Difficulty in enjoying a satisfying sexual relationship that develops as a result of Parkinson’s disease or the medications taken to treat symptoms. The physical symptoms of Parkinson’s such as tremors and bradykinesia make movement and coordination difficult during sexual activity just as during walking. Many of the anti-parkinson’s medications affect smooth muscle function, which in turn affects sexual response in both men and women. Levodopa can induce dyskinesias that make the coordinated movements of sexual activity difficult. As well, emotional factors related to sexuality can result in sexual dysfunction.
Disruptions of nerve signals to smooth muscle tissue affect the ability of the penis to become erect, causing erectile dysfunction and delayed ejaculation in men. As well, factors of aging contribute to erectile difficulties. High blood pressure and diabetes, two medical conditions that become more common as people become older, can damage the tiny blood vessels, slowing the response of nerves in the penis and the flow of blood that creates an erection. Medications, such as some anti-parkinson’s medications and antidepressant medications, can further contribute to erectile dysfunction by slowing the physiological processes that result in a man’s sexual arousal. These same kinds of problems—impaired circulation and nerve function, and medication side effects—can cause difficulty with sexual response in women as well, interfering with the physiological processes of arousal and orgasm.
Certain dopamine receptors in the brain, most notably D1 receptors, play a role in perception of pleasure and in sexual desire. As dopamine levels in the brain decline, there is less dopamine present to bind with dopamine receptors. Although the most significant effect occurs on the D2 and D3 receptors that facilitate neuron communication related to movement, all dopamine receptors feel the effect. Ergot-derived dopamine agonist medications, such as bromocriptine (Parlodel) and pergolide (Permax), taken to provide dopamine-like stimulation in the brain sometimes produce a mild to moderate increase in libido in both men and women by increasing the activation of D1 receptors as well as suppressing the pituitary gland’s production of prolactin, a hormone associated with lactation in women and sex drive in both men and women. Lowering the body’s pro-lactin level increases sex drive.
Sexual dysfunction affects perhaps 60 percent or more of people who have Parkinson’s, men and women alike. Many are reluctant to discuss this problem with their doctors, either because they feel embarrassed or because they consider it unimportant as a medical disorder. improving sexual response and function could be as simple as changing the anti-Parkinson medication regimen, however, or adjusting dosages of other medications that are known to contribute to sexual dysfunction such as antidepressants and antihypertensive drugs taken for high blood pressure. As well, the medication sildenafil, better known as Viagra, can significantly improve a man’s ability to have and maintain erections.
