7.1.1 Primary dysmenorrhoea


Choice	Drug
1st choice	Ibuprofen tablets 200mg, 400mg, 600mg; syrup 100mg/5ml
		Or
		Naproxen 250mg, 500mg
2nd choice	Paracetamol tablets 500mg; soluble tablets 500mg; oral suspension 120mg/5ml, 250mg/5ml; suppositories 60mg, 125mg, 250mg, 500mg

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.