Staxyn

Uses

Staxyn is used to treat erectile dysfunction (ED).

Staxyn is also used to associated treatment for these conditions: Erectile Dysfunction

How Staxyn works

Staxyn inhibits the cGMP specific phosphodiesterase type 5 (PDE5) which is responsible for degradation of cGMP in the corpus cavernosum located around the penis. Penile erection during sexual stimulation is caused by increased penile blood flow resulting from the relaxation of penile arteries and corpus cavernosal smooth muscle. This response is mediated by the release of nitric oxide (NO) from nerve terminals and endothelial cells, which stimulates the synthesis of cGMP in smooth muscle cells. Cyclic GMP causes smooth muscle relaxation and increased blood flow into the corpus cavernosum. The inhibition of phosphodiesterase type 5 (PDE5) by vardenafil enhances erectile function by increasing the amount of cGMP.

Dosage

Staxyn dosage

Initial dose: 10 mg orally once a day, as needed, approximately 60 minutes before sexual activity. Increase to 20 mg or decrease to 5 mg based on efficacy and tolerability.

Maximum dose: 20 mg once a day

Usual Geriatric Dose for Erectile Dysfunction (65 years or older): 5 mg orally once a day, as needed, approximately 60 minutes before sexual activity

Patients on stable alpha blocker therapy: 5 mg orally once a day

Side Effects

Dyspepsia, vomiting, headache, flushing, dizziness, visual disturbances, colour vision changes, raised intra-ocular pressure, nasal congestion, hypersensitivity reactions, nausea, photosensitivity reactions, hypotension, hypertension, priapism, palpitations, myalgia, increased creatinine kinase, sudden decrease or loss of hearing, tinnitus.

Toxicity

Symptoms of overdose include vision changes and back and muscle pain.

Precaution

Safety and efficacy have not been established in patients younger than 18 years. This drug is not indicated for use in pediatric patients.

Interaction

Increased risk of hypotension with α-blockers. Increased risk of priapism with alprostadil. Increased serum levels of vardenafil when used with erythromycin.

Food Interaction

• Avoid grapefruit products. Staxyn is metabolized by CYP3A4, and grapefruit products are CYP3A4 inhibitors; therefore, coadministration may increase serum levels of vardenafil and result in increased hypotension. .
• Take with or without food.

[Moderate] MONITOR: Grapefruit juice may increase the plasma concentrations of orally administered drugs that are substrates of the CYP450 3A4 isoenzyme.

The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruit.

Because grapefruit juice inhibits primarily intestinal rather than hepatic CYP450 3A4, the magnitude of interaction is greatest for those drugs that undergo significant presystemic metabolism by CYP450 3A4 (i.e., drugs with low oral bioavailability).

In general, the effect of grapefruit juice is concentration-, dose- and preparation-dependent, and can vary widely among brands.

Certain preparations of grapefruit juice (e.g., high dose, double strength) have sometimes demonstrated potent inhibition of CYP450 3A4, while other preparations (e.g., low dose, single strength) have typically demonstrated moderate inhibition.

Pharmacokinetic interactions involving grapefruit juice are also subject to a high degree of interpatient variability, thus the extent to which a given patient may be affected is difficult to predict.

MANAGEMENT: Patients who regularly consume grapefruit or grapefruit juice should be monitored for adverse effects and altered plasma concentrations of drugs that undergo significant presystemic metabolism by CYP450 3A4.

Grapefruit and grapefruit juice should be avoided if an interaction is suspected.

Orange juice is not expected to interact with these drugs.

Staxyn Alcohol interaction

[Moderate] GENERALLY AVOID:

Additive hypotensive effects may occur when phosphodiesterase-5 (PDE5) inhibitors are used with alcohol, as both are mild systemic vasodilators.

In clinical pharmacology studies, more subjects administered alcohol at a dose of 0.7 g/kg (equivalent to approximately 6 ounces of 80-proof vodka in an 80-kg male; consumed within 10 minutes in study subjects, providing blood alcohol levels of 0.08%) in combination with tadalafil 10 or 20 mg single doses had clinically significant decreases in blood pressure than with alcohol alone.

There were reports of postural dizziness, and orthostatic hypotension was observed in some.

When tadalafil 20 mg was administered with alcohol at a lower dose of 0.6 g/kg (equivalent to approximately 4 ounces of 80-proof vodka in an 80-kg male), orthostatic hypotension was not observed, dizziness occurred with similar frequency relative to alcohol alone, and the hypotensive effects of alcohol were not potentiated.

Neither tadalafil nor alcohol affected the plasma concentrations of the other.

Administration of avanafil 200 mg with alcohol at a dose of 0.5 g/kg (equivalent to approximately 3 ounces of 80-proof vodka in a 70-kg male; consumed within 15 minutes in study subjects, providing blood alcohol levels of 0.057%) resulted in additional maximum supine systolic/diastolic blood pressure decreases of 3.5/4.5 mm Hg and additional maximum pulse rate increase of 9.3 bpm compared to alcohol alone, but did not cause orthostatic hypotension or dizziness.

The plasma concentrations of alcohol were not affected.

Sildenafil 50 mg and vardenafil 20 mg reportedly did not potentiate the hypotensive effect of alcohol in healthy volunteers with mean maximum blood alcohol levels of 0.08% and in healthy volunteers administered alcohol at a dose of 0.5 g/kg, respectively.

Alcohol and vardenafil plasma levels were not altered when dosed simultaneously.

Patients taking PDE5 inhibitors should avoid consuming large amounts of alcohol, which may increase the potential for orthostatic signs and symptoms including increase in heart rate, decrease in standing blood pressure, dizziness, and headache.

Staxyn Drug Interaction

Major: tadalafil, sildenafilModerate: arginine, lithium, metoprolol, metoprololUnknown: zolpidem, aspirin, aspirin, diphenhydramine, celecoxib, ubiquinone, omega-3 polyunsaturated fatty acids, cyclobenzaprine, acetaminophen, acetaminophen / oxycodone, clopidogrel, cyanocobalamin, ascorbic acid, cholecalciferol

Staxyn Disease Interaction

Major: cardiovascular disease, renal dysfunction, QT prolongationModerate: priapism, alcoholism, hearing loss, retinitis pigmentosa, seizure disorders, liver disease, PKU

Volume of Distribution

• 208 L

Elimination Route

Staxyn is rapidly absorbed with absolute bioavailability of approximately 15%.

Half Life

4-5 hours

Clearance

• 56 L/h

Elimination Route

After oral administration, vardenafil is excreted as metabolites predominantly in the feces (approximately 91-95% of administered oral dose) and to a lesser extent in the urine (approximately 2-6% of administered oral dose).

Pregnancy & Breastfeeding use

Pregnancy Category B: Either animal-reproduction studies have not demonstrated a foetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the 1st trimester (and there is no evidence of a risk in later trimesters).

Contraindication

Known prolongation of QT interval (congenital or acquired); men for whom sexual intercourse is inadvisable due to CV risk factors; hypotension (systolic 170 mm Hg or diastolic >110 mm Hg); recent stroke or MI (within last 6 mth); unstable angina; severe heart failure; end-stage renal disease requiring dialysis; severe hepatic impairment; known degenerative retinal disorders e.g. retinitis pigmentosa. Women, child.

Special Warning

Patients stabilised on α-blocker therapy: max daily dose 5 mg and not to be taken within 6 hr of the α-blocker (except tamsulosin). Patients on erythromycin: Max: 5 mg daily.Renal Impairment: Haemodialysis: Avoid.Hepatic Impairment:

• Child Pugh A-B (mild to moderate) impairment: Initiate with 5 mg.
• Max dose in moderate impairment: 10 mg.
• Child-Pugh C (severe impairment): No studies done.

Storage Condition

Store between 15-30° C.

Innovators Monograph

You find simplified version here Staxyn