Latanoprost

Latanoprost, an analog of prostaglandin F2alpha, is a prodrug used to reduce elevated intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension. Studies have shown that latanoprost administered once daily is at least as effective as timolol in lowering intraocular pressure.12 When latanoprost and timolol were used in combination, a complete or almost complete additive effect in reducing intraocular pressure has been observed.[24740] Treatment has been associated with increased pigmentation of the iris, periorbital tissue (eyelid) and eyelashes.[34

Finasteride

Finasteride is a 5-alpha reductase inhibitor used to treat symptomatic benign prostatic hyperplasia (BPH), a condition found in the majority of men over the age of 50. Finasteride has been shown to increase and maintain maximum urine flow rate in men with BPH, although less than 50% of men show improvement despite a reduction in prostate size. In a typical patient undergoing treatment for BPH with finasteride (>= 6 months), a 50% decrease in serum PSA concentrations can be expected; however, individual patients may experience varying decreases in PSA values. During treatment, serum PSA concentrations may decrease even in the presence of prostate cancer. If clinicians use serum PSA concentrations as an aid in the detection of prostate cancer in men receiving finasteride, values should be doubled for comparison with normal ranges in untreated men. Any increase from baseline, even if the value is within the normal range for untreated men, may signal the presence of prostate cancer. If clinicians elect to use percent free PSA (free to total PSA ratio) as a marker, no adjustment in PSA values appear to be necessary as the value is not significantly decreased by finasteride.5 In June 2011, a review of two large, randomized controlled trials, the Prostate Cancer Prevention Trial (PCPT) and the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial prompted the FDA to alert healthcare professionals of the potential risk of an increased incidence of high-grade prostate cancer in patients receiving finasteride or dutasteride treatment. Results from the PCPT trial showed that men receiving finasteride had a 26% decreased risk of being diagnosed with prostate cancer overall when compared to placebo (p < 0.0001); however, the risk reduction was limited to Gleason score (GS) <= 6 cancers. There was an increased incidence of GS 8—10 prostate cancers with finasteride compared to placebo (1.8% vs. 1.1%, respectively).67Finasteride is also used for hair restoration in men and has been shown to be effective for mild to moderate hair loss of the vertex and anterior mid-scalp area; efficacy in bitemporal recession has not been established. Finasteride (Proscar) was approved by the FDA in June 1992 for the treatment of BPH. Another finasteride oral dosage form, Propecia, was approved by the FDA in December 1997 for the treatment of male pattern baldness (i.e., androgenetic alopecia). Finasteride is also used investigationally as an alternative agent for treating hirsutism.

Latanoprost

Latanoprost is a selective agonist at a subtype of prostaglandin receptors known as the FP receptor. By acting on the FP receptor, latanoprost increases the outflow of aqueous humor thereby reducing intraocular pressure. According to the manufacturer, studies in both animals and man suggest that increased uveoscleral outflow is the primary mechanism of action.[34

Finasteride

Finasteride is a synthetic 4-aza analog of testosterone that acts as a competitive, specific inhibitor of type II 5-alpha-reductase, an intracellular enzyme that converts testosterone to the potent androgen 5-alpha-dihydrotestosterone (DHT). The type II 5alpha-reductase isozyme is primarily found in prostate, seminal vesicles, epididymides, and hair follicles, as well as liver. The type II isozyme is responsible for two-thirds of circulating DHT. DHT is the primary androgen that stimulates the development of prostate tissue. When used for the treatment of benign prostatic hyperplasia, as the enzymatic conversion from testosterone to DHT is inhibited, a desirable reduction in prostate hypertrophy is achieved, and urine flow should be improved. In male pattern hair loss, the balding scalp contains miniaturized hair follicles and increased amounts of DHT compared with hairy scalp. Finasteride decreases scalp and serum DHT concentrations, thus interrupting a key factor in the development of androgenetic alopecia in those patients genetically predisposed. Finasteride does not appear to affect circulating concentrations of cortisol, estradiol, prolactin, thyroid-stimulating hormone, thyroxine or cholesterol. Research to date also suggests that finasteride does not affect the hypothalamic-pituitary-testicular-axis.

Latanoprost

Latanoprost is administered topically to the eye as an isopropyl ester prodrug. Once in systemic circulation, the biologically active latanoprost acid is primarily metabolized by the liver to the 1,2-dinor and 1,2,3,4- tetranor metabolites via fatty acid beta-oxidation with an elimination half-life of 17 minutes. The metabolites are mainly eliminated by the kidneys, with 88% of the topically administered dose being recovered in the urine.[34

Finasteride

Finasteride is administered orally in the treatment of either BPH or male pattern baldness. Approximately 90% is bound to plasma proteins; yet the drug has been found to cross the blood-brain barrier. This is not problematic, since finasteride generally does not affect other hormones. Daily dosing causes accumulation to occur, with plasma concentrations increasing by 50% over those observed from a single dose. The mean plasma elimination half-life of finasteride is 4.8 to 6 hours (range, 3 to 16 hours); however, the turnover rate for the type II 5-alpha-reductase enzyme complex is slow, with a turnover half-life of approximately 30 days. After oral dosing, about half of the unchanged drug is excreted in the feces, and one-third is metabolized in the liver to the 17-carboxylic acid, which is then excreted in the urine (39%) and the feces (57%).

A single 5 mg oral dose rapidly reduces serum DHT concentrations by as much as 70%, with the maximum reduction occurring at about 8 hours. The effect lasts for at least 24 hours, so once daily dosing is appropriate. Actual clinical effects, however, are not realized for 3 to 6 months after beginning therapy.

Affected cytochrome P450(CYP450) isoenzymes and drug transporters: CYP3A4, UGT1A4

While finasteride is metabolized by hepatic CYP3A4 isoenzymes, no drug interactions of clinical importance have been identified, likely due to the hormonal mechanisms of action and relatively large therapeutic window of effect. Finasteride does not appear to affect the CYP450-linked drug metabolizing enzyme system. Compounds that have been tested in man have included antipyrine, digoxin, propranolol, theophylline, and warfarin and no clinically meaningful interactions were found. Finasteride has not been associated with clinically important drug interactions during clinical trials, including a 4-year safety trial of 3,040 males aged 45 to 78 years.89510 while finasteride markedly inhibited UGT1A4 activity in vitro in a drug transporter study; the data strongly suggested that finasteride is unlikely to cause clinically significant drug-drug interactions mediated via inhibition of the hepatic UGT enzymes involved in drug metabolism in vivo.

Latanoprost

Latanoprost should not be used in patients with closed-angle glaucoma, or inflammatory or neovascular glaucoma. There is limited experience with latanoprost in these patients.

Latanoprost should be used with caution in patients with aphakia, pseudophakic patients with a torn posterior lens capsule, and patients with known risk factors for macular edema. Macular edema, including cystoid macular edema, has been reported during treatment with this drug.[34

Recipients of latanoprost may experience a gradual increase in pigmentation (i.e., brown coloration) of the iris and periorbital tissue (eyelids), which may not be noticeable for several months to years. Patients who develop increased pigmentation may continue to receive treatment; however, these patients should be examined regularly as they may develop photophobia or be more sensitive to sunlight (UV) exposure. After discontinuing latanoprost, the change in iris color is likely to be permanent, while the pigmentation change in the periorbital tissue may be reversible in some patients. Eyelash changes (i.e., increased length, thickness, pigmentation, the number of lashes or hairs, and misdirected growth of eyelashes) has also been associated with the use of latanoprost. Eyelash changes are usually reversible upon treatment discontinuation. Inform drug recipients of the possibility of iridal and eyelid discoloration, and of the potential for eyelash changes.[34

Latanoprost should be used with caution in patients with active intraocular inflammation (e.g., iritis, uveitis). Use of latanoprost in these patient may exacerbate inflammation.[3 4

Instruct drug recipients to remove contact lenses before instilling latanoprost ophthalmic drops. Lenses may be reinserted 15 minutes after drug administration. The ophthalmic solution is formulated with the preservative benzalkonium chloride, which may be absorbed by soft contact lenses.[34

The use of multiple dose containers of ophthalmic products has been associated with bacterial keratitis. Inadvertent contamination of the latanoprost containers may increase the risk of infection in ocular surgery patients, or in patients who develop an ocular infection or ocular trauma, including corneal abrasion. If there is any damage to the ocular epithelial surface, latanoprost should be used with caution. Reactivation of herpes simplex keratitis has been reported during latanoprost therapy. Use caution in patients with a history of herpetic keratitis; avoid use in patients with active herpes simplex keratitis due to the potential for exacerbation of inflammation.[3

Latanoprost is classified as FDA pregnancy risk category C. Although there are no adequate and well-controlled studies in pregnant women, limited experience in human pregnancy has not resulted in clinically significant risk to the fetus. A minimal amount of drug reaches systemic circulation after ophthalmic administration, suggesting exposure of the drug to the fetus is low.11 According to the manufacturer, latanoprost should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.[3

According to the manufacturer, it is not known whether latanoprost or its metabolites are excreted in breast milk. Because systemic plasma concentrations of latanoprost are low and the half-life is short after ophthalmic administration, clinically significant amounts of the drug would not be expected to be excreted in breast-milk.11 To further minimize the amount of drug that reaches the systemic circulation and breast milk, apply pressure over the tear duct by the corner of the eye for 1 minute after ophthalmic administration. According to the manufacturer, caution should be exercised when latanoprost is administered during breast-feeding.[3 Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.

Safety and efficacy of latanoprost have not been established in the pediatric population (i.e., neonates, infants, children, or adolescents).[34

Latanoprost should be used cautiously in patients with renal disease (e.g., renal failure, renal impairment) or hepatic disease. There have been no studies on safe use in these patients.

Finasteride

Finasteride is not indicated for use in adolescents, children, or infants. Safety and effectiveness have not been established in pediatric patients under 18 years of age.510

Finasteride should be used with caution in patients with hepatic disease, since finasteride is metabolized extensively in the liver. Data are lacking regarding the incidence of adverse effects or drug accumulation in patients with hepatic impairment.

Finasteride reduces total serum prostate specific antigen (PSA). In a typical patient undergoing treatment for BPH with finasteride (>= 6 months), a 50% decrease in serum PSA concentrations can be expected; however, individual patients may experience varying decreases in PSA values. During treatment, serum PSA concentrations may decrease even in the presence of prostate cancer. If clinicians use serum PSA concentrations as an aid in the detection of prostate cancer in men receiving finasteride, values should be doubled for comparison with normal ranges in untreated men. Any increase from baseline, even if the value is within the normal range for untreated men, may signal the presence of prostate cancer. If clinicians elect to use percent free PSA (free to total PSA ratio) as a marker, no adjustment in PSA values appear to be necessary as the value is not significantly decreased by finasteride.5 In June 2011, a review of two large, randomized controlled trials, the Prostate Cancer Prevention Trial (PCPT) and the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) trial prompted the FDA to alert healthcare professionals of the potential risk of an increased incidence of high-grade prostate cancer in patients receiving finasteride or dutasteride treatment. Results from the PCPT trial showed that men receiving finasteride had a 26% decreased risk of being diagnosed with prostate cancer when compared to placebo (p < 0.0001); however, the risk reduction was limited to Gleason score (GS) <= 6 cancers. There was an increased incidence of GS 8—10 prostate cancers with finasteride compared to placebo (1.8% vs. 1.1%, respectively).67Therefore, in initiating or continuing treatment with finasteride, clinicians should weigh the known benefits of treatment against the potential risk and be aware that finasteride may increase the risk of high-grade prostate cancer. Further, lower urinary tract symptoms of BPH can be indicative of other urological diseases, including prostate cancer. Patients should be assessed to rule out other urological diseases prior to treatment with finasteride. Patients with a large residual urinary volume and/or severely diminished urinary flow may not be good candidates for 5-alpha-reductase inhibitor therapy and should be carefully monitored for urinary tract obstruction.5

Men treated with finasteride should refrain from blood donation while taking finasteride. The purpose of this is to prevent administration of finasteride to a pregnant female transfusion recipient.

Clinical efficacy studies of finasteride for hair loss did not include subjects aged 65 and over. Based on the pharmacokinetics of finasteride 5 mg, no dosage adjustment is necessary in the geriatric patient. However, the efficacy of finasteride for hair loss in the elderly has not been established.

The clinical significance of finasteride’s effect on semen characteristics for an individual male patient’s fertility is not known; consider the potential effects on semen when assessing a male with infertility. Finasteride may cause spermatogenesis inhibition or oligospermia, decreased sperm motility, or decreased semen volume. In a 52-week, randomized, double-blind, placebo-controlled study in healthy men, finasteride (5 mg PO once daily) significantly decreased total sperm count (-34.3%) compared to baseline at 26 weeks but not at 52 weeks or at the 24-week follow-up. Semen volume was decreased at 52 weeks for finasteride (-14.5%), but the effect was not statistically significant. Sperm concentration was decreased by finasteride (-7.4%) but was not significant for either drug. Significant reductions of 6 to 12% in sperm motility were observed during treatment. Sperm morphology was not affected. One subject taking finasteride had decreases in sperm count of more than 90% of baseline values at 52 weeks; partial recovery was noted at the 24-week follow-up. During post marketing surveillance, male infertility and/or poor seminal quality following treatment discontinuation have been reported. It should be noted that normalization or improvement of seminal quality has also been reported after discontinuation of finasteride.51012

Latanoprost

Latanoprost is classified as FDA pregnancy risk category C. Although there are no adequate and well-controlled studies in pregnant women, limited experience in human pregnancy has not resulted in clinically significant risk to the fetus. A minimal amount of drug reaches systemic circulation after ophthalmic administration, suggesting exposure of the drug to the fetus is low.11 According to the manufacturer, latanoprost should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.[3

Finasteride

Finasteride is not FDA-approved for use in females of childbearing potential and is contraindicated during pregnancy. Finasteride may cause fetal harm. Finasteride and other 5-alpha-reductase inhibitors, by inhibiting the conversion of testosterone to DHT, have the ability to cause abnormalities in the external genitalia of the male fetus. Pregnant women or females trying to conceive should not handle crushed or broken finasteride tablets. The distribution of finasteride into human semen has been assessed and appears to be well below the threshold concentration associated with fetal anomalies in animals.510

Latanoprost

According to the manufacturer, it is not known whether latanoprost or its metabolites are excreted in breast milk. Because systemic plasma concentrations of latanoprost are low and the half-life is short after ophthalmic administration, clinically significant amounts of the drug would not be expected to be excreted in breast-milk.11 To further minimize the amount of drug that reaches the systemic circulation and breast milk, apply pressure over the tear duct by the corner of the eye for 1 minute after ophthalmic administration. According to the manufacturer, caution should be exercised when latanoprost is administered during breast-feeding.[3 Consider the benefits of breast-feeding, the risk of potential infant drug exposure, and the risk of an untreated or inadequately treated condition. If a breast-feeding infant experiences an adverse effect related to a maternally ingested drug, healthcare providers are encouraged to report the adverse effect to the FDA.

Finasteride

Finasteride is not FDA-approved for use in females of childbearing potential and is recommended to be avoided during breast-feeding. It is not known whether finasteride is excreted in human milk. Therefore, the effects of finasteride on breast-feeding or a nursing infant cannot be determined.510

Latanoprost

Asthma or asthma exacerbations (bronchospasm) and dyspnea have been reported during postmarketing experience with latanoprost.[3

Infection (i.e., upper respiratory tract infection, naso-pharyngitis, influenza) was reported in 3% of patients receiving latanoprost during clinical trials. Cases of herpes keratitis have been reported with postmarketing use.[3

Postmarketing use of latanoprost has been associated with cases of palpitations, unstable angina, and chest pain (unspecified).[3

Myalgia, arthralgia, musculoskeletal pain, and back pain were reported in 1% of patients during latanoprost clinical trials.[3

Rash and other allergic skin reactions were reported at a rate of 1% during latanoprost clinical trials. Cases of pruritus and toxic epidermal necrolysis have been reported during postmarketing use of latanoprost.[3

Dizziness and headache have been reported during postmarketing experience with latanoprost.[3

Finasteride

Adverse reactions to finasteride are generally mild and transient. In a long-term (4 years) clinical trial in men with benign prostatic hypertrophy (BPH) [25064], the most frequently reported adverse reactions to finasteride were related to sexual function. At 1 year, the adverse reactions reported to be drug-related were impotence (erectile dysfunction), decreased libido, decreased ejaculate volume, ejaculation dysfunction, breast enlargement, breast tenderness (mastalgia), and rash (unspecified). There was no significant difference between finasteride and placebo in the incidences of impotence, decreased libido, and ejaculation dysfunction in years 2 to 4 of the study. However, during post marketing surveillance, continued erectile dysfunction, orgasm dysfunction or other orgasm disorders, and ejaculation dysfunction following treatment discontinuation have been reported.510 From June 1992, when finasteride was approved, until February 1995, the FDA received reports of gynecomastia in 214 men (median age: 71 yrs). Most were taking a dose of 5 mg/day PO. Gynecomastia has been the most frequently reported adverse effect of this drug since it was marketed. The onset of gynecomastia ranged from 14 days to 2.5 years (median: 180 days). Thirty percent had unilateral gynecomastia, 25% had bilateral involvement, and, in the remainder of reports, this information was not specified. Twenty-seven percent of patients were also taking other medications that are known to cause gynecomastia. Gynecomastia resolved either completely or partially in 80% of subjects after finasteride was discontinued, however, in at least 2 cases, a new primary malignancy of primary intraductal breast cancer subsequently developed.13 In a 4 to 6 year trial where patients were randomized to receive finasteride 5 mg/day, doxazosin 4 or 8 mg/day, a combination of the two drugs, or placebo, four patients reported breast cancer as an adverse experience; three of the patients were receiving finasteride therapy and one patient was receiving combination therapy. In addition, male breast cancer has been reported during post-marketing experience. Other post-marketing adverse reactions have included depression, testicular pain that continued after discontinuation of treatment, and hypersensitivity reactions including pruritus, urticaria, and angioedema (including swelling of the lips, tongue, throat, and face).5

In controlled trials of finasteride for the treatment of male pattern hair loss, 1.4% of patients discontinued therapy due to adverse events, compared with 1.6% of placebo-treated patients. Discontinuation of therapy because of a drug-related sexual adverse experience occurred in 1.2% of patients on finasteride and 0.9% of patients on placebo. The following adverse events were reported as at least possibly drug-related in finasteride-treated patients: libido decrease (1.8%), impotence (1.3%), and ejaculation disorder (1.2%), primarily decreased ejaculate volume. The incidence of each of the above adverse effects decreased to <= 0.3% by the fifth year of treatment. During post marketing surveillance, decreased libido and libido disorders that continued after discontinuation of treatment was reported.5

Finasteride may cause spermatogenesis inhibition or oligospermia, decreased sperm motility, or decreased semen volume. The clinical significance of finasteride’s effect on semen characteristics for an individual male patient’s fertility is not known; consider the potential effects on semen when assessing a male with infertility. In a 52-week, randomized, double-blind, placebo-controlled study in healthy men, finasteride (5 mg PO once daily) significantly decreased total sperm count (-34.3%) compared to baseline at 26 weeks but not at 52 weeks or at the 24-week follow-up. Semen volume was decreased at 52 weeks for finasteride (-14.5%), but the effect was not statistically significant. Sperm concentration was decreased by finasteride (-7.4%) but was not significant for either drug. Significant reductions of 6 to 12% in sperm motility were observed during treatment. Sperm morphology was not affected. One subject taking finasteride had decreases in sperm count of more than 90% of baseline values at 52 weeks; partial recovery was noted at the 24-week follow-up. During post marketing surveillance, male infertility and/or poor seminal quality following treatment discontinuation have been reported. It should be noted that normalization or improvement of seminal quality has also been reported after discontinuation of finasteride.51012

By inhibiting the conversion of testosterone to DHT, finasteride and other 5-alpha-reductase inhibitors have the ability to cause teratogenesis, specifically abnormalities in the external genitalia of the male fetus (e.g., hypospadias).5

Store this medication in a refrigerator between 36°F to 46°F (2°C – 8°C). Do not freeze. Protect from light. Keep all medicine out of the reach of children. Throw away any medicine after the beyond use date. Do not flush unused medications or pour down a sink or drain.