Viagra online in Australia

Use

Therapeutic indications

VIAGRA is indicated for adult men with erectile dysfunction, which is the inability to achieve or maintain an erection of the penis suficient for satisfactory sexual activity.

Sexual stimulation is required for VIAGRA to be effective.

Dosage and method of administration

Dose

Use in adults:

The recommended dose is 50 mg taken as needed, approximately one hour before any sexual activity. Depending on the efficacy and tolerance, the dose can be increased to 100 mg or reduced to 25 mg. The maximum recommended dose is 100 mg. The maximum frequency of use is once a day.

If the medicine is taken with food, the action of VIAGRA may be delayed compared to taking it on an empty stomach (see section Pharmacokinetic properties).

Special populations

Elderly

No dose adjustment is required in the elderly (≥ 65 years of age).

Renal insufficiency

The dosage recommendations described in the paragraph "Use in adults" apply to patients with mild to moderate renal impairment (creatinine clearance = 30 to 80 ml / min).

Since sildenafil clearance decreases in patients with severe renal impairment (creatinine clearance minus 30 ml / min), use of a 25 mg dose should be considered. Depending on the efficacy and tolerance, the dose can be gradually increased to 50 mg and up to 100 mg, if necessary.

Liver failure

Since the clearance of sildenafil decreases in patients with hepatic impairment (eg, Cirrhosis), the use of a 25 mg dose should be considered. Depending on the efficacy and tolerance, the dose can be gradually increased to 50 mg and up to 100 mg, if necessary.

Pediatric population

VIAGRA is not indicated for people under 18 years of age.

Use in patients taking other medications.

Excluding ritonavir for which the combination is not recomended (see section 4.4), the use of a starting dose of 25 mg should be considered in patients receiving concomitant treatment with CYP3A4 inhibitors (see section Interactions with other medicinal products and other forms of interaction) .

To minimize the possible occurrence of orthostatic hypotension in patients receiving alpha-blocker therapy, patients receiving alpha-blocker therapy should be stabilized before starting sildenafil treatment. In addition, consideration should be given to initiating treatment with sildenafil at a dose of 25 mg (see sections 4.4 and 4.4).

Administration form

Oral use.

Prescription and delivery conditions

List I.

Duration and special precautions for conservation

Conversation duration:

5 years.

Special precautions for storage:

Store at a temperature not exceeding + 30 ° C.

Store in the original container to protect it from moisture.

Preclinical safety data

Non-clinical data from conventional studies of safety pharmacology, repeated-dose toxicology, genotoxicity, carcinogenesis, and reproductive and developmental functions did not reveal any particular risk to humans.

Incompatibilities

Aimlessly.

Employment precautions

Contraindications

Hypersensitivity to the active substance or to any of the excipients included in the Composition section.

Given the knowledge of its mode of action in the pathway of nitrogen monoxide / cyclic guanosine monophosphate (cGMP) (see section Pharmacodynamic properties), an enhancement of the hypotensive effects of nitrates by sildenafil has been demonstrated; Therefore, its concomitant administration with nitric oxide donors (such as amyl nitrite) or with nitrates in any form is contraindicated.

Co-administration of PDE5 inhibitors, such as sildenafil, with guanylate cyclase stimulators, such as riociguat, is contraindicated due to the risk of symptomatic hypotension (see section Interactions with other medicinal products and other forms of interaction)

Medicines used to treat erectile dysfunction, including sildenafil, should not be used in men for whom sexual activity is not recommended (for example, patients with severe cardiovascular disorders such as unstable angina or severe heart failure).

VIAGRA is contraindicated in patients with vision loss in one eye due to non-arteritic anterior ischemic optic neuropathy (NAION), whether or not this event has been asociated with prior exposure to a PDE5 inhibitor (see Warnings and Precautions for Use section). ).

The safety of sildenafil has not been studied in the following patient subgroups: severe liver failure, hypotension (blood pressure minus 90/50 mmHg), recent history of stroke or myocardial infarction, and known inherited degenerative disorders of the retina, such as retinitis pigmentosa (a minority of these patients have genetic disorders of retinal phosphodiesterases).

Pregnancy and lactation

VIAGRA is not indicated for women.

There have been no adequate and adequately controlled studies in pregnant or lactating women.

In reproductive studies in rats and rabbits, no relevant side effects were observed after oral administration of sildenafil.

There was no effect on sperm motility or morphology after oral administration of a single 100 mg dose of sildenafil in healthy volunteers (see Pharmacodynamic properties section).

Warnings and precautions for use

A history and clinical examination will be performed to diagnose erectile dysfunction and determine its possible underlying cause before considering medication.

Cardiovascular risk factors.

Before starting treatment for erectile dysfunction, physicians should examine the cardiovascular function of their patients, as any sexual activity carries a cardiac risk. Sildenafil has vasodilatory properties that result in transient and slight decreases in blood pressure (see Pharmacodynamic properties section). Before prescribing sildenafil, doctors should carefully assess the potential risk in patients who may have certain underlying conditions affected by these vasodilatory effects, especially during sexual activity. Patients with increased sensitivity to vasodilators are those who have an obstacle to left ventricular ejection (eg, aortic stenosis, obstructive hypertrophic cardiomyopathy), or the rare syndrome of multiple system atrophy, which manifests as severe insufficiency of the autonomous control of blood pressure.

VIAGRA enhances the hypotensive effects of nitrates (see Contraindications section).

Since its comercialization, serious cardiovascular events such as myocardial infarction, unstable angina, sudden cardiac death, ventricular arrhythmia, cerebrovascular hemorrhage, transient ischemic attack, hypertension and hypotension have been reported with the use of VIAGRA Most, but not all, of these patients they had pre-existing cardiovascular risk factors. Many events have been reported to occur during or shortly after intercourse and some were reported to occur after the use of VIAGRA without sexual activity. It is not possible to determine if these events are directly related to these or other factors.

Priapism

Medicines to treat erectile dysfunction, including sildenafil, should be used with caution in patients with an anatomical deformation of the penis (such as angulation, sclerosis of the corpora cavernosa or Peyronie's disease) or in patients presenting pathologies that may predispose them to priapism (such as sickle cell anemia, multiple myeloma or leukemia).

Prolonged erections and priapism have been reported in post-marketing experience in patients receiving sildenafil. If an erection lasts more than 4 hours, the patient should seek medical help immediately. If priapism is not treated right away, it can lead to damage to penile tissue and permanent impotence.

Concomitant use with other PDE5 inhibitors or other treatments for erectile dysfunction

The safety and efficacy of combining sildenafil with other PDE5 inhibitors, other treatments for pulmonary arterial hypertension (PAH) containing sildenafil (REVATIO), or other treatments for erectile dysfunction have not been studied. Therefore, it is not recommended to use such associations.

Effects on vision.

Visual abnormalities have been reported spontaneously after the use of sildenafil and other PDE5 inhibitors (see section 4.8). Non-arteritic anterior ischemic optic neuropathy, a rare disease, was reported spontaneously in an observational study after the use of sildenafil and other PDE5 inhibitors (see section 4.8).

Patients should be advised that, in case of any sudden visual abnormality, they should stop taking VIAGRA and seek immediate medical attention (see section 4.3).

Concomitant use of ritonavir

Concomitant administration of sildenafil and ritonavir is not recommended (see section Interactions with other medicinal products and other forms of interaction).

Concomitant use of alpha blockers

Caution is recommended when administering sildenafil to patients taking an alpha-blocker, as co-administration may cause symptomatic hypotension in a small number of susceptible subjects (see Interactions with other medicinal products and other forms of interactions). This occurs more frequently within 4 hours after taking sildenafil. In order to minimize the possible occurrence of orthostatic hypotension, patients on alpha-blockers should be hemodynamically stable before starting sildenafil treatment. The initiation of treatment with a dose of 25 mg should be considered (see section 4.2). Additionally, physicians should advise their patients what to do in case of symptoms of orthostatic hypotension.

Effect on bleeding

Studies in human blood platelets show that sildenafil enhances the antiplatelet effect of sodium nitropruside in vitro. There are no data on the safety of sildenafil in patients with bleeding disorders or active peptic ulcer. Therefore, sildenafil should only be administered to these patients after careful evaluation of the risk-benefit balance.

The film coating of the VIAGRA tablet contains lactose. Therefore, VIAGRA should not be used in patients with hereditary galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption.

Women

VIAGRA is not indicated for women.

Interaction with other medicinal products and other forms of interaction

Effects of other medicinal products on sildenafil

In vitro studies

Sildenafil is metabolized mainly by isoenzymes 3A4 (main route) and 2C9 (secondary route) of cytochrome P450 (CYP). Therefore, inhibitors of these isoenzymes can decrease sildenafil clearance and inducers of these isoenzymes can increase sildenafil clearance.

In vivo studies

Population pharmacokinetic analysis of clinical trial data has shown a decreased clearance of sildenafil when co-administered with CYP3A4 inhibitors (such as ketoconazole, erythromycin, cimetidine). Although the incidence of side effects has not been increased in these patients, when co-administered with sildenafil and CYP3A4 inhibitors, a starting dose of 25 mg should be considered.

Co-administration of 100 mg single-dose sildenafil and ritonavir antiprotease, a very potent steady-state cytochrome P 450 inhibitor (500 mg twice daily), produced a 300% (4-fold) increase in Cmax. sildenafil and a 1000% (11-fold) increase in AUC for sildenafil. After 24 hours, the plasma concentrations of sildenafil were still approximately 200 ng / ml, while they were approximately 5 ng / ml when sildenafil alone was administered. This is consistent with the marked effects of ritonavir on a large number of P 450 cytochrome substrates. Sildenafil has no effect on ritonavir pharmacokinetics. In view of these pharmacokinetic results, concomitant administration of sildenafil and ritonavir is not recommended (see section 4.4), and in no case should the maximum sildenafil dose exceed 25 mg in 48 hours.

Concomitant administration of 100 mg sildenafil as a single dose with saquinavir antiprotease, a CYP3A4 inhibitor, at steady state (1200 mg three times daily) resulted in a 140% increase in Cmax. of sildenafil and a 210% increase in AUC of sildenafil. Sildenafil has no effect on the pharmacokinetics of saquinavir (see section 4.2). We can expect to see more marked effects with potent CYP3A4 inhibitors such as ketoconazole and itraconazole.

A 182% increase in systemic exposure to sildenafil (AUC) was observed when taking a single 100 mg dose of sildenafil with erythromycin (moderate CYP3A4 inhibitor) balance (500 mg twice daily for 5 days). In healthy male volunteers, no effect of azithromycin (500 mg daily for 3 days) was observed on AUC, Cmax, tmax, constant elimination rate, or the half-life of sildenafil or its major circulating metabolite. Co-administration of sildenafil (50 mg) and cimetidine (800 mg), a cytochrome P450 inhibitor, and a non-specific CYP3A4 inhibitor, resulted in a 56% increase in plasma sildenafil concentrations in healthy volunteers.

Grapefruit juice is a weak inhibitor of CYP3A4-mediated metabolism in the intestinal wall and may slightly increase plasma concentrations of sildenafil.

Antacids (magnesium hydroxide / aluminum hydroxide) in single doses have no effect on the bioavailability of sildenafil.

Although specific interaction studies have not been performed for all medicinal products, population pharmacokinetic analysis has shown that co-administration of substances from the CYP2C9 group of inhibitors (such as tolbutamide, warfarin, phenytoin) or CYP2D6 (as specific inhibitors of serotonin reuptake, tricyclic antidepresants), thiazides and related diuretics, loop diuretics and potassium preservatives, angiotensin converting enzyme inhibitors, calcium channel blockers, beta-adrenergic receptor blockers, or metabolism inducers

CYP 450 mediated (such as rifampin and barbiturates), had no effect on the pharmacokinetics of sildenafil. In a study in healthy male volunteers, concomitant administration of the endothelin antagonist bosentan (a moderate inducer of CYP3A4, CYP2C9 and possibly CYP2C19) at steady state (125 mg twice daily) and sildenafil at steady state (80 mg three times a day) resulted in a 62.6% and 55.4% decrease in sildenafil AUC and Cmax respectively. Therefore, co-administration of potent CYP3A4 inducers, such as rifampicin, is expected to lead to further decreases in plasma concentrations of sildenafil.

Nicorandil is a hybrid of potassium channel activator and nitro derivative. Due to the nitro derived component, it can cause severe interaction with sildenafil.

Sildenafil effects on other medicines.

In vitro studies

Sildenafil is a weak inhibitor of isoenzymes 1A2, 2C9, 2C19, 2D6, 2E1 and 3A4 (IC50 plus 150 (rM) of cytochrome P 450. The maximum plasma concentration of sildenafil is approximately 1 (rM after dosing administration. VIAGRA is unlikely to affect the removal of substrates for these isoenzymes.

No interaction data are available between sildenafil and nonspecific phosphodiesterase inhibitors, such as theophylline or dipyridamole.

In vivo studies

Given the knowledge of its mode of action at the level of the nitric oxide / cGMP pathway (see section Pharmacodynamic properties), an enhancement of the hypotensive effects of nitrate derivatives by sildenafil has been demonstrated; therefore, its concomitant administration with nitric oxide donors or nitro derivatives in any form is contraindicated (see section Contraindications).

Riociguat

Preclinical studies have shown an increase in the systemic hypotensive effect when PDE5 inhibitors were combined with riociguat. In clinical studies, riociguat has been shown to increase the hypotensive effects of PDE5 inhibitors. No benefit of association has been demonstrated in the study population. Concomitant use of riociguat with PDE5 inhibitors, such as sildenafil, is contraindicated (see section 4.3).

Concomitant administration of sildenafil to patients taking alpha-blocker therapy may cause symptomatic hypotension in a small number of susceptible individuals. This occurs most frequently within 4 hours after taking sildenafil (see sections 4.2 and 4.4 and Warnings and precautions for use). In three specific drug interaction studies, alpha-blockers doxazosin (4 mg and 8 mg) and sildenafil (25 mg, 50 mg or 100 mg) were administered simultaneously in patients with benign prostatic hyperplasia (BPH) stabilized under doxazosin treatment. In the populations of these studies, additional mean reductions in standing blood presure of 7/7 mmHg, 9/5 mmHg, and 8/4 mmHg and additional mean reductions in standing blood pressure of 6/6 mmHg, 11 were observed. / 4 mmHg and 4/5 mmHg, respectively. When sildenafil and doxazosin were co-administered to patients stabilized with doxazosin therapy, rare reports of patients with symptomatic orthostatic hypotension were observed. These reports included dizziness and intoxicating sensations, but not fainting.

No significant interaction was observed when co-administered with sildenafil (50 mg) and tolbutamide (250 mg) or warfarin (40 mg), two substances metabolized by CYP2C9.

Sildenafil (50 mg) does not potentiate the lengthening of bleeding time induced by acetylsalicylic acid (150 mg).

Sildenafil (50 mg) does not potentiate the hypotensive effect of alcohol in healthy volunteers with an average maximum blood alcohol concentration of 80 mg / dl.

Compared to placebo, there was no difference in the safety profile in patients taking sildenafil in combination with one of the following clases of antihypertensives: diuretics, beta-blockers, ACE inhibitors, angiotensin II inhibitors, vasodilators, action antihypertensives. central, adrenergic antagonists, calcium channel blockers and alpha blockers. In a specific interaction study where sildenafil (100 mg) was administered with amlodipine in hypertensive patients, a further decrease in systolic blood pressure of 8 mmHg was observed while lying down. The corresponding decrease in diastolic blood pressure was 7 mmHg while lying down. These additional reductions in blood pressure were similar to those observed when sildenafil was administered only to healthy volunteers (see section Pharmacodynamic properties).

Sildenafil (100 mg) does not affect the steady-state pharmacokinetics of saquinavir and ritonavir, two CYP3A4 antiprotease substrates.

In healthy male volunteers, sildenafil at steady state (80 mg three times daily) resulted in a 49.8% increase in AUC for bosentan and a 42% increase in Cmax for bosentan (125 mg twice daily). .

Caution

Undesirable effects

Sumary of the safety profile

VIAGRA's safety profile is based on 9,570 patients from 74 double-blind, placebo-controlled clinical trials. The most common adverse reactions reported in clinical trials among sildenafil-treated patients were headache, rednes, dyspepsia, nasal congestion, dizziness, nausea, redness, visual disturbances, cyanopsy, and blurred vision.

Adverse reactions reported during post-market surveillance refer to an estimated period of more than 10 years. The frequencies of these effects cannot be reliably determined as not all undesirable effects are reported to the Marketing Authorization Holder and included in the tolerance database.

Table of adverse reactions.

In the table below, all clinically important undesirable effects that have appeared during clinical trials with a higher incidence than placebo are listed by organ system classes and by frequency (very common (≥ 1/10), Common (≥ 1/100 and less than 1/10), uncommon (≥1 / 1000 and less than 1/100), rare (≥ 1/10000 and less than 1/1000) .Side effects should be presented in descending order of gravity.

Table 1: Clinically important adverse reactions reported with a higher incidence than placebo in controlled clinical trials and clinically important adverse reactions reported during post-marketing surveillance.

Organ systems class

Very

frequent

(≥1 / 10)

Frequent

(≥ 1/100,

minus 1/10)

Rare

(≥ 1/1000,

minus 1/100)

Rare (≥ 1 / 10,000,

minus 1/1000)

Infections and infestations.

Rhinitis

Affects of

system

imune

Hypersensitivity

Affects of

nervous system

Headache

Sensations

dizziness

Drowsiness

Hypoesthesia

Stroke, accident

transient ischemic

Epilepsy crisis *,

Crisis recurrence

epilepsy *, syncope

Ailments

eyepieces

Impaired color vision **, visual disturbance, blurred vision

problems

***,

Eye pain

Photophobia,

Photopsia,

Hyperemia

ocular

Intensification of

brightness

Conjunctivitis

Non-arteritic anterior ischemic optic neuropathy

(NOIAN) *, retinal vascular occlusion *,

Retinal hemorrhage, retinopathy of arteriosclerotic origin, retinal disorder, glaucoma, alteration

visual field, Diplopia, Decreased

visual acuity, myopia,

Asthenopia, floating bodies of the vitreous, iris anomaly, mydriasis, Halos vision, edema

eye, eye swelling, problems

ocular, hyperemia

conjunctival

Eye irritation, abnormal sensations in the eyes, eyelid edema,

Scleral discoloration

Conditions of

ear and labyrinth

Dizziness

Tinnitus

Deafness

Ailments

heart

Tachycardia,

Palpitations

Sudden cardiac death *, myocardial infarction,

Arrhythmia

ventricular *,

Fibrillation

handset

Unstable angina

Ailments

vascular

Redness

Hot flushes

Hypertension,

Hypotension

Respiratory, thoracic and mediastinal disorders.

Congestion

nasal

Epistaxis,

Congestion

breast

Sensation of

constriction of

pharynx, edema

nasal dryness

nasal

Gastrointestinal disorders.

intestinal

Sickness

Dyspepsia

Gastroesophageal reflux disease, vomiting, pain

high abdomen, dry mouth

Oral hypoesthesia

Terms

skin and subcutaneous tissue

Eruption

Stevens-Johnson syndrome (SJS) *,

Lyell syndrome *

Ailments

muscle

skeletal and systemic

Myalgia, pain

extremities

Kidney conditions

and shapes

urinary

Hematuria

Reproductive system and breast disorders.

Bleeding from the penis,

Priapism *,

Hematospermia,

Increased erection

General disorders

and anomalies in the administration site

Pain

Chest, fatigue, feeling

hot

Irritability

Research

Acceleration of the heart beat.

* Only reported during post-marketing surveillance

** Impaired color vision: chloropsia, chromatopsia, cyanopsy, erythropsy and xanthopsia.

*** Tear disorders: dry eyes, tear disorder and increased tear discharge.

Notification of suspected adverse reactions.

Notification of suspected adverse reactions after authorization of the medicinal product is important. Allows continuous monitoring of the benefit / risk ratio of the drug. Health professionals are requested to report any suspected adverse reactions through the national reporting system listed in Appendix V.

Overdose

- In studies in volunteers who received single doses of up to 800 mg, the side effects were the same as for lower doses, but their incidence and severity increased. The 200 mg doses do not provide greater efficacy, but increased the incidence of adverse effects (headache, redness of the face, dizziness, dyspepsia, nasal congestion, blurred vision).

- In case of overdose, the usual symptomatic treatment measures should be implemented as necessary. Kidney dialysis should not accelerate the elimination of sildenafil, which is strongly bound to plasma proteins and is not excreted in the urine.