Visual hallucination and tremor induced by sertraline and oxycodone in a bone marrow transplant patient

Hallucinations: diagnosis, neurobiology and clinical management

Hallucinations are important diagnostic symptoms in schizophrenia, but also occur in other medical and neuropsychiatric conditions. Not all patients with hallucinations are psychotic. There has been a surge of interest in the topic of hallucinations, as new research data have begun to reveal their neurobiology. Hallucinogenic molecules may also serve as new scaffolds for the development of new psychotropic drugs. We searched and reviewed recent literature, focusing on the refinement of clinical management, which was inspired by new data regarding the neurobiology of hallucination subtypes. We concluded that the successful management of hallucinations depends on accurate differential diagnosis to identify subtypes, which would then determine the most appropriate treatment.

The impact of drug interactions on adverse effects of oral oxycodone in male geriatric patients

WHAT IS KNOWN AND OBJECTIVE

With increased opioid use, drug-drug interactions (DDIs) and associated adverse events are growing among geriatric patients. However, the clinical significance of potential metabolic DDIs associated with opioid use has not been fully evaluated among geriatric patients. Particularly, cytochrome (CYP) P450 enzymes are important in drug metabolism of oxycodone and a black box warning for oxycodone reveals serious risks associated with drug-oxycodone interactions. This study focused on the use of oxycodone in geriatric patients to evaluate its adverse drug reactions (ADRs) and DDIs associated with CYP P450 enzymes.

METHODS

A retrospective cohort study using patients treated at Korea Veterans Hospital was performed. Data from male patients aged 65 years and older who received oxycodone were analysed. Binomial variables describing patient-related characteristics, drug-related characteristics and CYP-mediating drugs were constructed. Associations between these variables and the frequency of ADRs were determined. The odds ratio (OR) and adjusted odds ratio (AOR) were calculated from univariable and multivariable analyses, respectively.

RESULTS AND DISCUSSION

Among 111 patients, 32.4% experienced at least one ADR. The most common ADR was gastrointestinal-related (n = 21), followed by dizziness and drowsiness (n = 8). Use of either CYP2D6 inhibitors or CYP3A4 inhibitors increased the rate of ADRs by 20.4 and 25.4 times, respectively. In the case of patients taking both inhibitors, the adjusted OR was 48.6, and the attributable risk was 97.9%.

WHAT IS NEW AND CONCLUSION

This study suggests that inappropriate combinations of oxycodone with CYP2D6 inhibitors and/or CYP3A4 inhibitors may warrant treatment modification to avoid ADRs in geriatric patients. Clinicians should monitor any signs of ADRs that may reflect DDIs while a geriatric patient is taking oxycodone.

Opioid-induced Hallucinations: A Review of the Literature, Pathophysiology, Diagnosis, and Treatment

Despite their association with multiple adverse effects, opioid prescription continues to increase. Opioid-induced hallucination is an uncommon yet significant adverse effect of opioid treatment. The practitioner may encounter patient reluctance to volunteer the occurrence of this phenomenon because of fears of being judged mentally unsound. The majority of the literature concerning opioid-induced hallucinations arises from treatment during end-of-life care and cancer pain. Because the rate of opioid prescriptions continues to increase in the population, the rate of opioid-associated hallucinations may also conceivably increase. With a forecasted increase in the patient-to-physician ratio, opioid therapy is predicted to be provided by practitioners of varying backgrounds and medical specialties. Hence, knowledge of the pharmacology and potential adverse effects of these agents is required. This review seeks to increase awareness of this potential complication through a discussion of the literature, potential mechanisms of action, diagnosis, and treatment strategies.

Interaction between tramadol and selective serotonin reuptake inhibitors: are doctors aware of potential risks in their prescription practice?

Objectives

The combination of a selective serotonin reuptake inhibitor (SSRI) or serotonin-norepinephrine reuptake inhibitor (SNRI) with tramadol can result in serotonin syndrome, characterised by neuromuscular and autonomic nervous system excitation and altered mental state. The incidence of serotonin syndrome with this combination of drugs is low, and the serotonin syndrome is generally mild or moderate in form, but can be life threatening and is more easily prevented than treated. We aimed to investigate whether prescribers in a general hospital were aware of this risk and if it influenced their prescriptions.

Methods

A questionnaire was sent to 194 physicians in a general teaching hospital with over 650 beds in The Netherlands. The questionnaire presented four cases, two of whom used an SSRI or SNRI among other medications, and asked the respondents to prescribe an opioid in each case. The respondents were not aware of the focus of our research. Actual prescription rates of tramadol in admitted patients who did or did not use an SSRI or SNRI were assessed using the hospital pharmacy database.

Results

Based on the questionnaire, respondents prescribed tramadol equally in patients with or without concomitant use of SSRIs/SNRIs. About one-third of respondents who prescribed tramadol indicated they were aware of the potential interaction with SSRIs/SNRIs. About one-fifth deliberately avoided tramadol because a potential interaction with SSRIs/SNRIs was identified. However, there was no difference in actual tramadol prescriptions, as recorded in the hospital pharmacy database: 23.8% of SSRI/SNRI users received tramadol versus 24.6% of non-SSRI/SNRI-users (calculated OR 0.96; 95% CI 0.78 to 1.17).

Conclusions

In total, 20-30% of prescribers in a general hospital were aware of the potential interaction between tramadol and SSRIs or SNRIs, yet this did not translate to a difference in tramadol prescriptions between SSRI/SNRI users and non-users, as documented in the hospital pharmacy database. A physician's decision to prescribe tramadol to SSRI/SNRI users may be guided by a comprehensive individual benefit-risk assessment; expected benefits of tramadol may outweigh the small risk of serotonin syndrome. In order to increase awareness of the potential risk of a serotonin syndrome, hospital pharmacies may play an important role in signalling the potential interaction and providing information on the benefits and risks of tramadol and alternative analgesics in the presence of SSRIs or SNRIs.

Serotonin Syndrome Induced by Fluvoxamine and Oxycodone

Objective:

To report a case of severe serotonergic symptoms following the addition of oxycodone to fluvoxamine.

Case Summary:

A 70-year-old woman developed severe serotonergic features, including confusion, nausea, fever, clonus, hyperreflexia, hypertonia, shivering, and tachycardia, following the addition of oxycodone 40 mg twice daily to fluvoxamine 200 mg/day, easily fulfilling diagnostic criteria for serotonin syndrome. Discontinuation of the offending drugs resulted in resolution of her symptoms over 48 hours, and no other cause of the syndrome was identified. Use of the Naranjo probability scale indicated a probable relationship between the serotonergic symptoms and the addition of oxycodone to fluvoxamine therapy.

Discussion:

Serotonin syndrome is a serious adverse reaction usually due to interactions with serotonergic drugs. There have been only 3 previous reports involving oxycodone. Most previous reports of serotonin syndrome involving analgesics have been associated with meperidine, dextromethorphan, and tramadol. Unlike these synthetic opioids, however, oxycodone does not inhibit the reuptake of serotonin. In addition, there are a number of other possible pharmacologic mechanisms for the interaction we observed.

Conclusions:

Monitoring for serotonergic adverse events should be done when oxycodone is given to patients receiving serotonin-reuptake inhibitors.

Clinically significant drug-drug interactions involving opioid analgesics used for pain treatment in patients with cancer: a systematic review

BACKGROUND

Opioids are the most frequently used drugs to treat pain in cancer patients. In some patients, however, opioids can cause adverse effects and drug-drug interactions. No advice concerning the combination of opioids and other drugs is given in the current European guidelines.

OBJECTIVE

To identify studies that report clinically significant drug-drug interactions involving opioids used for pain treatment in adult cancer patients.

DESIGN AND DATA SOURCES

Systematic review with searches in Embase, MEDLINE, and Cochrane Central Register of Controlled Trials from the start of the databases (Embase from 1980) through January 2014. In addition, reference lists of relevant full-text papers were hand-searched.

RESULTS

Of 901 retrieved papers, 112 were considered as potentially eligible. After full-text reading, 17 were included in the final analysis, together with 15 papers identified through hand-searching of reference lists. All of the 32 included publications were case reports or case series. Clinical manifestations of drug-drug interactions involving opioids were grouped as follows: 1) sedation and respiratory depression, 2) other central nervous system symptoms, 3) impairment of pain control and/or opioid withdrawal, and 4) other symptoms. The most common mechanisms eliciting drug-drug interactions were alteration of opioid metabolism by inhibiting the activity of cytochrome P450 3A4 and pharmacodynamic interactions due to the combined effect on opioid, dopaminergic, cholinergic, and serotonergic activity in the central nervous system.

CONCLUSION

Evidence for drug-drug interactions associated with opioids used for pain treatment in cancer patients is very limited. Still, the cases identified in this systematic review give some important suggestions for clinical practice. Physicians prescribing opioids should recognize the risk of drug-drug interactions and if possible avoid polypharmacy.

Serotonin syndrome probably triggered by a morphine-phenelzine interaction

Serotonin syndrome is a potentially life-threatening condition caused by excessive central and peripheral stimulation of serotonin brainstem receptors, usually triggered by inadvertent interactions between agents with serotonergic activity. Evidence supporting an association between nonserotonergic opiates, such as oxycodone or morphine, and serotonin syndrome is very limited and even contradictory. In this case report, we describe a patient who developed serotonergic-adverse effects likely precipitated by an interaction between morphine and phenelzine. A 57-year-old woman presented to the emergency department with complaints of increasing visual hallucinations, restlessness, photophobia, dizziness, neck stiffness, occipital headache, confusion, sweating, tachycardia, and nausea over the previous week. On admission, her blood pressure was 185/65 mm Hg, and clonus was noted in the lower extremities. The patient was hospitalized 10 days earlier for cellulitis of the left breast secondary to a left mastectomy 5 months earlier, and a short course of oral morphine was prescribed for pain control. Her routine medications consisted of aspirin, atorvastatin, bisoprolol, clopidogrel, gabapentin, omeprazole, phenelzine, and ramipril. Supportive measures were initiated on admission. Phenelzine and morphine were discontinued immediately, leading to a progressive resolution of symptoms over the next 48 hours. Phenelzine was restarted on discharge without further complications. Use of the Drug Interaction Probability Scale indicated a probable relationship (score of 6) between the patient's development of serotonin syndrome and the combination of morphine and phenelzine. The mechanism underlying this interaction, however, remains unclear and warrants further investigation. Clinicians should carefully weigh the risk and benefits of initiating morphine in patients taking monoamine oxidase inhibitors or any other serotonin-enhancing drugs.

Pharmacologic safety concerns in Parkinson's disease: facts and insights

Knowledge and insight of pharmacologic safety issues and drug interactions are important for medical management of Parkinson's disease (PD). This review will discuss several topics, including apomorphine safety and interactions, impulsivity and excessive daytime somnolence associated with dopamine agonists (DAs), tolcapone hepatotoxicity, and monoamine oxidase type-B (MAO-B) inhibitor drug interactions. Initiation of apomorphine requires antiemetic prophylaxis to minimize nausea and orthostatic hypotension. Centrally acting antidopaminergic antiemetics will worsen parkinsonism and block the therapeutic effects of apomorphine and should be avoided. Additionally, serotonin 5-HT(3) receptor antagonist antiemetics should be avoided on the basis of limited clinical data suggesting lack of efficacy for apomorphine-induced nausea. Dopamine-agonist-induced impulsivity and daytime somnolence are not uncommon. When severe, these effects can be disabling and unsafe. Tolcapone-induced hepatotoxicity has been significantly minimized with routine monitoring of liver enzymes, especially during the initial 6 months of therapy. Early detection of abnormal results will allow tolcapone discontinuation before progression to fulminant hepatotoxicity. In patients treated with selective MAO-B inhibitors, the risk of serotonin toxicity (ST) due to a concomitant serotonergic agent (e.g., antidepressants, dextromethorphan, serotonergic analgesics) or hypertensive crisis due to dietary tyramine or sympathomimetic amines appears to be minimal and is based on isolated case reports and overgeneralizations from nonselective MAO inhibitor pharmacology. Concerns about ST or hypertensive crisis should not preclude or restrict clinicians from using MAO-B inhibitors in patients with PD.

An unusual case of serotonin syndrome with oxycodone and citalopram

A 77-year-old female with recurrent non-small-cell lung cancer presented to a hospital outpatient clinic with tremor, weakness, inability to coordinate motor movements, and confusion. It was suspected that the symptoms were due to possible central nervous system metastases; however, a CT scan of her head was unremarkable. The lung clinic liaison pharmacist took a medication history from the patient, complimented by extra information from the patient's community pharmacy. The pharmacist suspected the rare side effect of serotonin syndrome was responsible for the patient's presenting symptoms caused by the combination of oxycodone and citalopram. The patient's symptoms resolved soon after oxycodone was changed to morphine.

A case of serial nightmares and oneiroid state under paroxetine for senile depression

We report on rare side effects of paroxetine. A 67-year-old female patient who had been suffering from prolonged depression for over a year but had not received appropriate treatment was administered 20-mg paroxetine daily. However, the patient required hospital admission after 16 days because of behavioural disturbances and delusions that she was being chased by evil persons from a religious group. The delusions were ultimately confirmed to be serial nightmares and an oneiroid state. The nightmares gradually disappeared following discontinuation of paroxetine. The Adverse Drug Reaction Probability Scale showed a score of 6 (probable). Reports on paroxetine-induced nightmares are rare, and there is a possibility that, in this case, parexetine caused the nightmares in association with depression and assumed underlying brain dysfunction due to ageing.

Drug-induced hyperkinetic movement disorders by nonneuroleptic agents

Hyperkinetic movement disorders are characterized by excess movement, and include chorea, akathesia, asterixis, dystonia, tremor, myoclonus, and tics. A wide variety of pharmacologic agents may induce or exacerbate these disorders. Neuroleptic-induced tardive dyskinesia and levodopa-induced hyperkinesia are the most common causes of medication-induced chorea. However, several nonneuroleptic agents, including antidepressants and antiepileptic medications, may also worsen hyperkinetic movement disorders. Over-the-counter medications, such as analgesics and antiheartburn medications, have also occasionally been implicated as causing hyperkinetic movement disorders. Most information regarding drug-induced hyperkinetic disorders comes from case reports and anecdotes, rather than controlled clinical trials. Further research with larger controlled trials needs to verify many of these findings.

Genetic polymorphisms and drug interactions modulating CYP2D6 and CYP3A activities have a major effect on oxycodone analgesic efficacy and safety

BACKGROUND AND PURPOSE

The major drug-metabolizing enzymes for the oxidation of oxycodone are CYP2D6 and CYP3A. A high interindividual variability in the activity of these enzymes because of genetic polymorphisms and/or drug-drug interactions is well established. The possible role of an active metabolite in the pharmacodynamics of oxycodone has been questioned and the importance of CYP3A-mediated effects on the pharmacokinetics and pharmacodynamics of oxycodone has been poorly explored.

EXPERIMENTAL APPROACH

We conducted a randomized crossover (five arms) double-blind placebo-controlled study in 10 healthy volunteers genotyped for CYP2D6. Oral oxycodone (0.2 mg x kg(-1)) was given alone or after inhibition of CYP2D6 (with quinidine) and/or of CYP3A (with ketoconazole). Experimental pain (cold pressor test, electrical stimulation, thermode), pupil size, psychomotor effects and toxicity were assessed.

KEY RESULTS

CYP2D6 activity was correlated with oxycodone experimental pain assessment. CYP2D6 ultra-rapid metabolizers experienced increased pharmacodynamic effects, whereas cold pressor test and pupil size were unchanged in CYP2D6 poor metabolizers, relative to extensive metabolizers. CYP2D6 blockade reduced subjective pain threshold (SPT) for oxycodone by 30% and the response was similar to placebo. CYP3A4 blockade had a major effect on all pharmacodynamic assessments and SPT increased by 15%. Oxymorphone C(max) was correlated with SPT assessment (rho(S)= 0.7) and the only independent positive predictor of SPT. Side-effects were observed after CYP3A4 blockade and/or in CYP2D6 ultra-rapid metabolizers.

CONCLUSIONS AND IMPLICATIONS

The modulation of CYP2D6 and CYP3A activities had clear effects on oxycodone pharmacodynamics and these effects were dependent on CYP2D6 genetic polymorphism.

Does co-administration of paroxetine change oxycodone analgesia: An interaction study in chronic pain patients

Oxycodone is a strong opioid and it is increasingly used in the management of acute and chronic pain. The pharmacodynamic effects of oxycodone are mainly mediated by the μ-opioid receptor. However, its affinity for the μ-opioid receptor is significantly lower compared with that of morphine and it has been suggested that active metabolites may play a role in oxycodone analgesia. Oxycodone is mainly metabolized by hepatic cytochrome (CYP) enzymes 2D6 and 3A4. Oxycodone is metabolized to oxymorphone, a potent μ-opioid receptor agonist by CYP2D6. However, CYP3A4 is quantitatively a more important metabolic pathway. Chronic pain patients often use multiple medications. Therefore it is important to understand how blocking or inducing these metabolic pathways may affect oxycodone induced analgesia. The aim of this study was to find out whether blocking CYP2D6 would decrease oxycodone induced analgesia in chronic pain patients.

The effects of the antidepressant paroxetine, a potent inhibitor of CYP2D6, on the analgesic effects and pharmacokinetics of oral oxycodone were studied in 20 chronic pain patients using a randomized, double-blind, placebo-controlled cross-over study design. Pain intensity and rescue analgesics were recorded daily, and the pharmacokinetics and pharmacodynamics of oxycodone were studied on the 7th day of concomitant paroxetine (20 mg/day) or placebo administration. The patients were genotyped for CYP2D6, 3A4, 3A5 and ABCB1.

Paroxetine had significant effects on the metabolism of oxycodone but it had no statistically significant effect on oxycodone analgesia or use of morphine for rescue analgesia. Paroxetine increased the dose-adjusted mean AUC0–12h of oxycodone by 19% (−23 to 113%; P = 0.003), and that of noroxycodone by 100% (5–280%; P < 0.0001) but decreased the AUC0–12 h of oxymorphone by 67% (−100 to −22%; P < 0.0001) and that of noroxymorphone by 68% (−100 to −16%; P < 0.0001).

Adverse effects were also recorded in a pain diary for both 7-day periods (placebo/paroxetine). The most common adverse effects were drowsiness and nausea/vomiting. One patient out of four reported dizziness and headache during paroxetine co-administration, whereas no patient reported these during placebo administration (P = 0.0471) indicating that these adverse effects were due to paroxetine.

No statistically significant associations of the CYP2D6 or CYP3A4/5 genotype of the patients and the pharmacokinetics of oxycodone or its metabolites, extent of paroxetine–oxycodone interaction, or analgesic effects were observed probably due to the limited number of patients studied.

The results of this study strongly suggest that CYP2D6 inhibition does not significantly change oxycodone analgesia in chronic pain patients and that the analgesic activity of oxycodone is mainly due to the parent compound and that metabolites, e.g. oxymorphone, play an insignificant role. The clinical implication of these results is that induction of the metabolism of oxycodone may lead to inadequate analgesia while increased drug effects can be expected after addition of potent CYP3A4/5 inhibitors particularly if combined with CYP2D6 inhibitors or when administered to poor metabolizers of CYP2D6.

Serotonin syndrome triggered by a single dose of suboxone

Suboxone (buprenorphine/naloxone) is an oral medication used for the treatment of opiate dependence. Because of its mixed properties at the opiate receptors, buprenorphine has a ceiling on its euphoric effects. We report the first case of serotonin syndrome caused by buprenorphine and review other medications implicated in serotonin syndrome. A 54-year-old man on tricyclic antidepressants took an unprescribed dose of buprenorphine/naloxone. He presented to the emergency department with signs and symptoms of severe serotonin syndrome including clonus, agitation, and altered mental status. His agitation was not controlled with benzodiazepines and was electively intubated. At the recommendation of the toxicology service, cyproheptadine, a serotonin receptor antagonist, was administered with improvement in the patient's symptoms. Emergency physicians should be aware of the potential of buprenorphine/naloxone to trigger serotonin syndrome.

Asymmetry in the emotional content of lateralised multimodal hallucinations following right thalamic stroke

The thalamus has been described as a "relay station" for sensory information from most sensory modalities projecting to cortical areas. Therefore injury to the thalamus may result in multimodal sensory and motor deficits. In the present study, a 61-year-old woman suffered a right thalamic cerebral vascular accident (CVA; as evidenced by a computerised tomography [CT] scan). Secondary to this incident, she complained of altered sensations across multiple sensory modalities, including olfactory, visual, auditory, tactile, temperature, and pain sensation. Interestingly, during recovery from the thalamic CVA, the patient reported hallucinations in all the modalities cited above. Multimodal dysaethesias (odd sensations) and hallucinations showed reliable laterality in the affective valence across modalities with positive associations within right hemispace and negative associations within left hemispace. Overall, the results support multimodal role of the thalamus and provide evidence for lateralisation of positive and negative affect within the right and left hemispheres respectively.

Risk of serotonin syndrome with concomitant administration of linezolid and serotonin agonists

Linezolid, an antimicrobial used to treat resistant gram-positive bacteria, can inhibit monoamine oxidase, an enzyme that metabolizes serotonin and other biogenic amines. Inhibition of this enzyme can predispose patients who are concomitantly taking serotonin agonists to serotonin syndrome. Because of the potential of linezolid to inhibit monoamine oxidase, premarketing studies were conducted with drugs such as selective serotonin reuptake inhibitors. No cases of serotonin syndrome were recorded. After linezolid was released to the United States market, several case reports of serotonin syndrome emerged. A literature search revealed 13 cases of serotonin syndrome occurring with the concomitant use of linezolid and drugs possessing serotonergic properties. To direct clinical management of this potential drug interaction, we reviewed reports of serotonin syndrome to determine relevant drug interactions with linezolid and serotonergic drugs and to characterize similarities and differences in the reported cases. Clinicians should obtain complete drug histories to identify patients at risk, strictly monitor drug therapy including concomitant drugs, and receive education about this potential drug interaction and the symptoms of serotonin syndrome.

Parkinsonism–hyperpyrexia syndrome: The role of electroconvulsive therapy

Herein, we present a case of a parkinsonism-hyperpyrexia syndrome (PHS) in a 58-year-old man with a 10-year history of Parkinson's disease. The patient presented with a 2-week history of fever and increasing confusion, in the context of a number of changes to his medication regimen. On presentation, he was noted to be febrile with autonomic instability, diaphoresis and marked rigidity. He was disoriented and responding to visual hallucinations. Investigations revealed an elevated creatine kinase and a provisional diagnosis of PHS was made. After the patient failed to respond during a 2-week period to supportive measures, electroconvulsive therapy (ECT) treatment was commenced. A good response to eight bilateral ECT treatments was achieved, with resolution of his confusional state and associated psychotic phenomena. We discuss the nosological and management issues associated with this case and discuss the role of ECT as a treatment modality in this condition.

Interaction of serotonergic antidepressants and opioid analgesics: Is serotonin syndrome going undetected?

OBJECTIVES

To describe the potential for interaction between opioids and serotonergic antidepressants leading to the development of serotonin syndrome (SS), mechanism of the interaction, and the spectrum of SS in elderly residents of a long-term care facility.

DESIGN

Case series.

SETTING

Long-term care facility (LTCF) in California.

PARTICIPANTS

Four elderly LTCF residents treated with serotonergic antidepressants including selective serotonin reuptake inhibitor (SSRI) or mirtazapine and opioids.

MEASUREMENTS

Signs and symptoms suggestive of SS.

RESULTS

We describe 4 cases of probable SS among elderly residents of a LTCF. The spectrum of serotonin toxicity ranged from visual hallucinations, muscle rigidity, myoclonus, or hypertension in patients taking an opiate with an SSRI to lethargy, hypotension, and hypoxia in a patient taking tramadol and mirtazapine.

CONCLUSION

While many can benefit from coadministration of serotonergic antidepressants and opioids, it appears that some individuals are at increased risk for SS. Since SS is a clinical diagnosis, heightened clinician awareness of the possibility of SS among patients receiving SSRI or mirtazapine in combination with opioids may lead to earlier detection and avoidance of potentially lethal consequences.

Oxycodone

Oxycodone has been in clinical use since 1917. Parenteral oxycodone was used mainly for the treatment of acute postoperative pain whereas combinations, for example, oxycodone and acetaminophen, were used for moderate pain. Since the introduction of controlled-release oxycodone, it has been used to manage cancer-related pain and chronic non-cancer-related pain problems. Controlled studies have been performed in postoperative pain, cancer pain, osteoarthritis-related pain, and neuropathic pain due to postherpetic neuralgia and diabetic neuropathy. The pharmacodynamic effects of oxycodone are typical of a mu-opioid agonist. Oxycodone closely resembles morphine but it has some distinct differences, particularly in its pharmacokinetic profile. Being an old drug, the basic pharmacology of oxycodone has been a neglected field of research.

Factors associated with complex visual hallucinations during antidepressant treatment

Published case reports on complex visual hallucinations (CVH) occurring during antidepressant (AD) treatment were reviewed. Thirteen cases of CVH associated with SSRI treatment, 16 cases during tricyclic drug treatment and seven cases with other AD drug treatments were found. Nine patients were taking concomitant drugs while on therapy with SSRIs and four had a neurological disease in addition to depression. The cholinergic impoverishment occurring in dementia states or during concomitant therapy with anticholinergic drugs could increase the sensitivity to serotonergic agonists, triggering the manifestation of CVH. During tricyclic drug treatment, half of the reports were of hypnopompic or hypnagogic hallucinations and this can be associated with the effects of tricyclics (TCA) on sleep architecture. It is likely that the potent anticholinergic effect of amitriptyline was potentiated in a situation of a rapidly changing state of consciousness. In general, the review supports the view that an imbalance between serotonin and acetylcholine systems is at the root of AD-induced CVH, with a profile defined by a cholinergic hypoactivity and a serotonergic hyperactivity. Caution is needed when administering a combination of serotonergic and anticholinergic AD in the treatment of the demented population and in other already compromised patients because there is a risk of precipitating CVH.