BNF for Children 2011-2012

404 7.3.2 Progestogen-only contraceptives BNFC 2011–20127 Obstetrics, gynaecology, and urinary-tract disordersIndication and doseContraception. By mouth1 tablet daily at same time each day, starting onday 1 of cycle then continuously; if administrationdelayed for 3 hours (12 hours for Cerazette c ) ormore it should be regarded as a ‘missed pill’, seenotes aboveCerazette c (Organon) ATablets, f/c, desogestrel 75 micrograms, net price 3 28-tab pack = £8.68The Scottish Medicines Consortium has advised (September2003) that Cerazette c should be restricted for use in womenwho cannot tolerate oestrogen-containing contraceptives orin whom such preparations are contra-indicatedFemulen c (Pharmacia) ATablets, etynodiol diacetate 500 micrograms, netprice 3 28-tab pack = £3.31Micronor c (Janssen) ATablets, norethisterone 350 micrograms, net price 3 28-tab pack = £1.66Norgeston c (Bayer Schering) ATablets, s/c, levonorgestrel 30 micrograms, net price35-tab pack = 92pNoriday c (Pharmacia) ATablets, norethisterone 350 micrograms, net price 3 28-tab pack = £2.107.3.2.2 Parenteral progestogen-onlycontraceptivesMedroxyprogesterone acetate (Depo-Provera c )isalong-acting progestogen given by intramuscular injection;it is as effective as the combined oral preparationsbut because of its prolonged action it should never begiven without full counselling backed by the patientinformation leaflet. It may be used as a short-term orlong-term contraceptive for women who have beencounselled about the likelihood of menstrual disturbanceand the potential for a delay in return to fullfertility. Delayed return of fertility and irregular cyclesmay occur after discontinuation of treatment but there isno evidence of permanent infertility. Heavy bleeding hasbeen reported in patients given medroxyprogesteroneacetate in the immediate puerperium; delaying the firstinjection until 6 weeks after the birth may minimisebleeding problems. If the woman is not breast-feeding,the first injection may be given within 5 dayspostpartum (she should be warned that the risk ofheavy or prolonged bleeding may be increased). Themanufacturer advises that in women who are breastfeeding,the first dose should be delayed until 6 weeksafter the birth; however, evidence suggests no harmfuleffect to infant if given earlier. The benefits of usingmedroxyprogesterone acetate in breast-feeding womenoutweigh any risks.Reduction in bone mineral density and, rarely, osteoporosisand osteoporotic fractures have also beenreported with medroxyprogesterone acetate. The reductionin bone mineral density occurs in the first 2–3 yearsof use and then stabilises. See also below.. In adolescents, medroxyprogesterone acetate(Depo-Provera c ) should be used only whenother methods of contraception are inappropriate;. in all women, the benefits of using medroxyprogesteroneacetate beyond 2 years should beevaluated against the risks;. in women with risk factors for osteoporosis, amethod of contraception other than medroxyprogesteroneacetate should be considered.Norethisterone enantate (Noristerat c ) is a long-actingprogestogen given as an oily injection which providescontraception for 8 weeks; it is used as short-terminterim contraception e.g. before vasectomy becomeseffective.An etonogestrel-releasing implant (Nexplanon c ) isalso available. It is a highly effective long-actingcontraceptive, consisting of a single flexible rod that isinserted subdermally into the lower surface of the upperarm and provides contraception for up to 3 years. Themanufacturer advises that in heavier women, bloodetonogestrelconcentrations are lower and therefore theimplant may not provide effective contraception duringthe third year; they advise that earlier replacement maybe considered in such patients, however, evidence tosupport this recommendation is lacking. Local reactionssuch as bruising and itching can occur at the insertionsite. The contraceptive effect of etonogestrel is rapidlyreversed on removal of the implant. The doctor or nurseadministering (or removing) the system should be fullytrained in the technique and should provide fullcounselling reinforced by the patient informationleaflet.Implanon c , also an etonogestrel-releasing implant, hasbeen discontinued (October 2010), but some womenmay have the implant in place until 2013.The cautions, contra-indications, and side-effects of oralprogestogen-only contraceptives apply to parenteralprogestogen-only contraceptives, except that parenteralpreparations reliably inhibit ovulation and thereforeprotect against ectopic pregnancy and functionalovarian cysts.Interactions Effectiveness of parenteral progestogenonlycontraceptives is not affected by antibacterials thatdo not induce liver enzymes. The effectiveness of norethisteroneand medroxyprogesterone acetate intramuscularinjections is not affected by enzyme-inducingdrugs and they may be continued as normal duringcourses of these drugs. However, effectiveness of theetonogestrel-releasing implant may be reduced byenzyme-inducing drugs and an alternative contraceptivemethod, unaffected by the interacting drug, isrecommended during treatment with the enzyme-inducingdrug and for at least 4 weeks after stopping. For ashort course of an enzyme-inducing drug, if a change incontraceptive method is undesirable or inappropriate,the implant may be continued in combination withadditional contraceptive precautions (e.g. condom) forthe duration of treatment with the enzyme-inducingdrug and for 4 weeks after stopping it.