- dapoxetine hydrochloride
POM: Prescription only medicine
This information is intended for use by health professionals
Adult men (aged 18 to 64 years)The recommended starting dose for all patients is 30 mg, taken as needed approximately 1 to 3 hours prior to sexual activity. Treatment with Priligy should not be initiated with the 60 mg dose.Priligy is not intended for continuous daily use. Priligy should be taken only when sexual activity is anticipated. Priligy must not be taken more frequently than once every 24 hours.If the individual response to 30 mg is insufficient and the patient has not experienced moderate or severe adverse reactions or prodromal symptoms suggestive of syncope, the dose may be increased to a maximum recommended dose of 60 mg taken as needed approximately 1 to 3 hours prior to sexual activity. The incidence and severity of adverse events is higher with the 60 mg dose.If the patient experienced orthostatic reactions on the starting dose, no dose escalation to 60 mg should be performed (see section 4.4).A careful appraisal of individual benefit risk of Priligy should be performed by the physician after the first four weeks of treatment (or at least after 6 doses of treatment) to determine whether continuing treatment with Priligy is appropriate.Data regarding the efficacy and safety of Priligy beyond 24 weeks are limited. The clinical need of continuing and the benefit risk balance of treatment with Priligy should be re-evaluated at least every six months.
Elderly (age 65 years and over)The efficacy and safety of Priligy have not been established in patients age 65 years and over (see section 5.2).
Paediatric populationThere is no relevant use of Priligy in this population in the indication of premature ejaculation.
Patients with renal impairmentCaution is advised in patients with mild or moderate renal impairment. Priligy is not recommended for use in patients with severe renal impairment (see sections 4.4 and 5.2).
Patients with hepatic impairmentPriligy is contraindicated in patients with moderate and severe hepatic impairment (Child−Pugh Class B and C) (see sections 4.3 and 5.2).
Known CYP2D6 poor metabolizers or patients treated with potent CYP2D6 inhibitorsCaution is advised if increasing the dose to 60 mg in patients known to be of CYP2D6 poor metabolizer genotype or in patients concomitantly treated with potent CYP2D6 inhibitors (see sections 4.4, 4.5 and 5.2).
Patients treated with moderate or potent inhibitors of CYP3A4Concomitant use of potent CYP3A4 inhibitors is contraindicated. The dose should be restricted to 30 mg in patients concomitantly treated with moderate CYP3A4 inhibitors and caution is advised (see sections 4.3, 4.4 and 4.5).
Method of administrationFor oral use. Tablets should be swallowed whole to avoid the bitter taste. It is recommended that tablets be taken with at least one full glass of water. Priligy may be taken with or without food (see section 5.2).
Precautions to be taken before handling or administering the medicinal productBefore treatment is initiated, see section 4.4 regarding orthostatic hypotension.
General recommendationsPriligy is only indicated in men with Premature Ejaculation who meet all the criteria listed in sections 4.1 and 5.1. Priligy should not be prescribed to men who have not been diagnosed with Premature Ejaculation. Safety has not been established and there are no data on the ejaculation−delaying effects in men without Premature Ejaculation.
Other forms of sexual dysfunctionBefore treatment, subjects with other forms of sexual dysfunction, including erectile dysfunction, should be carefully investigated by physicians. Priligy should not be used in men with erectile dysfunction (ED) who are using PDE5 inhibitors (see section 4.5).
Orthostatic hypotensionBefore treatment initiation, a careful medical examination including history of orthostatic events should be performed by the physician. An orthostatic test should be performed before initiating therapy (blood pressure and pulse rate, supine and standing). In case of a history of documented or suspected orthostatic reaction, treatment with Priligy should be avoided.Orthostatic hypotension has been reported in clinical trials. The prescriber should counsel the patient in advance that if he experiences possibly prodromal symptoms, such as lightheadedness soon after standing, he should immediately lie down so his head is lower than the rest of his body or sit down with his head between his knees until the symptoms pass. The prescriber should also inform the patient not to rise quickly after prolonged lying or sitting.
Suicide/suicidal thoughtsAntidepressants, including SSRIs, increased the risk compared to placebo of suicidal thinking and suicidality in short-term studies in children and adolescents with Major Depressive Disorder and other psychiatric disorders. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24. In clinical trials with Priligy for the treatment of premature ejaculation, there was no clear indication of treatment-emergent suicidality in evaluation of possibly suicide-related adverse events evaluated by the Columbia Classification Algorhythm of Suicide Assessment (C-CASA), Montgomery-Asberg Depression Rating Scale, or Beck Depression Inventory-II.
SyncopePatients should be cautioned to avoid situations where injury could result, including driving or operating hazardous machinery, should syncope or its prodromal symptoms such as dizziness or lightheadedness occur (see section 4.8).Possibly prodromal symptoms such as nausea, dizziness/lightheadedness, and diaphoresis were reported more frequently among patients treated with Priligy compared to placebo. In the clinical trials, cases of syncope characterized as loss of consciousness, with bradycardia or sinus arrest observed in patients wearing Holter monitors,were considered vasovagal in etiology and the majority occurred during the first 3 hours after dosing, after the first dose, or associated with study−related procedures in the clinic setting (such as blood draw and orthostatic maneuvers and blood pressure measurements). Possibly prodromal symptoms, such as nausea, dizziness, lightheadedness, palpitations, asthenia, confusion and diaphoresis generally occurred within the first 3 hours following dosing, and often preceded the syncope. Patients need to be made aware that they could experience syncope at any time with or without prodromal symptoms during their treatment with Priligy. Prescribers should counsel patients about the importance of maintaining adequate hydration and about how to recognize prodromal signs and symptoms to decrease the likelihood of serious injury associated with falls due to loss of consciousness. If the patient experiences possibly prodromal symptoms, the patient should immediately lie down so his head is lower than the rest of his body or sit down with his head between his knees until the symptoms pass, and be cautioned to avoid situations where injury could result, including driving or operating hazardous machinery, should syncope or other CNS effects occur (see section 4.7).
Patients with cardiovascular risk factorsSubjects with underlying cardiovascular disease were excluded from Phase 3 clinical trials. The risk of adverse cardiovascular outcomes from syncope (cardiac syncope and syncope from other causes) is increased in patients with underlying structural cardiovascular disease (e.g., documented outflow obstruction, valvular heart disease, carotid stenosis and coronary artery disease). There are insufficient data to determine whether this increased risk extends to vasovagal syncope in patients with underlying cardiovascular disease.
Use with recreational drugsPatients should be advised not to use Priligy in combination with recreational drugs.Recreational drugs with serotonergic activity such as ketamine, methylenedioxymethamphetamine (MDMA) and lysergic acid diethylamide (LSD) may lead to potentially serious reactions if combined with Priligy. These reactions include, but are not limited to, arrhythmia, hyperthermia, and serotonin syndrome. Use of Priligy with recreational drugs with sedative properties such as narcotics and benzodiazepines may further increase somnolence and dizziness.
EthanolPatients should be advised not to use Priligy in combination with alcohol.Combining alcohol with dapoxetine may increase alcohol−related neurocognitive effects and may also enhance neurocardiogenic adverse events such as syncope, thereby increasing the risk of accidental injury; therefore, patients should be advised to avoid alcohol while taking Priligy (see sections 4.5 and 4.7).
Medicinal products with vasodilatation propertiesPriligy should be prescribed with caution in patients taking medicinal products with vasodilatation properties (such as alpha adrenergic receptor antagonists and nitrates) due to possible reduced orthostatic tolerance (see section 4.5).
Moderate CYP3A4 inhibitorsCaution is advised in patients taking moderate CYP3A4 inhibitors and the dose is restricted to 30 mg (see sections 4.2 and 4.5).
Potent CYP2D6 inhibitorsCaution is advised if increasing the dose to 60 mg in patients taking potent CYP2D6 inhibitors or if increasing the dose to 60 mg in patients known to be of CYP2D6 poor metabolizer genotype, as this may increase exposure levels, which may result in a higher incidence and severity of dose dependent adverse events (see sections 4.2, 4.5 and 5.2).
ManiaPriligy should not be used in patients with a history of mania/hypomania or bipolar disorder and should be discontinued in any patient who develops symptoms of these disorders.
SeizureDue to the potential of SSRIs to lower the seizure threshold, Priligy should be discontinued in any patient who develops seizures and avoided in patients with unstable epilepsy. Patients with controlled epilepsy should be carefully monitored.
Paediatric populationPriligy should not be used in individuals below 18 years of age.
Depression and/or psychiatric disordersMen with underlying signs and symptoms of depression should be evaluated prior to treatment with Priligy to rule out undiagnosed depressive disorders. Concomitant treatment of Priligy with antidepressants, including SSRIs and SNRIs, is contraindicated (see section 4.3). Discontinuation of treatment for ongoing depression or anxiety in order to initiate Priligy for the treatment of PE is not recommended. Priligy is not indicated for psychiatric disorders and should not be used in men with these disorders, such as schizophrenia, or in those suffering with co−morbid depression, as worsening of symptoms associated with depression cannot be excluded. This could be the result of underlying psychiatric disorder or might be a result of medicinal product therapy. Physicians should encourage patients to report any distressing thoughts or feelings at any time and if signs and symptoms of depression develop during treatment, Priligy should be discontinued.
HaemorrhageThere have been reports of bleeding abnormalities with SSRIs. Caution is advised in patients taking Priligy, particularly in concomitant use with medicinal products known to affect platelet function (e.g., atypical antipsychotics and phenothiazines, acetylsalicylic acid, nonsteroidal anti−inflammatory drugs [NSAIDs], anti−platelet agents) or anticoagulants (e.g., warfarin), as well as in patients with a history of bleeding or coagulation disorders (see section 4.5).
Renal impairmentPriligy is not recommended for use in patients with severe renal impairment and caution is advised in patients with mild or moderate renal impairment (see sections 4.2 and 5.2).
Withdrawal effectsAbrupt discontinuation of chronically administered SSRIs used to treat chronic depressive disorders has been reported to result in the following symptoms: dysphoric mood, irritability, agitation, dizziness, sensory disturbances (e.g., paresthesias such as electric shock sensations), anxiety, confusion, headache, lethargy, emotional lability, insomnia and hypomania.A double−blind clinical trial in subjects with PE designed to assess the withdrawal effects of 62 days of daily or as needed dosing with 60 mg Priligy showed mild withdrawal symptoms with a slightly higher incidence of insomnia and dizziness in subjects switched to placebo after daily dosing (see section 5.1).
Eye disordersThe use of Priligy has been associated with ocular effects such as mydriasis and eye pain. Priligy should be used with caution in patients with raised intraocular pressure or those at risk of angle closure glaucoma.
Lactose intolerancePatients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose−galactose malabsorption should not take this medicine.
Potential for interaction with monoamine oxidase inhibitorsIn patients receiving an SSRI in combination with a monoamine oxidase inhibitor (MAOI), there have been reports of serious, sometimes fatal, reactions including hyperthermia, rigidity, myoclonus, autonomic instability with possible rapid fluctuations of vital signs, and mental status changes that include extreme agitation progressing to delirium and coma. These reactions have also been reported in patients who have recently discontinued an SSRI and have been started on an MAOI. Some cases presented with features resembling neuroleptic malignant syndrome. Animal data on the effects of combined use of an SSRI and MAOIs suggest that these medicinal products may act synergistically to elevate blood pressure and evoke behavioural excitation. Therefore, Priligy should not be used in combination with an MAOI, or within 14 days of discontinuing treatment with an MAOI. Similarly, an MAOI should not be administered within 7 days after Priligy has been discontinued (see section 4.3).
Potential for interaction with thioridazineThioridazine administration alone produces prolongation of the QTc interval, which is associated with serious ventricular arrhythmias. Medicinal products such as Priligy that inhibit the CYP2D6 isoenzyme appear to inhibit the metabolism of thioridazine and the resulting elevated levels of thioridazine are expected to augment the prolongation of the QTc interval. Priligy should not be used in combination with thioridazine or within 14 days of discontinuing treatment with thioridazine. Similarly, thioridazine should not be administered within 7 days after Priligy has been discontinued (see section 4.3).
Medicinal/herbal products with serotonergic effectsAs with other SSRIs, co−administration with serotonergic medicinal/herbal products (including MAOIs, L−tryptophan, triptans, tramadol, linezolid, SSRIs, SNRIs, lithium and St. John's Wort (Hypericum perforatum) preparations) may lead to an incidence of serotonin associated effects. Priligy should not be used in combination with other SSRIs, MAOIs or other serotonergic medicinal/herbal products or within 14 days of discontinuing treatment with these medicinal/herbal products. Similarly, these medicinal/herbal products should not be administered within 7 days after Priligy has been discontinued (see section 4.3).CNS active medicinal productsThe use of Priligy in combination with CNS active medicinal products (e.g., antiepileptics, antidepressants, antipsychotics, anxiolytics, sedative hypnotics) has not been systematically evaluated in patients with premature ejaculation. Consequently, caution is advised if the concomitant administration of Priligy and such medicinal products is required.
Effects of co−administered medicinal products on the pharmacokinetics of dapoxetineIn vitro studies in human liver, kidney, and intestinal microsomes indicate dapoxetine is metabolized primarily by CYP2D6, CYP3A4 and flavin monooxygenase 1 (FMO1). Therefore, inhibitors of these enzymes may reduce dapoxetine clearance.
CYP3A4 inhibitorsPotent CYP3A4 inhibitors. Administration of ketoconazole (200 mg twice daily for 7 days) increased the Cmax and AUCinf of dapoxetine (60 mg single dose) by 35% and 99%, respectively. Considering the contribution of both unbound dapoxetine and desmethyldapoxetine, the Cmax of the active fraction may be increased by approximately 25% and the AUC of the active fraction may be doubled if taken with potent CYP3A4 inhibitors.The increases in the Cmax and AUC of the active fraction may be markedly increased in a part of the population which lack a functional CYP2D6 enzyme, i.e., CYP2D6 poor metabolizers, or in combination with potent inhibitors of CYP2D6. Therefore, concomitant use of Priligy and potent CYP3A4 inhibitors, such as ketoconazole, itraconazole, ritonavir, saquinavir, telithromycin, nefazodone, nelfinavir and atazanavir, is contraindicated (see section 4.3).Moderate CYP3A4 inhibitors. Concomitant treatment with moderate CYP3A4 inhibitors (e.g., erythromycin, clarithromycin, fluconazole, amprenavir, fosamprenavir, aprepitant, verapamil, diltiazem) may also give rise to significantly increased exposure of dapoxetine and desmethyldapoxetine, especially in CYP2D6 poor metabolizers. The maximum dose of dapoxetine should be 30 mg if dapoxetine is combined with any of these drugs (see sections 4.2, 4.4 and below).These two measures apply to all patients unless the patient has been verified to be a CYP2D6 extensive metabolizer by geno− or phenotyping. In patients verified to be CYP2D6 extensive metabolizers, a maximum dose of 30 mg is advised if dapoxetine is combined with a potent CYP3A4 inhibitor and caution is advised if dapoxetine in 60 mg doses is taken concomitantly with a moderate CYP3A4 inhibitor.
Potent CYP2D6 inhibitorsThe Cmax and AUCinf of dapoxetine (60 mg single dose) increased by 50% and 88%, respectively, in the presence of fluoxetine (60 mg/day for 7 days). Considering the contribution of both unbound dapoxetine and desmethyldapoxetine, the Cmax of the active fraction may be increased by approximately 50% and the AUC of the active fraction may be doubled if taken with potent CYP2D6 inhibitors. These increases in the Cmax and AUC of the active fraction are similar to those expected for CYP2D6 poor metabolizers and may result in a higher incidence and severity of dose dependent adverse events (see section 4.4).PDE5 inhibitorsPriligy should not be used in patients using PDE5 inhibitors due to possible reduced orthostatic tolerance (see section 4.4). The pharmacokinetics of dapoxetine (60 mg) in combination with tadalafil (20 mg) and sildenafil (100 mg) were evaluated in a single dose crossover study. Tadalafil did not affect the pharmacokinetics of dapoxetine. Sildenafil caused slight changes in dapoxetine pharmacokinetics (22% increase in AUCinf and 4% increase in Cmax), which are not expected to be clinically significant.Concomitant use of Priligy with PDE5 inhibitors may result in orthostatic hypotension (see section 4.4). The efficacy and safety of Priligy in patients with both premature ejaculation and erectile dysfunction concomitantly treated with Priligy and PDE5 inhibitors have not been established.
Effects of dapoxetine on the pharmacokinetics of co −administered medicinal products
TamsulosinConcomitant administration of single or multiple doses of 30 mg or 60 mg dapoxetine to patients receiving daily doses of tamsulosin did not result in changes in the pharmacokinetics of tamsulosin. The addition of dapoxetine to tamsulosin did not result in a change in the orthostatic profile and there were no differences in orthostatic effects between tamsulosin combined with either 30 or 60 mg dapoxetine and tamsulosin alone; however, Priligy should be prescribed with caution in patients who use alpha adrenergic receptor antagonists due to possible reduced orthostatic tolerance (see section 4.4).
Medicinal products metabolized by CYP2D6Multiple doses of dapoxetine (60 mg/day for 6 days) followed by a single 50 mg dose of desipramine increased the mean Cmax and AUCinf of desipramine by approximately 11% and 19%, respectively, compared to desipramine administered alone. Dapoxetine may give rise to a similar increase in the plasma concentrations of other drugs metabolized by CYP2D6. The clinical relevance is likely to be small.
Medicinal products metabolized by CYP3A4Multiple dosing of dapoxetine (60 mg/day for 6 days) decreased the AUCinf of midazolam (8 mg single dose) by approximately 20% (range −60 to +18%). The clinical relevance of the effect on midazolam is likely to be small in most patients. The increase in CYP3A activity may be of clinical relevance in some individuals concomitantly treated with a medicinal product mainly metabolized by CYP3A and with a narrow therapeutic window.
Medicinal products metabolized by CYP2C19Multiple dosing of dapoxetine (60 mg/day for 6 days) did not inhibit the metabolism of a single 40 mg dose of omeprazole. Dapoxetine is unlikely to affect the pharmacokinetics of other CYP2C19 substrates.
Medicinal products metabolized by CYP2C9Multiple dosing of dapoxetine (60 mg/day for 6 days) did not affect the pharmacokinetics or pharmacodynamics of a single 5 mg dose of glyburide. Dapoxetine is unlikely to affect the pharmacokinetics of other CYP2C9 substrates.
Warfarin and medicinal products that are known to affect coagulation and/or platelet functionThere are no data evaluating the effect of chronic use of warfarin with dapoxetine; therefore, caution is advised when dapoxetine is used in patients taking warfarin chronically (see section 4.4). In a pharmacokinetic study, dapoxetine (60 mg/day for 6 days) did not affect the pharmacokinetics or pharmacodynamics (PT or INR) of warfarin following a single 25 mg dose.There have been reports of bleeding abnormalities with SSRIs (see section 4.4).
EthanolCoadministration of a single dose of ethanol, 0.5 g/kg (approximately 2 drinks), did not affect the pharmacokinetics of dapoxetine (60 mg single dose); however, dapoxetine in combination with ethanol increased somnolence and significantly decreased self−rated alertness. Pharmacodynamic measures of cognitive impairment (Digit Vigilance Speed, Digit Symbol Substitution Test) also showed an additive effect when dapoxetine was coadministered with ethanol. Concomitant use of alcohol and dapoxetine increases the chance or severity of adverse reactions such as dizziness, drowsiness, slow reflexes, or altered judgment. Combining alcohol with dapoxetine may increase these alcohol−related effects and may also enhance neurocardiogenic adverse events such as syncope, thereby increasing the risk of accidental injury; therefore, patients should be advised to avoid alcohol while taking Priligy (see sections 4.4 and 4.7).
Summary of the safety profileSyncope and orthostatic hypotension have been reported in clinical trials (see section 4.4).The following adverse drug reactions were reported during Phase 3 clinical trials most commonly and were dose related: nausea (11.0% and 22.2% in 30 mg and 60 mg prn dapoxetine groups, respectively), dizziness (5.8% and 10.9%), headache (5.6% and 8.8%), diarrhoea (3.5% and 6.9%), insomnia (2.1% and 3.9%) and fatigue (2.0% and 4.1%). The most common adverse events leading to discontinuation were nausea (2.2% of Priligy−treated subjects) and dizziness (1.2% of Priligy−treated subjects).
Tabulated list of adverse reactionsThe safety of Priligy was evaluated in 4224 subjects with premature ejaculation who participated in five double−blind, placebo−controlled clinical trials. Of the 4224 subjects, 1616 received Priligy 30 mg as needed and 2608 received 60 mg, either as needed or once daily.Table 1 presents the adverse reactions that have been reported.
|Table 1: Frequency of Adverse Reactions (MedDRA)|
|System Organ Class||Very common (> 1/10)||Common ( ≥ 1/100 to < 1/10)||Uncommon ( ≥ 1/1000 to < 1/100)||Rare ( ≥ 1/10000 to < 1/1000)|
|Psychiatric disorders||Anxiety, Agitation, Restlessness, Insomnia, Abnormal dreams, Libido decreased||Depression, Depressed mood, Euphoric mood, Mood altered, Nervousness, Indifference, Apathy, Confusional state, Disorientation, Thinking abnormal, Hypervigilance, Sleep disorder, Initial insomnia, Middle insomnia, Nightmare, Bruxism, Loss of libido, Anorgasmia|
|Nervous system disorders||Dizziness, Headache||Somnolence, Disturbance in attention, Tremor, Paraesthesia||Syncope, Syncope vasovagal, Dizziness postural, Akathisia, Dysgeusia, Hypersomnia, Lethargy, Sedation, Depressed level of consciousness||Dizziness exertional, Sudden onset of sleep|
|Eye disorders||Vision blurred||Mydriasis (see section 4.4), Eye pain, Visual disturbance|
|Ear and labyrinth disorders||Tinnitus||Vertigo|
|Cardiac disorders||Sinus arrest, Sinus bradycardia, Tachycardia|
|Vascular disorders||Flushing||Hypotension, Systolic hypertension, Hot flush|
|Respiratory, thoracic and mediastinal disorders||Sinus congestion, Yawning|
|Gastrointestinal disorders||Nausea||Diarrhoea, Vomiting, Constipation, Abdominal pain, Abdominal pain upper, Dyspepsia, Flatulence, Stomach discomfort, Abdominal distension, Dry mouth||Abdominal discomfort, Epigastric discomfort||Defaecation urgency|
|Skin and subcutaneous tissue disorders||Hyperhidrosis||Pruritis, Cold sweat|
|Reproductive system and breast disorders||Erectile dysfunction||Ejaculation failure, Male orgasmic disorder, Paraesthesia of genital male|
|General disorders and administration site conditions||Fatigue, Irritability||Asthenia, Feeling hot, Feeling jittery, Feeling abnormal, Feeling drunk|
|Investigations||Blood pressure increased||Heart rate increased, Blood pressure diastolic increased, Blood pressure orthostatic increased|
Description of selected adverse reactionsSyncope characterized as loss of consciousness, with bradycardia or sinus arrest observed in patients wearing Holter monitors, has been reported in clinical trials and is considered medicinal product-related. The majority of cases occurred during the first 3 hours after dosing, after the first dose or associated with study-related procedures in the clinical setting (such as blood draw and orthostatic maneuvers and blood pressure measurements). Prodromal symptoms often preceded the syncope (see section 4.4).The occurrence of syncope and possibly prodromal symptoms appears dose dependent as demonstrated by higher incidence among patients treated with higher than recommended doses in Phase 3 clinical trials.Orthostatic hypotension has been reported in clinical trials (see section 4.4).The frequency of syncope characterized as loss of consciousness in the Priligy clinical development program varied depending on the population studied and ranged from 0.06% (30 mg) to 0.23% (60 mg) for subjects enrolled in the Phase 3 placebo-controlled clinical trials to 0.64% (all doses combined) for Phase 1 non-PE healthy volunteer studies.
Other special populationsCaution is advised if increasing the dose to 60 mg in patients taking potent CYP2D6 inhibitors or if increasing the dose to 60 mg in patients known to be of CYP2D6 poor metabolizer genotype (see sections 4.2, 4.4, 4.5 and 5.2).
Withdrawal effectsAbrupt discontinuation of chronically administered SSRIs used to treat chronic depressive disorders has been reported to result in the following symptoms: dysphoric mood, irritability, agitation, dizziness, sensory disturbances (e.g., paresthesias such as electric shock sensations), anxiety, confusion, headache, lethargy, emotional lability, insomnia and hypomania.Results of a safety study showed a slightly higher incidence of withdrawal symptoms of mild or moderate insomnia and dizziness in subjects switched to placebo after 62 days of daily dosing. Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme. Website: www.mhra.gov.uk/yellowcard.
Mechanism of actionDapoxetine is a potent selective serotonin reuptake inhibitor (SSRI) with an IC50 of 1.12 nM, while its major human metabolites, desmethyldapoxetine (IC50 < 1.0 nM) and didesmethyldapoxetine (IC50 = 2.0 nM) are equivalent or less potent (dapoxetine-N-oxide (IC50 = 282 nM)).Human ejaculation is primarily mediated by the sympathetic nervous system. The ejaculatory pathway originates from a spinal reflex centre, mediated by the brain stem, which is influenced initially by a number of nuclei in the brain (medial preoptic and paraventricular nuclei).The mechanism of action of dapoxetine in premature ejaculation is presumed to be linked to the inhibition of neuronal reuptake of serotonin and the subsequent potentiation of the neurotransmitter's action at pre− and postsynaptic receptors.In the rat, dapoxetine inhibits the ejaculatory expulsion reflex by acting at a supraspinal level within the lateral paragigantocellular nucleus (LPGi). Post ganglionic sympathetic fibers that innervate the seminal vesicles, vas deferens, prostate, bulbourethral muscles and bladder neck cause them to contract in a coordinated fashion to achieve ejaculation. Dapoxetine modulates this ejaculatory reflex in rats.
Clinical efficacy and safetyThe effectiveness of Priligy in the treatment of premature ejaculation has been established in five double−blind, placebo−controlled clinical trials, in which a total of 6081 subjects were randomized. Subjects were 18 years of age or older and had a history of PE in the majority of intercourse experiences in the 6−month period prior to enrolment. Premature ejaculation was defined according to the DSM-IV diagnostic criteria: short ejaculatory time (an intravaginal ejaculatory latency time [IELT; time from vaginal penetration to the moment of intravaginal ejaculation] of ≤ 2 minutes measured using a stopwatch in four studies), poor control over ejaculation, marked distress or interpersonal difficulty due to the condition.Subjects with other forms of sexual dysfunction, including erectile dysfunction, or those using other forms of pharmacotherapy for the treatment of PE were excluded from all studies.Results of all randomized studies were consistent. Efficacy was demonstrated after 12 weeks of treatment. One study enrolled patients both outside and within the EU and had a treatment duration of 24 weeks. In the study, 1162 subjects were randomized, 385 to placebo, 388 to Priligy 30 mg as needed, and 389 to Priligy 60 mg as needed. The mean and median Average IELT at study end are presented in Table 2 below and the cumulative distribution of subjects who achieved at least a specific level in Average IELT at study end are presented in Table 3 below. Other studies and pooled analysis of the data at Week 12 gave consistent results.
|Table 2: Least squares mean and median Average IELT at study end*|
|Average IELT||Placebo||Priligy 30 mg||Priligy 60 mg|
|Median||1.05 min||1.72 min||1.91 min|
|Difference from placebo [95% CI]||0.6 min** [0.37, 0.72]||0.9 min** [0.66, 1.06]|
|Least Squares Mean||1.7 min||2.9 min||3.3 min|
|Difference from placebo [95% CI]||1.2 min** [0.59, 1.72]||1.6 min** [1.02, 2.16]|
|*Baseline value carried forward for subjects with no post-baseline data. **Difference was statistically significant (p-value <= 0.001).|
|Table 3: Subjects achieving at least a specific level in Average IELT at study end*|
|IELT (mins)||Placebo %||Priligy 30 mg %||Priligy 60 mg %|
|* Baseline value carried forward for subjects with no post-baseline data.|
AbsorptionDapoxetine is rapidly absorbed with maximum plasma concentrations (Cmax) occurring approximately 1-2 hours after tablet intake. The absolute bioavailability is 42% (range 15−76%), and dose proportional increases in exposure (AUC and Cmax) are observed between the 30 and 60 mg dose strengths. Following multiple doses, AUC values for both dapoxetine and the active metabolite desmethyldapoxetine (DED) increase by approximately 50% when compared to single dose AUC values.Ingestion of a high fat meal modestly reduced the Cmax (by 10%) and modestly increased the AUC (by 12%) of dapoxetine and slightly delayed the time for dapoxetine to reach peak concentrations. These changes are not clinically significant. Priligy can be taken with or without food.
DistributionMore than 99% of dapoxetine is bound in vitro to human serum proteins. The active metabolite desmethyldapoxetine (DED) is 98.5% protein bound. Dapoxetine has a mean steady state volume of distribution of 162 L.
BiotransformationIn vitro studies suggest that dapoxetine is cleared by multiple enzyme systems in the liver and kidneys, primarily CYP2D6, CYP3A4, and flavin monooxygenase (FMO1). Following oral dosing of 14C−dapoxetine, dapoxetine was extensively metabolized to multiple metabolites primarily through the following biotransformational pathways: N−oxidation, N−demethylation, naphthyl hydroxylation, glucuronidation and sulfation. There was evidence of presystemic first−pass metabolism after oral administration.Intact dapoxetine and dapoxetine−N−oxide were the major circulating moieties in the plasma. In vitro binding and transporter studies show that dapoxetine−N−oxide is inactive. Additional metabolites including desmethyldapoxetine and didesmethyldapoxetine account for less than 3% of the total circulating drug related materials in plasma. In vitro binding studies indicate that DED is equipotent to dapoxetine and didesmethyldapoxetine has approximately 50% of the potency of dapoxetine (see section 5.1). The unbound exposures (AUC and Cmax) of DED are approximately 50% and 23%, respectively, of the unbound exposure of dapoxetine.
EliminationThe metabolites of dapoxetine were primarily eliminated in the urine as conjugates. Unchanged active substance was not detected in the urine. Following oral administration, dapoxetine has an initial (disposition) half-life of approximately 1.5 hours, with plasma levels less than 5% of peak concentrations by 24 hours post-dose, and a terminal half-life of approximately 19 hours. The terminal half−life of DED is approximately 19 hours.
Pharmacokinetics in special populationsThe metabolite DED contributes to the pharmacological effect of Priligy, particularly when the exposure of DED is increased. Below, in some populations, the increase in active fraction parameters is presented. This is the sum of the unbound exposure of dapoxetine and DED. DED is equipotent to dapoxetine. The estimation assumes equal distribution of DED to the CNS but it is unknown whether this is the case.
RaceAnalyses of single dose clinical pharmacology studies using 60 mg dapoxetine indicated no statistically significant differences between Caucasians, Blacks, Hispanics and Asians. A clinical study conducted to compare the pharmacokinetics of dapoxetine in Japanese and Caucasian subjects showed 10% to 20% higher plasma levels (AUC and peak concentration) of dapoxetine in Japanese subjects due to lower body weight. The slightly higher exposure is not expected to have a meaningful clinical effect.
Elderly (age 65 years and over)Analyses of a single dose clinical pharmacology study using 60 mg dapoxetine showed no significant differences in pharmacokinetic parameters (Cmax, AUCinf, Tmax) between healthy elderly males and healthy young adult males. The efficacy and safety has not been established in this population (see section 4.2).
Renal impairmentA single-dose clinical pharmacology study using a 60 mg dapoxetine dose was conducted in subjects with mild (CrCL 50 to 80 mL/min), moderate (CrCL 30 to < 50 mL/min), and severe renal impairment (CrCL < 30 mL/min) and in subjects with normal renal function (CrCL > 80 mL/min). No clear trend for an increase in dapoxetine AUC with decreasing renal function was observed. AUC in subjects with severe renal impairment was approximately 2-fold that of subjects with normal renal function, although there are limited data in patients with severe renal impairment. Dapoxetine pharmacokinetics have not been evaluated in patients requiring renal dialysis (see sections 4.2 and 4.4).
Hepatic impairmentIn patients with mild hepatic impairment, unbound Cmax of dapoxetine is decreased by 28% and unbound AUC is unchanged. The unbound Cmax and AUC of the active fraction (the sum of the unbound exposure of dapoxetine and desmethyldapoxetine) were decreased by 30% and 5%, repectively. In patients with moderate hepatic impairment, unbound Cmax of dapoxetine is essentially unchanged (decrease of 3%) and unbound AUC is increased by 66%. The unbound Cmax and AUC of the active fraction were essentially unchanged and doubled, respectively. In patients with severe hepatic impairment, the unbound Cmax of dapoxetine was decreased by 42% but the unbound AUC was increased by approximately 223%. The Cmax and AUC of the active fraction had similar changes (see sections 4.2 and 4.3).
CYP2D6 PolymorphismIn a single dose clinical pharmacology study using 60 mg dapoxetine, plasma concentrations in poor metabolizers of CYP2D6 were higher than in extensive metabolizers of CYP2D6 (approximately 31% higher for Cmax and 36% higher for AUCinf of dapoxetine and 98% higher for Cmax and 161% higher for AUCinf of desmethyldapoxetine). The active fraction of Priligy may be increased by approximately 46% at Cmax and by approximately 90% at AUC. This increase may result in a higher incidence and severity of dose dependent adverse events (see section 4.2). The safety of Priligy in poor metabolizers of CYP2D6 is of particular concern with concomitant administration of other medicinal products that may inhibit the metabolism of dapoxetine such as moderate and potent CYP3A4 inhibitors (see sections 4.2 and 4.3).
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