Interaction between clonidine and escitalopram

[Validation of interaction databases in psychopharmacotherapy]

BACKGROUND

Drug-drug interaction databases are an important tool to increase drug safety in polypharmacy. There are several drug interaction databases available but it is unclear which one shows the best results and therefore increases safety for the user of the databases and the patients. So far, there has been no validation of German drug interaction databases.

GOAL

Validation of German drug interaction databases regarding the number of hits, mechanisms of drug interaction, references, clinical advice, and severity of the interaction.

METHODS

A total of 36 drug interactions which were published in the last 3-5 years were checked in 5 different databases. Besides the number of hits, it was also documented if the mechanism was correct, clinical advice was given, primary literature was cited, and the severity level of the drug-drug interaction was given.

RESULTS

All databases showed weaknesses regarding the hit rate of the tested drug interactions, with a maximum of 67.7% hits. The highest score in this validation was achieved by MediQ with 104 out of 180 points. PsiacOnline achieved 83 points, arznei-telegramm® 58, ifap index® 54 and the ABDA-database 49 points. Based on this validation MediQ seems to be the most suitable databank for the field of psychopharmacotherapy.

DISCUSSION

The best results in this comparison were achieved by MediQ but this database also needs improvement with respect to the hit rate so that the users can rely on the results and therefore increase drug therapy safety.

Using Selective Serotonin Reuptake Inhibitors and Serotonin-Norepinephrine Reuptake Inhibitors in Critical Care: A Systematic Review of the Evidence for Benefit or Harm

OBJECTIVE

Selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitors are among the most commonly prescribed drugs in patients admitted to the ICU. Our objective was to systematically review available literature for evidence of benefit or harm in ICU patients resulting from chronic effects, continued use, or withdrawal.

DATA SOURCES

Medline, Embase, and Cochrane Central Register of Controlled Trials (1990 to November 2014).

STUDY SELECTION

We searched for studies of ICU patients with recorded selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitor prescription before or during admission, and reporting morbidity, mortality, adverse events, and resource measures like ICU length of stay. We considered all study designs. We excluded studies of deliberate overdose and depression in non-ICU settings. Two authors independently and in duplicate screened citations and reviewed text of studies to apply selection criteria.

DATA EXTRACTION

Two authors abstracted data on patient characteristics in exposed and control groups; use of selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitors previously or during ICU; comparator intervention; and outcomes, and also assessed methodologic quality.

DATA SYNTHESIS

The database search retrieved 4,172 unique citations, of which 289 were reviewed, and 13 studies representing a total of 20,048 patients met selection criteria. There were five cohort studies, one case series, and seven case reports. Only one case report suggested benefit from selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitor use and 11 studies reported morbidity in patients using these medications at admission to ICU. However, due to inadequate drug administration reporting, it was generally unclear if outpatient selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitors were continued in ICU, complicating interpretation.

CONCLUSIONS

There may be excess morbidity in critically ill selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitor users, but uncertainty remains whether this is due to chronic effects, ongoing use, or drug withdrawal. Further research with improved standards of drug administration reporting is needed to help clinicians decide when to use selective serotonin reuptake inhibitor/serotonin-norepinephrine reuptake inhibitors in critically ill patients.

Determination of pharmacological interactions of uliginosin B, a natural phloroglucinol derivative, with amitriptyline, clonidine and morphine by isobolographic analysis

Uliginosin B is a natural phloroglucinol derivative, obtained from Hypericum species native to South America. Previous studies have shown that uliginosin B presents antidepressant-like and antinociceptive effects. Although its mechanism of action is still not completely elucidated, it is known that it involves the activation of monoaminergic neurotransmission. The aim of the current study was to further investigate the antinociceptive mechanism of action of uliginosin B by combining it with different drugs used for treating pain in clinical practice. The intraperitoneal administration of uliginosin B, morphine, amitriptyline and clonidine, alone or in mixture, produced a dose-dependent antinociceptive effect in the hot-plate assay in mice. The effect of the mixtures of drugs was studied using an adapted isobologram analysis at the effect level of 50% of the maximal effect observed. The analysis showed that the interactions between uliginosin B and morphine was synergistic, while the interactions between uliginosin B and amitriptyline or clonidine were additive. These findings point to uliginosin B as a potential adjuvant for pain pharmacotherapy, especially for opioid analgesia.

Clinically significant drug interactions with newer antidepressants

After the introduction of selective serotonin reuptake inhibitors (SSRIs), other newer antidepressants with different mechanisms of action have been introduced in clinical practice. Because antidepressants are commonly prescribed in combination with other medications used to treat co-morbid psychiatric or somatic disorders, they are likely to be involved in clinically significant drug interactions. This review examines the drug interaction profiles of the following newer antidepressants: escitalopram, venlafaxine, desvenlafaxine, duloxetine, milnacipran, mirtazapine, reboxetine, bupropion, agomelatine and vilazodone. In general, by virtue of a more selective mechanism of action and receptor profile, newer antidepressants carry a relatively low risk for pharmacodynamic drug interactions, at least as compared with first-generation antidepressants, i.e. monoamine oxidase inhibitors (MAOIs) and tricyclic antidepressants (TCAs). On the other hand, they are susceptible to pharmacokinetic drug interactions. All new antidepressants are extensively metabolized in the liver by cytochrome P450 (CYP) isoenzymes, and therefore may be the target of metabolically based drug interactions. Concomitant administration of inhibitors or inducers of the CYP isoenzymes involved in the biotransformation of specific antidepressants may cause changes in their plasma concentrations. However, due to their relatively wide margin of safety, the consequences of such kinetic modifications are usually not clinically relevant. Conversely, some newer antidepressants may cause pharmacokinetic interactions through their ability to inhibit specific CYPs. With regard to this, duloxetine and bupropion are moderate inhibitors of CYP2D6. Therefore, potentially harmful drug interactions may occur when they are coadministered with substrates of these isoforms, especially compounds with a narrow therapeutic index. The other new antidepressants are only weak inhibitors or are not inhibitors of CYP isoforms at usual therapeutic concentrations and are not expected to affect the disposition of concomitantly administered medications. Although drug interactions with newer antidepressants are potentially, but rarely, clinically significant, the use of antidepressants with a more favourable drug interaction profile is advisable. Knowledge of the interaction potential of individual antidepressants is essential for safe prescribing and may help clinicians to predict and eventually avoid certain drug combinations.

Unexplained high fever in an elderly patient treated with clonidine, duloxetine, and atorvastatin

BACKGROUND

Drug-induced fever is a clinical diagnosis and should always be considered when the fever is constant and high without a clear source of infection. Although drug-induced fever has been reported with other centrally acting antihypertensive drugs such as methyldopa, published reports of this adverse effect with clonidine in humans were not identified in a search of the literature.

CASE SUMMARY

A 66-year-old institutionalized white female with a history of morbid obesity (body mass index, 40 kg/m2), Alzheimer's dementia, hypertension, and depression presented to a hospital in Boston, Massachusetts (Caritas Saint Elizabeth's Medical Center) with generalized weakness and shortness of breath and was found to have a non-ST segment elevation myocardial infarction. Before hospitalization, the patient was taking memantine 10 mg PO BID, donepezil 10 mg PO once daily, duloxetine 60 mg PO once daily, clonidine 0.1 mg PO TID, metoprolol 50 mg PO BID, and amlodipine 10 mg PO once daily. On admission, the patient was initiated on aspirin 325 mg, atorvastatin 80 mg, and clopidogrel 75 mg PO daily. Her dose of clonidine was increased to 0.2 mg PO TID to optimize blood pressure control, and metoprolol and amlodipine were continued at the same doses. The patient developed fever on the third day after the cardiac catheterization. The fever ranged from 99.0 degrees F to 102.7 degrees F. The physical examination, laboratory data analysis, multiple blood cultures, urinalysis, chest radiograph, and a computed tomography of the head, chest, abdomen, and pelvis did not reveal any source of infection. On the sixth day after admission, clonidine was reduced to the baseline dose of 0.1 mg PO TID and on the ninth day it was stopped. The patient was afebrile on the twelfth day and remained so for the duration of her hospitalization. Naranjo scores for her newly initiated concomitant medications were as follows: aspirin, 1; atorvastatin, 3; clonidine, 6; and clopidogrel, 1. The rating of 6 for clonidine suggests that it was probably associated with the fever in this patient.

CONCLUSION

We describe a case of drug-induced fever probably associated with clonidine administration. The higher dose of clonidine alone or in interaction with duloxetine and atorvastatin may have contributed to the development of drug-induced fever.