Rebound effect

Rebound effect is the tendency of a medication to, when discontinued to cause a return of the symptoms being treated more severe than before. Medications with a known rebound effect can be withdrawn gradually or in conjunction with another medication which does not exhibit a rebound effect. The symptom will be more pronounced after the medication is withdrawn than before it was used.

Examples
Rebound anxiety

Several anxiolytics and hypnotics have a rebound effect: For example, benzodiazepine withdrawal can cause severe anxiety and insomnia worse than the original insomnia or anxiety disorder. Approximately 70% of patients who discontinue a benzodiazepine experience a rebound effect. Rebound withdrawal can be a factor in chronic use of medications and drug dependence with patients taking the medications only to ward off withdrawal or rebound withdrawal effects. Many antidepressants, such as SSRIs, can cause rebound depression or panic attacks and anxiety when discontinued.

Rebound insomnia

Rebound insomnia is insomnia that occurs following discontinuation of sedative substances taken to relieve primary insomnia. Regular use of these substances can cause a person to become dependent on its effects in order to fall asleep through the process of classical conditioning. Therefore, when a person has stopped taking the medication and is 'rebounding' from its effects, he or she may experience insomnia as a symptom of withdrawal. Occasionally, this insomnia may actually be worse than the insomnia the drug was intended to treat.

Common medicines known to cause this problem are Lunesta and Ambien, which are prescribed to people having difficulties falling or staying asleep. This phenomenon can also occur with regular use of anxiolytic drugs, such as benzodiazepines.

Daytime rebound

Rebound phenomena does not necessarily only occur on discontinuation of a prescribed dosage. For example day time rebound effects of anxiety, metallic taste, perceptual disturbances which are typical benzodiazepine withdrawal symptoms can occur the next day after a short acting benzodiazepine hypnotic wears off. Another example is early morning rebound insomnia which may occur when a rapidly eliminated hypnotic wears off which leads to rebounding awakeness forcing the person to become wide awake before he or she has had a full night's sleep. One drug which seems to be commonly associated with these problems is triazolam due to its high potency and ultra short half life but these effects can occur with other short acting hypnotic drugs. Quazepam due to its selectivity for type1 benzodiazepine receptors and long half life does not cause day time anxiety rebound effects during treatment, showing that half life is very important for determining whether a night time hypnotic will cause next day rebound withdrawal effects or not. Day time rebound effects are not necessarily mild but can sometimes produce quite marked psychiatric and psychological disturbances.

Other rebound effects

An example is the use of highly potent corticosteroids, such as Clobetasol for psoriasis. Abrupt withdrawal can cause a much more severe case of the psoriasis to develop. Therefore, withdrawal should be gradual, diluting the medication with lotion perhaps, until very little actual medication is being applied.

Another example of pharmaceutical rebound is a rebound headache from painkillers when dose is lowered, medication wears off or the drug is abruptly discontinued.

Continuous usage of topical decongestants (nasal sprays) can lead to constant nasal congestion, known as Rhinitis medicamentosa.