7.1.1 Primary dysmenorrhoea
- For optimal effect, regular analgesics should be initiated just before anticipated onset of menstruation.
- Offer an NSAID first line unless NSAIDs are contraindicated. Ibuprofen may be preferred because of its more favourable risk-benefit ratio.
- Offer paracetamol first line if NSAIDs are contraindicated or not tolerated, or in addition to an NSAID if the response is insufficient.
- If the woman does not wish to conceive, then hormonal contraceptives should be considered as alternative first line treatment (see section 7.3.1 ) since they may prevent the pain of dysmenorrhoea.
- Combination of an NSAID and/or paracetamol and hormonal contraception is an option for women who do not respond to a single treatment.
- Refer the woman if her symptoms are severe and not responding to initial treatment, or where symptoms are deteriorating with time, or if there is doubt about the diagnosis.
- Some patients may be at increased risk of experiencing toxicity at therapeutic doses of paracetamol, particularly those with a body-weight under 50 kg and those with risk factors for hepatotoxicity. Clinical judgement should be used to adjust the dose of paracetamol in these patients.
- Co‐administration of enzyme-inducing antiepileptic medications and paracetamol may increase toxicity; doses should be reduced.
- There are concerns that mefenamic acid is more likely to cause seizures in overdose than other NSAIDs; mefenamic acid has a narrow therapeutic window which increases the risk of accidental overdose.