7.1.1 Primary dysmenorrhoea

ChoiceDrugDosage
1st choiceIbuprofen tablets 200mg, 400mg, 600mg; syrup 100mg/5mlDose:
Initially 300–400mg 3–4 times daily; increased if necessary to max 2.4g daily; maintenance dose of 600mg–1.2g daily may be adequate
Or
Naproxen 250mg, 500mg Dose:
500 mg initially, then 250 mg every 6–8 hours as required; max. dose after first day 1.25g daily
2nd choiceParacetamol tablets 500mg; soluble tablets 500mg; oral suspension 120mg/5ml, 250mg/5ml; suppositories 60mg, 125mg, 250mg, 500mgDose:
500mg–1g every 4–6 hours; max 4g daily

Prescribing Notes

  • 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.

Cautions

  • 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.