Therebound effect, also known as therebound phenomenon, refers to the re-emergence ofsymptoms that were previously absent or controlled while on medication, which occur when the medication is discontinued or the dosage is reduced. In cases of re-emergence, the symptoms are often more severe than they were before treatment.
The rebound effect, orpharmaceutical rebound phenomenon, is the emergence or re-emergence ofsymptoms that were either absent or controlled while taking a medication, but appear when that same medication is discontinued or reduced in dosage. In the case of re-emergence, the severity of the symptoms is often worse than pretreatment levels.[citation needed]
Rebound insomnia isinsomnia that occurs following discontinuation ofsedative substances taken to relieve primary insomnia. Regular use of these substances can cause a person to becomedependent on their effects in order to fall asleep. Therefore, when a person has stopped taking the medication and is 'rebounding' from its effects, they may experience insomnia as a symptom ofwithdrawal. Occasionally, this insomnia may be worse than the insomnia the drug was intended to treat.[1] Common medicines known to cause this problem areeszopiclone,zolpidem, andanxiolytics such asbenzodiazepines which are prescribed to people having difficulties falling or staying asleep.
Rebound depression may appear to arise in patients previously free of such an illness.[2]
Daytime rebound effects of anxiety, metallic taste, perceptual disturbances which are typicalbenzodiazepine withdrawal symptoms can occur the next day after a short-actingbenzodiazepine hypnotic wears off. Rebound phenomena do not necessarily only occur on discontinuation of a prescribed dosage. 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 istriazolam, due to its high potency and ultra short half-life, but these effects can occur with other short-actinghypnotic drugs.[3][4][5]Quazepam, due to its selectivity for type1 benzodiazepine receptors and long half-life, does not cause daytime anxiety rebound effects during treatment, showing that half-life is very important for determining whether a nighttimehypnotic will cause next-day rebound withdrawal effects or not.[6] Daytime rebound effects are not necessarily mild but can sometimes produce quite marked psychiatric and psychological disturbances.[7]
Rebound effects fromstimulants such asmethylphenidate ordextroamphetamine includestimulant psychosis,depression and a return of ADHD symptoms but in a temporarily exaggerated form.[8][9][10] Up to a third of ADHD children experience a rebound effect when methylphenidate is withdrawn.[11]
Manyantidepressants, includingSSRIs, can cause rebounddepression,panic attacks,anxiety, andinsomnia when discontinued.[12]
Sudden and severe emergence[13] or re-emergence[14] of psychosis may appear whenantipsychotics areswitched ordiscontinued too rapidly.
Rebound hypertension, above pre-treatment level, was observed afterclonidine[15] andguanfacine[16] discontinuation.
Continuous usage oftopical decongestants (nasal sprays) can lead to constantnasal congestion, known asrhinitis medicamentosa.
Denosumab inhibits osteoclast recycling, which results in the accumulation of pre-osteoclasts and osteomorphs. When denosumab therapy is discontinued, the induced cells quite quickly and abundantly differentiate into osteoclasts causingbone resorption (rebound effect) and increasing the risk of fractures. For improving mineral bone density and preventing fractures after denosumab discontinuation,bisphosphonate administration is recommended.[17]
Another example ofpharmaceutical rebound is arebound headache from painkillers when the dose is lowered, the medication wears off, or the drug is abruptly discontinued.[18]
In 2022, reports of viral RNA and symptom rebound in people withCOVID-19 treated withPaxlovid were published. In May, CDC even issued a health alert informing physicians about "Paxlovid rebounds", which received attention when US presidentJoe Biden experienced a rebound. The cause of the rebound is unclear however, since around a third of people with COVID-19 experience a symptom rebound regardless of treatment.[19]
Abrupt withdrawal of highly potentcorticosteroids, such asclobetasol forpsoriasis, can cause a much more severe case of the psoriasis to develop. Therefore, withdrawal should be gradual, until very little actual medication is being applied.[citation needed]