate contractions during delivery, milk-ejection from breast tissue occurs due to positive feedback. In the brain, it is proposed that oxytocin stimulates social and sexual function by its activity in many areas of the brain including its activity on neurotransmitters.
Tadalafil
Phosphodiesterase (PDE) has many isoforms and is an enzyme that has many functions in the body including degrading the effect of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). PDE5 is an enzyme that is found in many parts of the body including in the smooth muscle of the corpus cavernosum, prostate, bladder, the vascular and visceral smooth muscle, skeletal muscle, urethra, platelets, kidney, lung, cerebellum, heart, liver, testis, seminal vesicle, and pancreas. Tadalafil is a selective inhibitor of PDE5, the enzyme responsible for the degradation of cGMP. The drug has selective activity on PDE5 than other phosphodiesterase isoforms. Tadalafil activity on PDE5 is more than 10,000-fold more than for PDE1, PDE2, PDE4, and PDE7 enzymes. Increased cGMP leads to smooth muscle relaxation in the corpus cavernosum which can help in maintaining an erection.
Adverse Reactions1,2,7,8
Oxytocin
Common
Tadalafil
Common
Contraindications & Precautions1,2,7-9
Oxytocin
Contraindications
Precautions
Tadalafil
Contraindications
Precautions
Store at 20°C to 25°C (68°F to 77°F) in a cool, dry place.
This sheet is a summary. It may not cover all possible drug information about this product. Call your doctor for medical advice and/or about side effects. You may report side effects to the FDA at 1-800-FDA-1088. A Wells Pharmacy Network pharmacist will be happy to answer any questions. For consultation, please call 1-800-622-4510.
