Common Oral Medications For Erectile Dysfunction

Erectile Dysfunction (ED) is one of the most frequently reported sexual health issues faced by men over 40 years of age. In most cases, the symptomatology becomes troublesome and men turn to medications in order to restore the normal quality of sex life.

Over the course of past few years, several drugs have been tested by medical researchers to ensure adequate efficacy (along with safety) in human subjects suffering from ED. Among the FDA-Cleared oral pharmacological options (that are rendered safe and effective for the management of ED); Tadalafil (Cialis), Vardenafil (Levitra) and Sildenafil (Viagra) are considered most superior and efficacious.

These three pharmacological agents belongs to the same class and have favorable results in the long term management of ED. There are few differences in the mode of action and activity of these agents, which should be considered while making your choice.

Following is a brief description of these common ED drugs.

Mechanism Of Action

Cialis, Levitra and Viagra belong to the class Phosphodiesterase-5 (PDE-5) Inhibitors. By blocking the action of the enzyme (Phosphodiesterase), these drugs increase the concentration of Nitric Oxide in the blood vessels. Nitric Oxide (or NO), is a naturally occurring chemical that acts as a vasodilator (causing widening of blood vessel) that supplies the genital region. NO also causes the penile muscles to relax; thereby further enhancing the blood flow to the organ of copulation (i.e. penis), thereby helping in its prolonged erection for better sexual activity.

Mode Of Administration And Pharmacokinetics

All 3 drugs are available in the oral formulation. Another form of Vardenafil is available as an over-the-counter formulation which easily dissolves when placed on the tongue. Cialis stays in the bloodstream for a minimum of 17-18 hours, whereas the other two drugs remain in the system for a period of 4-6 hours. This information needs to be kept in mind while taking other medications or if one is experiencing potential side effects of any drug. Also, if you are suffering from live or kidney dysfunction, this information helps in making careful decisions regarding ED drugs.

Dosing Schedule

Each drug is available in different strengths and has various regimens. One should use it exactly as prescribed by the physician and start from the lowest dose with gradual increments if needed.

Cialis:

• It is available in the form of a pill.
• It can be used about half an hour to an hour before sexual intercourse.
• It has no association with food intake.
• A more convenient once-daily (OD) dose is also available.

Levitra:

• It is prescribed as once-daily formulation.
• Once consumed, the action lasts for about 8 hours.
• It should be taken before meals or on an empty stomach.
• It is effective if one takes it 30-60 minutes before sex.

Viagra:

• It should be taken on an empty stomach.
• Its action lasts for 4-5 hours usually.
• Foods rich in fats should be avoided when using Viagra as fatty foods may delay its onset of action
• It works best if taken 30-60 minutes before engaging in sex.

Common Cautions And Adverse Effects with Common ED Drugs

Cialis:

• Body aches (including backache, myalgia and headache)

• Stomach related issues like nausea, or bowel upset
• Nasal congestion

Levitra and Viagra:

• Visual problems
• Excessive flushing of skin
• Stuffiness of nose and increased nasal secretions
• Gastric upset
• Headache

Dizziness is also a possible side effect of these drugs. Priapism is an uncommon drawback in which the penile erection is prolonged and painful (lasting up to a few hours longer than usual). An erection that lasts longer than 4 hours is considered as a state of medical emergency and care should be sought urgently to avoid the risk of permanent organ damage.

Any side effect should be reported to the doctor so that adequate measures are taken timely, or if required, change of drug should be advised.

Possible Drug-Drug Interactions

1. Nitrates:

All three medicines are absolutely contraindicated with nitrates as they may potentiate the action of PDE-5 inhibitors. Nitrates cause vasodilation and any combination can lead to a dangerous drop in the blood pressure.

Alpha Blockers:

These drugs are used for the management of hypertension and works by relaxing the blood vessels. PDE-5 inhibitor drugs interacts with alpha blockers to cause serious fall in the blood pressure.

Other Antihypertensive Drugs

According to the National Institute of Health, Viagra can abruptly lower the BP when used in combination with amlodipine. Cialis augments the effect of antihypertensive agents like amlodipine, enalapril, metoprolol etc. The similar action is followed by Levitra.

Alcohol:

It has been shown that Cialis strengthens the hypotensive effects of alcohol if taken along with it. It leads to postural hypotension resulting in dizziness and headache upon standing from sitting position.

Ritonavir:

This drug is used by HIV infected patients and has been known to interact with Viagra to increase the amount of blood to the blood vessels.

Appropriate use of any of these drugs can help overcome the erectile dysfunction. Discuss with your doctor about which medicine to choose keeping in view the mode of ingestion, side effects and interactions. Dosage adjustment is often required to achieve desirable effects.

References

1. Chen, L., Staubli, S. E., Schneider, M. P., Kessels, A. G., Ivic, S., Bachmann, L. M., & Kessler, T. M. (2015). Phosphodiesterase 5 inhibitors for the treatment of erectile dysfunction: a trade-off network meta-analysis. European urology, 68(4), 674-680.

2. Gresser, U., & Gleiter, C. H. (2002). Erectile dysfunction: comparison of efficacy and side effects of the PDE-5 inhibitors sildenafil, vardenafil and tadalafil-review of the literature. European journal of medical research, 7(10), 435-446.

3. Gur, S., J Kadowitz, P., Gokce, A., C Sikka, S., Lokman, U., & JG Hellstrom, W. (2013). Update on drug interactions with phosphodiesterase-5 inhibitors prescribed as first-line therapy for patients with erectile dysfunction or pulmonary hypertension. Current drug metabolism, 14(2), 265-269.