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VIAGRA (sildenafil citrate) Adverse Reactions

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Adverse Reactions

Adverse Drug Reaction Overview

Pre-Marketing Experience:

VIAGRA (sildenafil citrate) was administered to over 3700 patients (aged 19-87 years) during clinical trials worldwide. Over 550 patients were treated for longer than one year.

In placebo-controlled clinical studies, the discontinuation rate due to adverse events for VIAGRA (2.5%) was not significantly different from placebo (2.3%). The adverse events were generally transient and mild to moderate in nature.

Clinical Trial Adverse Drug Reactions

Because clinical trials are conducted under very specific conditions the adverse reaction rates observed in the clinical trials may not reflect the rates observed in practice and should not be compared to the rates in the clinical trials of another drug. Adverse drug reaction information from clinical trials is useful for identifying drug-related adverse events and for approximating rates.

In trials of all designs, adverse events reported by patients receiving VIAGRA were generally similar. In fixed-dose studies, the incidence of some adverse events increased with dose. The nature of the adverse events in flexible-dose studies, which more closely reflect the recommended dosage regimen, was similar to that for fixed-dose studies.

When VIAGRA was taken as recommended (on an as-needed basis) in flexible-dose, placebo-controlled clinical trials, the following adverse events were reported:

Table 1. Adverse Events Reported by ≥2% of Patients Treated with VIAGRA or Placebo in PRN Flexible-Dose Phase II/III Studies
Adverse EventPercentage of Patients Reporting Event
VIAGRA (n=734)PLACEBO (n=725)
Headache15.8%3.9%
Flushing10.5%0.7%
Dyspepsia6.5%1.7%
Nasal Congestion4.2%1.5%
Respiratory Tract Infection4.2%5.4%
Flu Syndrome3.3%2.9%
Urinary Tract Infection3.1%1.5%
Abnormal Vision*2.7%0.4%
Diarrhea2.6%1.0%
Dizziness2.2%1.2%
Rash2.2%1.4%
Back Pain2.2%1.7%
Arthralgia2.0%1.5%

* Abnormal Vision: Mild and transient changes, predominantly impairment of colour discrimination (blue/green), but also increased perception to light or blurred vision.

At doses above the recommended dose range, adverse events were similar to those detailed above but generally were reported more frequently.

Less Common Clinical Trial Adverse Drug Reactions (<2%)

The following events occurred in <2% of patients in in phase II/III controlled clinical trials where a causal relationship is uncertain:

Autonomic:sweating, dry mouth;
Cardiovascular:abnormal electrocardiogram, angina pectoris, arrhythmia, AV block, cardiac arrest, cardiomyopathy, heart failure, hypertension, hypotension, palpitation, postural hypotension, myocardial ischemia, syncope, tachycardia, varicose vein, vascular anomaly;
Central & Peripheral
Nervous System:
tremor, abnormal dreams, anxiety, agitation, ataxia, depression, insomnia, nervousness, somnolence, paresthesia, vertigo, speech disorder, reflexes decreased, hyperesthesia, neuropathy, migraine, myasthenia, oculogyric crisis, neuralgia, hypertonia;
Gastrointestinal:vomiting, gastritis, gastrointestinal disorder, flatulence, increased appetite, gastroenteritis, stomatitis, eructation, dysphagia, colitis, glossitis, constipation, rectal hemorrhage, mouth ulceration, esophagitis, rectal disorder, gingivitis, tooth disorder;
Hematopoietic:anemia and leukopenia;
Liver/Biliary:liver function tests abnormal, ALT increased;
Metabolic/Nutritional:edema, thirst, gout, hyperuricemia, hypoglycemic reaction, unstable diabetes, hyperglycemia, hyperlipidemia, hypernatremia;
Musculoskeletal:myalgia, bone disorder, arthrosis, arthritis, tendon rupture, tenosynovitis, bone pain, joint disorder, synovitis;
Respiratory:asthma, dyspnea, laryngitis, pharyngitis, sinusitis, bronchitis, respiratory disorder, carcinoma of lung, sputum increased, cough increased;
Skin/Appendages:skin carcinoma, skin disorder, skin hypertrophy, skin ulcer, contact dermatitis, exfoliative dermatitis, pruritus, urticaria, photosensitivity reaction, nail disorder, acne, herpes simplex, furunculosis;
Special Senses:Sudden decrease or loss of hearing, mydriasis, conjunctivitis, photophobia, eye pain, tinnitus, ear pain, lacrimation disorder, eye disorder, eye hemorrhage, ear disorder, cataract, dry eyes;
Urogenital:penile erection, other sexual dysfunction, cystitis, nocturia, balanitis, urinary frequency, breast enlargement, prostatic disorder, testis disorder, urinary incontinence, urinary tract disorder, urine abnormality, abnormal ejaculation, genital edema and anorgasmia;
Vascular Disorders:cerebrovascular disorder, cerebral thrombosis;
General:face edema, peripheral edema, chills, allergic reaction, asthenia, pain, infection, shock, hernia, accidental fall, abdominal pain, chest pain, accidental injury, intentional overdose.

Myocardial Infarction and Cardiovascular Mortality

In an analysis of double blind placebo controlled clinical trials encompassing over 700 person-years of observation on placebo and over 1300 person-years on sildenafil, there were no differences in the incidence rate of myocardial infarction (MI) or in the rate of cardiovascular mortality for patients receiving sildenafil compared to those receiving placebo. The rates of MI were 1.1 per 100 person-years for men receiving sildenafil and for those receiving placebo. The rates of cardiovascular mortality were 0.3 per 100 person-years for men receiving sildenafil and those receiving placebo.

Clinical Trial Adverse Drug Reactions Reported in 74 Double-Blind Placebo-Controlled Phase II/III/IV Studies

When VIAGRA was taken as recommended in 74 randomized double-blind, placebo-controlled (DBPC) Phase II/III/IV studies, adverse reactions reported by ≥2% of patients treated with VIAGRA (n=9,570) and more frequently than placebo (n=7,237) were headache, flushing, dyspepsia, nasal congestion and dizziness. The nature and frequency of adverse reactions reported by ≥2% of patients in this pooled dataset of 74 DBPC studies was consistent with the adverse reactions reported in the 6 flexible-dose studies detailed above in Table 1.

The following adverse reactions occurred in <2% of patients in the 74 DBPC clinical trials.

Cardiac disorders:

palpitations, tachycardia;

Eye disorders:

vision blurred, chromatopsia, cyanopsia, photophobia, visual disturbance, photopsia, ocular hyperaemia, eye pain, visual brightness, abnormal sensation in eye, asthenopia, conjunctival hyperaemia, dry eye, erythropsia, eye disorder, eye irritation, eye edema, eyelid edema, eye swelling, halo vision, xanthopsia;

Gastrointestinal disorders:

nausea, dry mouth, abdominal pain upper, vomiting, gastroesophageal reflux disease, oral hypoaesthesia;

General conditions and administration site conditions:

feeling hot, irritability;

Immune system disorders:

hypersensitivity;

Infections and infestations:

rhinitis;

Investigations:

heart rate increased;

Musculoskeletal and connective tissue disorders:

pain in extremity, myalgia;

Nervous system disorders:

syncope, somnolence;

Reproductive system and breast disorders:

erection increased;

Respiratory, thoracic and mediastinal disorders:

epistaxis, sinus congestion, nasal oedema, nasal dryness, throat tightness;

Skin and subcutaneous tissue disorders:

rash;

Vascular disorders:

hot flush, hypotension.

Post-Market Adverse Drug Reactions

Reports of adverse events temporally associated with VIAGRA during post-marketing surveillance that are not listed above and for which the causal relationship is unknown, include the following:

Cardiovascular:
Epistaxis; serious cardiovascular events - including myocardial infarction, sudden cardiac death, ventricular arrhythmia, cerebrovascular hemorrhage, and transient ischemic attack - have been reported. Most of these patients had pre-existing cardiovascular risk factors. Many of these events were reported to occur during or shortly after sexual activity, and a few were reported to occur shortly after the use of VIAGRA without sexual activity. Others were reported to have occurred hours to days after the use of VIAGRA with sexual activity. It is not possible to determine whether these events are related directly to VIAGRA, to sexual activity, to the patient's underlying cardiovascular disease, to combination of these factors, or to other factors (see WARNINGS AND PRECAUTIONS).

Central & Peripheral
Nervous System:
seizure, seizure recurrence, transient global amnesia;
Gastrointestinal:vomiting;
Urogenital:prolonged erection, priapism (see WARNINGS AND PRECAUTIONS) and hematuria;
Skin / Appendages:Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN)
Special Senses:diplopia, temporary vision loss/decreased vision, blurred vision, Non-Arteritic Anterior Ischemic Optic Neuropathy (NAION) , retinal vein occlusion, visual field defect, eye pain, ocular redness or bloodshot appearance, ocular burning, ocular swelling/pressure, increased intraocular pressure, retinal vascular disease of bleeding, vitreous detachment/traction and paramacular edema.

Cases of sudden decrease or loss of hearing have been reported post-marketing in temporal association with the use of PDE5 inhibitors, including VIAGRA. In some of the cases, medical conditions and other factors were reported that may have also played a role in the otologic adverse events. In many cases, medical follow-up information was limited. It is not possible to determine whether these events are related directly to the use of VIAGRA, to the patient’s underlying risk factors for hearing loss, a combination of these factors, or to other factors (see WARNINGS AND PRECAUTIONS, ADVERSE REACTIONS and PART III CONSUMER INFORMATION).

Rare cases of central serous chorioretinopathy have been reported during the post-marketing period in temporal association with the use of sildenafil citrate. It is not known if medical and other facts were reported that may have also played a role in the development of the condition. It is not possible to determine whether the development of the condition was related directly to the use of sildenafil, to the patient’s possible underlying risk factors, a combination of these factors, or to other factors. These cases of central serous chorioretinopathy in patients receiving sildenafil did not provide evidence of serious or permanent alteration in visual function. (SEE WARNINGS AND PRECAUTIONS).