Explanation – The frequency of drugs are given based on its toxicity or the side effects in the body. All drugs have certain half-life in which there action is maximum and after that the drug is removed through the urine primarily.
Different people react differently to a drug and hence the doctors prescribe the anti-tablets for the side effects occurring. The drug for cold is prescribed after four hours because its effect gets reduced and has to be removed from the body.
I know one is to get tested. Another could be to use protection that could prevent that kind of stuff. Then if you're already infected, you should tell your partner. And if you do sleep with your partner while infected, tell them to get tested.