The Editorial Executive Committee welcomes letters, which should be less than 250 words. Before a decision to publish is made, letters which refer to a published article may be sent to the author for a response. Any letter may be sent to an expert for comment. When letters are published, they are usually accompanied in the same issue by their responses or comments. The Committee screens out discourteous, inaccurate or libellous statements. The letters are sub-edited before publication. Authors are required to declare any conflicts of interest. The Committee's decision on publication is final.

Letter to the Editor

Editor, – I found your recent article on ‘Sex, drugs and alcohol: drug interactions of concern to consumers’ (Aust Prescr 2013;36:46-8) informative. However, I believe there should be an addition to the box ‘Drugs which can reduce the effectiveness of oral contraceptives’.

Sugammadex is a novel drug used in the reversal of neuromuscular blockade. At least anecdotally, use amongst anaesthetists in private practice is widespread. However, few anaesthetists are aware of its potential interactions with hormonal contraceptives.

A summary of the drug (Aust Prescr 2009;32:82-6) stated that ‘Prescribers need to be aware that sugammadex may decrease progestogen concentrations, similar to the decrease observed after missing a daily dose of an oral contraceptive. Women on the pill should refer to the missed dose advice for their contraceptive. Likewise, women using non-oral hormonal contraceptives, such as depot formulations, should be advised to use additional contraception for the next seven days’.

Jennifer Dixon

Author's comments

Graeme Vernon, the author of the article, comments:

Thank you for highlighting the warnings in the product information. It is not possible to assess the actual risk of this interaction as the warnings are based on chemical tests to determine the degree of binding and pharmacokinetic modelling, rather than evidence of contraceptive failure or reduced serum concentrations of oestrogens or progestogens.

Despite the low level of evidence to support this interaction, the recommended precautions should be taken. However, if sugammadex is being used routinely there should be scope for prospective studies of the actual effects on serum concentrations of contraceptive hormones. This could be an opportunity for regulators and sponsors to resolve an important clinical question and make the product information more clinically meaningful.