It’s no secret that allergy and cold medicines dry out your nose, but it also can affect your vagina. Many antihistamines can cause women, even women that aren’t yet in the menopausal stage, to suffer from vaginal dryness. When you take antihistamines, your doctor usually pairs them with decongestants. Both of these will dry you out down there because they work to reduce the amount of mucus your body will produce. If you think you will be heading to the bedroom or late-night activities during your cold or allergy season, be sure that you use lubrication. Not only can it be a cause of some painful sex, it can also create more serious problems.