Does Viagra Show Up on a Drug Test?

This question has created concerns for anyone who is planning to enter in the fields of sports or military where tests are carried out to check for substances that may boost hormones and metabolism, typically human growth factors, anabolic steroids, erythropoietin, diuretics, alcohol, illegal recreational drugs (such as Viagra) or drugs that are listed on the world anti-doping code prohibited list.

Routine drug testing and pre-employment screening don’t specifically test for Viagra. These testing doesn’t show false positives, too, since even its metabolites are not detected. Specific testing like GC/MS, HPLC/MS, may detect Viagra.

The use of Viagra is not illegal, but people are not comfortable sharing it probably because of embarrassment. They might not want to share this with their employer because of personal reasons.

Viagra does not directly enhance metabolism, so there is nothing to worry about.

Drug Testing

Drug testing uses chemical technology to screen for illegal or under prescription drugs or its metabolites in one’s body fluid such as blood, urine, saliva, hair, or sweat.

Urine Testing is most commonly implemented. These tests are mainly done as part of pre-employment screenings, post accidental investigations (forensic purposes), and military or sports organizations can use it to detect high-performance drug by doping.

Types of Drug Testing

Blood testing

It is the most accurate, invasive, and expensive drug testing method used widely in clinical settings. It can even detect the concentration of drugs present at a particular time. Blood samples are taken to test Viagra metabolites. The test can only be positive if the sample is taken half an hour of ingestion (1).

Urine Testing

Urine testing is the most common since Urine is the main excretory route of all the drugs that undergo metabolism in our body after being ingested. This testing works for short term detection of about 48-72 hours (2). Drugs like cocaine, heroin, and amphetamines can easily be detected in this time frame. This test can also detect viagra.

Sweat testing is a less invasive method developed; lately, it requires a sweat patch attached to the skin to be worn for a few days. Sweat is absorbed by a cellulose pad, and it is assayed using gas chromatography-mass chromatography (GC/MS)(3).

Methods of Drug testing

Drug testing requires two phases; screening and confirmation. Initially, Immunoassay (IA) test is done. Results are usually available in 10 minutes. The testing stops after Immunoassay if it’s harmful but since there is a chance of cross-reactivity due to similar chemical structure.

A further confirmatory test like Gas chromatography/mass spectrometry (GC/Ms) or High-pressure liquid chromatography/mass spectrometry (HPLC/MS) is employed. A combination of both tests can give accurate results, thus lowering the chances for any false positive or false negative.

Viagra: Metabolism and Elimination

Viagra or Sildenafil is a potent drug to treat Erectile dysfunction. It is orally effective with an approximate 30 minutes duration of action (4). Viagra has a half-life between 2 to 4 hours.

It works by inhibiting the phosphodiesterase-5 enzyme. By inhibiting this enzyme, it causes smooth muscle to relax, which, in turn, promotes the widening of arteries. This provides a surge of blood to the penile arteries, producing an erection.

Metabolism

Viagra uses cytochrome p450 enzymes for its metabolism and takes place inside the liver.

The active metabolite of Viagra is N-demethylated sildenafil that is responsible for the drug’s action (5). Its absorption is affected if taken with a fatty meal. Its maximum concentration in plasma is achieved after one hour of its introduction.

The drug is excreted as metabolites predominantly in the feces and, to a lesser extent in the urine. Therefore, blood tests are preferably done to detect if metabolites are present or not.

Elimination

The half-life of Viagra (Sildenafil) is of four hours approximately. This indicates that the concentration of the drug will be reduced by half every four hours (6).

Viagra takes five to six hours to leave the body completely, but the rate of elimination varies with the dosage. A higher dosage will take longer to exit from the body.

Drug Tests for Viagra

Viagra does show up on a drug test. However, routine employment drug screenings do not test for Viagra; it is usually tested if Viagra toxicity is suspected.

Viagra is detectable 30 minutes after ingesting the drug. Blood, urine, or saliva samples are taken to detect the presence of Viagra metabolites. Gas chromatography/mass spectrometry (GC/Ms) or High-pressure liquid chromatography/mass spectrometry (HPLC/MS) is commonly employed methods.

References

1. Nichols, D. J., Muirhead, G. J., & Harness, J. A. (2002). Pharmacokinetics of sildenafil after single oral doses in healthy male subjects: absolute bioavailability, food effects, and dose proportionality. British journal of clinical pharmacology, 53 Suppl 1(Suppl 1), 5S–12S. doi:10.1046/j.0306-5251.2001.00027.x
2. Eardley I, Ellis P, Boolell M, Wulff M. Onset and duration of action of sildenafil for the treatment of erectile dysfunction. British journal of clinical pharmacology. 2002 Feb;53:61S-5S.
3. Man CN, Nor NM, Lajis R, Harn GL. Identification of sildenafil, tadalafil and vardenafil by gas chromatography–mass spectrometry on short capillary column. Journal of Chromatography A. 2009 Nov 20;1216(47):8426-30.
4. Brock G. Sildenafil citrate (Viagra®). Drugs Today. 2000 Feb 1;36(2-3):125-34.
5. Hyland R, Roe EG, Jones BC, Smith DA. Identification of the cytochrome P450 enzymes involved in the N‐demethylation of sildenafil. British journal of clinical pharmacology. 2001 Mar;51(3):239-48.
6. Boolell M, Allen MJ, Ballard SA, Gepi-Attee S, Muirhead GJ, Naylor AM, Osterloh IH, Gingell C. Sildenafil: an orally active type 5 cyclic GMP-specific phosphodiesterase inhibitor for the treatment of penile erectile dysfunction. International journal of impotence research. 1996 Jun;8(2):47-52.