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Side Effects of Sildenafil (Viagra, Revatio)

FIND A PHARMACIST WHO OFFERS GENETIC TESTING FOR PDE5 Inhibitors

Description: Sildenafil, commonly known by its trade names Viagra and Revatio, is a PDE-5 inhibitor used in the treatment of a number of conditions including erectile dysfunction and, less commonly, hypertension. Viagra works by acting upon the the smooth muscle cells lining the blood vessels supplying the corpus cavernosum of the penis, thus causing an erection to occur.

 

Serious Side Effects of Viagra

 

Rare but potentially serious side effects of erectile dysfunction medications such as Viagra include:

  • Loss of vision
  • Loss of hearing
  • Palpitations (irregular heartbeat or fast beating heart)
  • Tachycardia (increased heart rate)
  • Hypertension (high blood pressure)
  • Hypotension (low blood pressure)
  • Myocardial infarction (heart attack)
  • Unstable angina (chest pain)
  • Syncope (fainting)
  • Cerebrovascular accident (bleed in the brain)
  • Lacrimation disorders (disorders of the tear system)
  • Priapism (a painful long-lasting erection which requires emergency treatment)

(Viagra label as reported by the FDA, January 2010).

 

Common Side Effects of Viagra

 

Common adverse effects of Viagra include:

  • Flushing
  • Dyspepsia (indigestion – up to 17% of patients)
  • Headache (up to 28% of patients)
  • Dizziness
  • Gastroesophageal reflux (GERD also known as acid reflux)
  • Diarrhea
  • Nausea
  • Diplopia (double vision)
  • Conjunctivitis (eye infection)
  • Sinus congestion
  • Throat tightness
  • Nasal edema
  • Nasal dryness
  • Rash
  • Eye pain
  • Vomiting
  • Dry mouth
  • Oral hypoaesthesia (reduced sense of touch)
  • Somnolence (feeling tired)
  • Hemorrhoids
  • Abdominal distension (bloating)
  • Pain in extremities (hands and feet)
  • Back pain
  • Myalgia (muscle pain)
  • Migraine
  • Tremor
  • Paresthesia (abnormal sensation such as tingling e.g., pins and needles)
  • Burning sensation
  • Abnormal vision
  • Visual color distortion
  • Visual impairment
  • Photophobia (increased sensitivity to light)
  • Cyanopsia (entire vision has a tint of blue)
  • Eye irritation
  • Chromatopsia (abnormal color vision)

How Does Pharmacogenetic Testing Work?

 

Most patients suffer no adverse effects when taking sildenafil while others may suffer severe adverse reactions or not therapeutically respond to the drug at all. This inter-patient, inter-variability, has a number of potential scientific reasons for the variation. One is the variable rates of metabolism in different patients. Sildenafil is metabolized by the cytochrome P450 superfamily of enzymes, predominantly isoenzyme CYP3A4 (but also to a less extent CYP2C9). Polymorphisms in these enzymes have been suggested to increase the probability of developing side effects when taking Sildenafil. There are also a number of genes associated with the NO and cGMP pathways that may result in increased or decreased probabilities of developing side effects (Pharmacogenomics “Pharmacogenetics of erectile dysfunction: navigating into uncharted waters,” Aug 2014).

Understand Your Risks with the Rxight® Genetic Test

 

By identifying which polymorphisms a patient has clinicians can alter doses of drugs such as Viagra/sildenafil. This may reduce the chances of developing side effects. Rxight® genetic testing identifies alleles on more than 18 genes to establish how a patient is likely to react to hundreds of clinically relevant medications, including sildenafil .

 

Email us or call 1 (888) 888-1932 to get started with Rxight® today.

 

 

Contributors to this Article:
Michael Sapko, MD, PhD; Deborah Kallick, PhD, Medicinal Chemistry

 

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