eLetters

4 e-Letters

published between 2018 and 2021

  • Response to Van den Eynde and Gillman's letter

    I) We agree with Dr. Van den Eynde that since tedizolid is a more potent inhibitor than linezolid, it is administered at lower doses. Thus, the MAO inhibition would be lower. This is probably the reason why there have been no reports regarding serotoninergic toxicity. However, the possibility of MAO inhibition cannot be ruled out, especially when tedizolid is administered together with serotoninergic drugs. We would like to emphasize that the spontaneous reporting of suspected adverse reactions is useful to identify potential signals that suggest a causal association between a medicinal product and a previously unknown reaction. Whether this suspected adverse reaction is a signal, it should be confirmed by further reports.

    II) In our article we do not affirm that it is a serotonin syndrome or a serotonin toxicity, since, in fact, we do not have enough clinical information to confirm it. We only discuss the possibility that the hypertensive crisis could be related to the co-administration of tedizolid and other serotoninergic drugs. Our position is well defined in the following paragraph of the article: “The causality of hypertension as an adverse drug reaction due to the co-administration of tedizolid and other serotonergic treatments was evaluated using the algorithm of Naranjo et al, obtaining a final score of 3. According to this value, the relationship between tedizolid and the hypertensive crisis should be classified as possible, as we were not able to rule ou...

    Show More
  • A critical appraisal

    We note, upon critical appraisal of this case report, two shortcomings:
    (I) the authors provide a one-sided and inaccurate extrapolation to clinical practice from the literature data on tedizolid;
    (II) the authors do not adhere to well-established ‘diagnostic decision rules for serotonin toxicity’: the Hunter criteria.<1>
    I. In gauging the MAO-inhibiting potential of both antibiotics, de Castro Julve et al. rightly note that ‘tedizolid appears to be a more potent inhibitor in vitro of MAO-A than linezolid’ <2>– but neglect to mention (a) that tedizolid is also four to sixteen (or – depending on the source – ‘two to eight’)<3> times more potent than linezolid at treating most gram-positive infections;<4> and (b) that tedizolid is therefore administered at a lower dose than is linezolid (200mg/day vs. 600mg/12 hours).<3> This likely leads, in practice, to less tedizolid-induced (vs. linezolid-induced) MAO-inhibition<3>, as evidenced by the clinically insignificant potentiation of the tyramine pressor response (TYR30)<2>, and to less potential for serotonergic drug interactions<5>, as further evidenced by the fact that no changes in the murine head twitch response occur, even at plasma tedizolid concentrations which exceed – ‘by up to ~25-fold’ – the Cmax observed in humans at the clinical dose of 200mg/day.<3>
    II. The detection in their patient of a hypertensive crisis ‘suspected to be an adverse r...

    Show More
  • Correction to 2012 legal change

    The section in this paper which says pharmacists could prescribe controlled drugs from 2012 with the exception of schedule 1 and 2 CDs for drug misuse is misleading. Schedule 1 cannot be prescribed by anyone without out a licence to do so (this includes doctors) and schedule 1 contains substances of no medicinal use. Schedule 2 CDs can be prescribed by pharmacists for drug misuse, the only exception is diamorphine (and technically cocaine and dipipanone although these are not used). Diamorphine is prescribed as an injectable by prescribers on the Dept of Health approved list to do so and this list is restricted to medical doctors. Other schedule 2 drugs for addiction such as methadone and morphine (unlicensed) can be prescribed by pharmacist prescribers.

  • Some issues with dose administration aids/monitored dosage systems

    Monitored dosage systems (or dose administration aids) are widely used but it is important to reduce their inappropriate use by ensuring they are only issued on a case-by-case basis to address specific practical problems of medicines adherence. It should be assumed that patients can manage their medicines unless indicated otherwise. NICE guidance (1) states monitored dosage systems should be considered as an option to improve adherence on a case-by-case basis, and only if there is a specific need to overcome practical problems. This should follow a discussion with the patient to explore possible reasons for nonadherence and the options available to improve adherence, if that is their wish.
    • The inappropriate use of monitored dosage systems can make patients and carers less familiar with their medicines. Health literacy including awareness of medicines should be promoted.
    • Transferring medicines to monitored dosage systems carries the risk of human error. The stability of many medicines cannot be guaranteed outside their original packaging.
    • Patients who may benefit from monitored dosage systems include patients who have less ability to read or understand the instructions on standard medicines packaging, but who have the dexterity to use the devices and who wish to adhere to their medicines regimen.
    • Pharmacists should check compliance issues and provide a monitored dosage system only if compliance cannot be addressed by other methods a...

    Show More