Drug holiday

A drug holiday (sometimes also called a drug vacation, medication vacation or structured treatment interruption) is when a medicated patient stops taking a drug for a period of time, from a few days to several months.

Planned drug holidays are used in several fields of medicine. They are perhaps best known in HIV therapy, after a study showed that stopping medication may stimulate the immune system to attack the virus.

As a treatment for HIV
HIV selectively targets activated helper T-cells. Over time, this means that HIV will tend to selectively destroy those helper T-cells most capable of fighting the HIV infection off, effectively desensitizing the immune system to the infection. The purpose of a structured treatement interruption in to create a short interval in which the virus becomes common enough to stimulate reproduction of T-cells capable of fighting the virus.

A 2006 HIV literature review noted that "two studies suggested that so-called drug holidays were of no benefit and might actually harm patients, while a third study suggested that the idea might still have value and should be revisited."

Other uses
Another reason for drug holidays is to permit a drug to regain effectiveness after a period of continuous use, and to reduce the tolerance effect that may require increased dosages.

In addition to drug holidays that are intended for therapeutic effect, they are sometimes used to reduce drug side effects so that patients may enjoy a more normal life for a period of time such as a weekend or holiday, or engage in a particular activity. For example, it is common for patients using SSRI anti-depressant therapies to take a drug holiday to reduce or avoid side effects associated with sexual dysfunction.