Dutasteride Contraindications is a synthetic 4-azasteroid compound. Dutasteride competitively and specifically binds to isoenzymes 1 and 2 of 5 alpha-reductase, forming stable enzyme complexes and inhibiting the conversion of testosterone to 5 alpha-dihydrotestosterone (DHT); the reduction in DHT activity may mitigate or prevent enlargement of the prostate gland. The type 2 5 alpha-reductase isoenzyme is primarily active in the reproductive tissues, while the type 1 isoenzyme is also active in skin and the liver.
Dutasteride, sold under the brand name Avodart among others, is a medication used primarily to treat enlarged prostate in men.[rx][rx][rx] It can also be used to treat scalp hair loss in men, excessive hair growth in women, and as a part of hormone therapy for transgender women.[rx][rx][rx][rx] It is taken by mouth.[rx]
Mechanism of Action of Dutasteride
Indications of Dutasteride
- For the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate gland to improve symptoms, and reduce the risk of acute urinary retention and the need for surgery.
- Scalp hair loss – Dutasteride is approved for the treatment of male androgenetic alopecia in South Korea and Japan at a dosage of 0.5 mg per day.[rx][rx] It has been found in several studies to improve hair growth in men more rapidly and to a greater extent than 2.5 mg/day finasteride.[rx] The superior effectiveness of dutasteride relative to finasteride for this indication is considered to be related to the fact that the inhibition of 5α-reductase and consequent prevention of scalp DHT production is more complete with dutasteride.[rx][rx] Dutasteride has also been used off-label in the treatment of female pattern hair loss.[rx]
- Excessive hair growth – Although no reports specific to dutasteride currently exist,[rx][rx] 5α-reductase inhibitors like finasteride have been found to be effective in the treatment of hirsutism (excessive facial and/or body hair growth) in women.[rx] In a study of 89 women with hyperandrogenism due to persistent adrenarche syndrome, finasteride produced a 93% reduction in facial hirsutism and a 73% reduction in bodily hirsutism after 2 years of treatment.[rx] Other studies using finasteride for hirsutism have also found it to be clearly effective.[rx] Dutasteride may be more effective than finasteride for this indication due to the fact that its inhibition of the 5α-reductase enzyme is comparatively more complete.[rx]
- Transgender hormone therapy- Dutasteride is sometimes used as a component of hormone therapy for transgender women in combination with an estrogen and/or another antiandrogen like spironolactone.[rx] It may be useful for treating scalp hair loss or in those who cannot tolerate spironolactone.[rx]
- Excessive hair growth- Although no reports specific to dutasteride currently exist,[rx][rx] 5α-reductase inhibitors like finasteride have been found to be effective in the treatment of hirsutism (excessive facial and/or body hair growth) in women.[rx] In a study of 89 women with hyperandrogenism due to persistent adrenarche syndrome, finasteride produced a 93% reduction in facial hirsutism and a 73% reduction in bodily hirsutism after 2 years of treatment.[rx] Other studies using finasteride for hirsutism have also found it to be clearly effective.[rx] Dutasteride may be more effective than finasteride for this indication due to the fact that its inhibition of the 5α-reductase enzyme is comparatively more complete.[rx]
- Transgender hormone therapy – Dutasteride is sometimes used as a component of hormone therapy for transgender women in combination with an estrogen and/or another antiandrogen like spironolactone.[rx] It may be useful for treating scalp hair loss or in those who cannot tolerate spironolactone.[rx]
Contraindications of Dutasteride
- Women who are or who may become pregnant should not handle the drug. Dutasteride can cause birth defects, specifically ambiguous genitalia and under masculinization, in male fetuses.[rx][rx] This is due to its antiandrogenic effects and is seen naturally in 5α-reductase deficiency.[rx]
- As such, women who are pregnant should never take dutasteride.[rx] People taking dutasteride should not donate blood to prevent birth defects if a pregnant woman receives blood and, due to its long elimination half-life, should also not donate blood for at least 6 months after the cessation of treatment.[rx]
- Children and people with known significant hypersensitivity (e.g., serious skin reactions, angioedema) to dutasteride should not take dutasteride.[rx]
- Liver problems
- Low Sperm Count
- Pregnancy
- A mother who is producing milk and breastfeeding
- High-Grade Prostate Cancer
Allergies to
- 5-Alfa Reductase Inhibitor
- Azasteroids
- Finasteride
- Dutasteride
Dosage of Dutasteride
Strengths: 0.5 mg
Benign Prostatic Hyperplasia
- 0.5 mg orally once a day
Side Effects of Dutasteride
The Most Common
- breast enlargement or tenderness
- decreased sexual desire or ability
- erectile dysfunction (difficulty getting or keeping an erection)
- rash, hives, or itching
- signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)
- sudden chest tightness
- swelling of the eyelids, face, lips
Common
- Chest pain or discomfort
- dilated neck veins
- extreme fatigue
- irregular breathing
- irregular heartbeat
- shortness of breath
- swelling of the face, fingers, feet, or lower legs
- weight gain
- wheezing
Rare
- Blistering, flaking, or peeling of the skin
- cough
- difficulty with swallowing
- dizziness
- fast heartbeat
- hives or welts
- itching skin
- large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
- puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
- redness of the skin
- skin rash
- tightness in the chest
- unusual tiredness or weakness
- wheezing
Drug Interactions of Dutasteride
Dutasteride may interact with following drugs, supplements & may change the efficacy of the drug
- “azole” antifungals (e.g., fluconazole, itraconazole, ketoconazole)
- allopregnanolone from progesterone and hence may reduce or block the sedative, anticonvulsant, anxiolytic, and various other effects of progesterone,
- boceprevir
- chloramphenicol
- cimetidine
- ciprofloxacin
- clarithromycin
- conivaptan
- cyclosporine
- delavirdine
- diltiazem
- grapefruit juice
- macrolide antibiotics (e.g., clarithromycin, erythromycin)
- nelfinavir
- nicardipine
- propranolol
- protease inhibitors (e.g., indinavir, ritonavir, saquinavir)
- St. John’s Wort
- verapamil
Pregnancy Category
AU TGA pregnancy category: X
US FDA pregnancy category: X
Pregnancy
This medication is intended for use by men only. Women who may be pregnant must avoid touching any pills of dutasteride (even ones that are not leaking). Pregnant women or women who may be pregnant should not handle dutasteride because the medication can be absorbed through the skin and may cause abnormalities in the baby. If a pregnant woman accidentally comes in contact with the capsules, she should wash the contact area immediately with soap and water.
Lactation
Dutasteride is not intended for use by women. It is not known if dutasteride passes into breast milk. Do not handle this medication if you are breastfeeding because the medication can be absorbed through the skin and may affect the baby. This medication is not intended for use by children. The safety and effectiveness of dutasteride have not been established for use by people in this age group.
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