Oxytocin / Tadalafil

Chewable Tablets

125 U / 25 mg

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Product Overview

Oxytocin Description1-6

Oxytocin is synthesized in the hypothalamus and stored in the posterior pituitary gland. A synthetic form of oxytocin is available and exhibits the same activity as the naturally occurring hormone. Oxytocin promotes contraction of uterine smooth muscle during labor and stimulates the alveolar ducts of the breast to release milk following its production. Due to its effects on uterine activity, oxytocin has been used to initiate labor, assist with placental delivery, and manage postpartum hemorrhage. Oxytocin has also been linked to social bonding, mood modulation, and sexual function.

Tadalafil Description7-9

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.

Oxytocin1-6

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.

Tadalafil7-9

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

  • Loss of appetite
  • Nausea, vomiting
  • Stomach pain.

Tadalafil

Common

  • Headache
  • Dyspepsia
  • Flushing
  • Back pain and myalgia (typically delayed onset, resolving within 48 hours)
  • Nasal congestion
  • Pain in limbs

Contraindications & Precautions1,2,7-9

Oxytocin

Contraindications

  • Known hypersensitivity to oxytocin
  • Pregnancy 1st or 2nd trimester

Precautions

  • Oxytocin may possess antidiuretic effects—extended administration may increase risk of fluid overload
  • Cardiovascular disease, due to oxytocin’s potential vasopressor effects

Tadalafil

Contraindications

  • Known hypersensitivity to tadalafil or tablet excipients
  • Use of nitrates and guanylate cyclase (GC) stimulators therapy, such as riociguat due to risk of life-threatening hypotension

Precautions

  • Use with caution in patients with:
    • Severe hepatic impairment (Child-Pugh Class C)
    • Severe renal impairment (creatinine clearance <30 mL/min)
    • Retinitis pigmentosa (rare inherited retinal disorder)
    • History of NAION (non-arteritic anterior ischemic optic neuropathy)
    • Recent history of myocardial infarction, stroke, or unstable angina
  • Store at controlled room temperature (20°C to 25°C / 68°F to 77°F)
  • Protect from moisture and light
  • Keep in a tightly closed container
  1. Oxytocin Prescribing Information – Fresenius Kabi. https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/018248s049lbl.pdf Revised September 2022. Accessed May 31, 2025
  2. Clinical Pharmacology Oxytocin clinical monograph 2025 https://www.clinicalkey.com/pharmacology/
  3. Osilla EV, Patel P, Sharma S. Oxytocin. [Updated 2025 Feb 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507848/
  4. Kou J, Lan C, Zhang Y, Wang Q, Zhou F, Zhao Z, Montag C, Yao S, Becker B, Kendrick KM. In the nose or on the tongue? Contrasting motivational effects of oral and intranasal oxytocin on arousal and reward during social processing. Transl Psychiatry. 2021 Feb 4;11(1):94.
  5. Zhuang Q, Zheng X, Yao S, Zhao W, Becker B, Xu X, Kendrick KM. Oral Administration of Oxytocin, Like Intranasal Administration, Decreases Top-Down Social Attention. Int J Neuropsychopharmacol. 2022 Nov 17;25(11):912-923.
  6. Quintana DS, Glaser BD, Kang H, Kildal ESM, Audunsdottir K, Sartorius AM, Barth C. The interplay of oxytocin and sex hormones. Neurosci Biobehav Rev. 2024 Aug;163:105765.
  7. Tadalafil Prescribing Information – Eli Lilly. www.accessdata.fda.gov/drugsatfda_docs/label/2011/021368s20s21lbl.pdf Revised October 2011. Accessed May 31, 2025
  8. Clinical Pharmacology Tadalafil clinical monograph 2025 https://www.clinicalkey.com/pharmacology/
  9. Padda IS, Tripp J. Phosphodiesterase Inhibitors. [Updated 2023 Jun 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK559276/

WPPL operates as a 503A compounding pharmacy and prepares individualized prescription medications pursuant to provider direction. Compounded preparations are not reviewed, tested, or approved by the FDA.

This listing also includes commercially manufactured products for convenience; these items are not compounded by our pharmacy and are sold as provided by their manufacturers. Actual products in stock at time of dispensing may vary due to supply chain variability. Any statements regarding non-compounded products are manufacturer-supplied, have not been evaluated by the FDA, and are not intended to diagnose, treat, cure, or prevent any disease. WPPL does not verify or endorse any therapeutic claims made by manufacturers. Please refer to original labeling for complete product information.

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