Injectable contraceptives
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Injectable contraceptives






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Injectable contraceptives Injectable contraceptives Presentation Transcript

  • Introduction
    • Injectable contraceptives contain hormonal drugs that provide women with safe , highly effective , and reversible contraceptive protection .
  • Two types of injectable contraceptives :
    • (1) Progestogen-only formulations that contain a progestogen hormone and are effective for 2 or 3 months; and,
    • (2) Combined formulations that contain both a progestogen and an estrogen and are effective for 1 month
  • Progestogen -only formulations
    • Consist of DMPA (depot med-roxyprogesterone acetate) and NET-EN (norethisterone enanthate).
    • DMPA is the injectable formulation most widely used worldwide .
    • DMPA is injected every 3 months.
    • NET-EN is injected every 2 months.
  • Combined formulations
      • The most extensively studied formulations are known by their brand names, Mesigyna ;
      • Monthly injectable.
      • Mesigyna contains the same progestogen as NET-EN .& contains an added estrogen.
  • Combined formulations
    • Administered by a deep intramuscular injection into the muscle of the arm or buttock and are effective immediately , provided they are taken at specified times
    • All injectable contraceptives are slowly absorbed into the bloodstream from the injection site, with the body maintaining a sufficient level of hormone to provide contraception for 1 to 3 months, depending on the type of injectable used
  • Common trade names Duration of effect Active ingredients Name Depo-Provera, Depo-Clinovir, others 90 days 150 mg medroxyprogesterone acetate in an aqueous microcrystalline suspension DMPA (progestogen-only) Noristerat, Norigest, Doryxas, and others 60 days 200 mg norethisterone enanthate in an oily preparation NET-EN (progestogen-only ) Mesigyna, Norigynon 30 days 50 mg norethisterone enanthate and 5 mg estradiol valerate Mesigyna (combined)
  • Mode of Action
    • The immediate action of progestagen-only injectables (POIs) is to thicken cervical mucus , which then presents an obstacle to sperm penetration.
    • Also, ovulation is impaired .
    • There are additional changes in the endometrium that make it unfavourable to implantation; however, the first two effects make fertilisation highly unlikely.
  • Efficacy
    • The reported failure rates of POIs are low, and come within the narrow range of
    • 0.1% to 0.6%.
  • Beneficial Effects
    • Prevention of pregnancy
    • A single injection of a POI can provide highly effective protection against pregnancy for two or more months, depending on the formulation.
    • Delivery is simple , independent of coitus, and ensures periodic contact with medical or other trained health personnel.
    • This is a suitable method for women in whom oestrogens present health risks – eg, those with a history of thromboembolic disorders - and those who have had side effects with the use of oestrogens.
  • Non-contraceptive health benefits
    • Clear benefits
    • Sickle cell disease: In a two-year trial, women with sickle cell disease using DMPA had significantly fewer crises than women given a placebo.
    • Anaemia: POIs can increase haemoglobin concentration, mainly by reducing menstrual blood loss.
  • Non-contraceptive health benefits
    • Possible benefits
    • 1. Endometrial cancer:
    • In a World Health Organization (WHO) study, women who had ever used DMPA had one-fifth the risk of developing endometrial malignancy observed in women who had not used DMPA.
    • The results, although not statistically significant, support the hypothesis that use of DMPA might protect against this form of cancer.
    • 2. Other:
    • The use of POIs possibly protects against pelvic inflammatory disease (PID), seizures in women with epilepsy, uterine myoma, and endometriosis.
  • Menstrual irregularities
    • DMPA and NET-EN are associated with disruptions of the menstrual cycle including amenorrhoea, prolonged menses, spotting between periods, and heavy bleeding.
    • Less than one-third of women receiving DMPA report having normal menstrual cycles during the first year of use.
  • Menstrual irregularities
    • Amenorrhoea is the most common side-effect and its occurrence increases with duration of use from about 50 % of DMPA users by the end of one year to 80% by the end of 5 years.
    • Women using NET-EN are less likely to experience amenorrhoea.
  • Menstrual irregularities
    • Heavy bleeding is uncommon (occurs in 1-2% of users), and prolonged bleeding is seldom heavy enough to be a threat to health.
    • Any woman who reports prolonged or heavy bleeding may need to be evaluated for anemia .
    • Anaemia treatments include nutritional advice & an appropriate dosage of oral iron tablets .
  • Menstrual irregularities
    • Treatments for heavy bleeding include non-aspirin anti-inflammatory drugs such as ibuprofen, short-term use of combined oral contraceptives or estrogen, or early administration of the next injection (not sooner than 4 weeks after the previous injection).
    • If these measures are not effective or the woman’s health is threatened, POIs should be discontinued.
  • Other Side-Effects
    • After menstrual changes, weight gain, headache, and dizziness are the next most common side-effects reported.
    • Most users of POIs put on weight and this is a common reason for discontinuation.
    • The average DMPA user gains 1.5–2.0 kg in the first year and some users continue to gain weight thereafter at about the same rate.
    • In clinical trials, between 3% and 19% of users of injectables have reported headache or dizziness . Few women discontinue for these reasons.
  • Possible Carcinogenicity
    • Clinical studies have found no association between DMPA use and cervical, ovarian, or liver cancers ,
    • And have confirmed a substantial protective effect against endometrial cancer.
    • Studies have found no overall increase in risk of breast cancer.
    • Although some studies have indicated a small increased risk of breast cancer in some younger women following initial exposure, the studies show no trend toward increased risk among more long-term users.
  • Bone density
    • Findings to date suggest a relatively small and reversible effect , with no serious health risk for women of any age .
    • At present, medical experts recommend no restriction on use of injectables by adolescents over age 16.
    • Changes in calcium uptake by bone and decreases in urinary calcium excretion have been documented and there is a suggestion of a relation between long term use of DMPA and low bone mass.
  • Effect on fetal exposure
    • There are no known adverse effects of fetal exposure to injectables.
    • Studies of teenage children who were exposed to DMPA in utero show no significant differences in health, growth, or sexual development compared to other children.
    • Progestogen-only injectables can be used by breastfeeding women at 6 weeks postpartum without adverse effects on nursing infants.
  • Effect on Metabolism
    • The only metabolic effect of undoubted clinical importance is weight gain .
    • - Minor alterations of lipid metabolism , fluid/nitrogen balance , glucose tolerance , steroid metabolism , and immune function have been recorded but seem to be of no clinical significance.
    • - Fewer data have been published on the metabolic effects of NET-EN, but its effect on most biochemical functions appears to be similar to that of DMPA.
  • Cardiovascular Effect
    • Data are insufficient to indicate whether there is any relation between DMPA use and cardiovascular complications.
    • Results of a WHO study suggest that there is little or no increased risk of cardiovascular disease associated with the use of progestagen-only injectables, although further investigation is needed into a possible increased risk of stroke among women with high blood pressure.
    • Fertility is not impaired after discontinuation of DMPA or NET-EN although its return is delayed .
    • The average time between the last DMPA injection and conception is about nine months , including the three months during which the injection is effective.
    • More than 80% of women become pregnant within one year of discontinuing DMPA and 90% within two years .
    • The few data on NET-EN suggest that fertility returns more quickly with this agent.
  • World Health Organization (WHO) developed eligibility criteria for the use of various contraceptive methods .
    • Category 1 : A condition for which there is no restriction for the use of the contraceptive method.
    • Category 2 : A condition where the advantages of using the method generally outweigh the theoretical or proven risks.
    • Category 3 : A condition where the theoretical or proven risks usually outweigh the advantages of using the method.
    • Category 4 : A condition which represents an unacceptable health risk if the contraceptive method is used.
  • Contra-indications (category 4):
    • POIs should not be used in the presence of:
    • Confirmed or suspected pregnancy
    • Malignant disease of the breast
  • Conditions requiring careful consideration (category 3):
    • POIs should generally not be used in the presence of:
    • Diabetes with vascular disease or of >20 years’ duration
    • Cerebrovascular or coronary artery disease
    • Acute liver disease
    • 4.benign or malignant liver tumours
    • Severe hypertension/ (BP>180/110 mm Hg)
    • Hypertension with vascular disease
    • Focal migraine .
    • severe cirrhosis
  • Other Conditions (category 2)
    • - Women with mild to moderate hypertension, diabetes (without vascular complications), hyperlipidaemias, or mild (compensated) cirrhosis can generally use POIs.
    • - Careful screening and appropriate monitoring will allow the benefits of using POIs to outweigh any potential risks.
  • Mode of Action
    • Combined injectable contraceptives (CICs) exert their contraceptive effect mainly by suppressing ovulation .
    • In addition, thickening of the cervical mucus (mainly due to the progestagen) presents an obstacle to sperm penetration.
    • The receptivity of endometrium to the blastocyst is also reduced.
  • Efficacy
    • In clinical trials, Cyclofem /Cycloprovera and Mesigyna/Norigynon have both proved highly effective contraceptives
    • With 12-month failure rates of 0.2% or less for Cyclofem and 0.4% for Mesigyna .
  • Beneficial Effects
    • A single injection of a CIC can provide highly effective protection against pregnancy for one month .
    • Delivery is simple and independent of coitus, and in general CICs are associated with better cycle control than POIs.
  • Side-Effects
    • In clinical trials, side-effects of CICs included irregular bleeding, amenorrhoea, heavy bleeding, prolonged bleeding, headaches, dizziness, and body weight changes.
    • However, these side-effects are much less common than with the use of POIs.
  • Return of Fertility
    • The return of fertility following CIC use is noticeably shorter than that observed for POIs.
    • More than 50% of women become pregnant within six months of discontinuing CICs and 80% within one year.
  • Eligibility Criteria
    • Until sufficient clinical data become available, the eligibility criteria for the use of combined injectable contraceptives are based on data from combined oral contraceptives
  • Adolescents
    • Injectable contraceptives have important advantages in adolescents; however, in those under 16 years of age there are concerns regarding the hypo-oestrogenic effects of POIs, which may affect the post-menarche increase of bone mineral density.
  • Women Over 35
    • POIs and CICs can be used by most healthy women over 35 .
    • Any increase in risk of cardiovascular disease will be minimal for these women if they do not smoke and have no other risk factors, such as hypertension or diabetes.
  • Postpartum (in Breast feeding Women)
    • If a woman wishes to start injectable contraception during breastfeeding a POI should be recommended .
    • DMPA and NET-EN have no apparent negative influence on milk production or the duration of lactation ; and infants whose mothers have received DMPA while breastfeeding seem to develop normally, both physically and mentally.
  • Postpartum (in Breast feeding Women)
    • The question of possible consequences of the transfer of the injectable steroid to the breastfed infant has yet to be resolved .
    • The amounts of steroid transmitted in the milk and absorbed by the infant are known to be small.
  • Postpartum (in Breast feeding Women)
    • Short-term follow-up studies of children breastfed by mothers using progestagen-only contraceptives have given reassuring results, but longer-term studies are yet to be evaluated.
    • It is recommended that breastfeeding women should not start POIs before the sixth week postpartum .
  • Postpartum (in Breastfeeding Women)
    • There are no data on the effects of CIC formulations on the quantity and quality of breast milk or the duration of lactation.
    • Until such data become available, CICs should generally be withheld until six months after delivery or until the infant is weaned, whichever is the earlier
  • Postpartum (in Non-Breast feeding Women)
    • To avoid increasing the risk of thromboembolic complications in the postpartum period, CICs should not be used during the first three weeks after delivery.
    • After 21 days, blood coagulation and fibrinolysis are essentially back to normal.
    • POIs can be started at any time after delivery .
  • Drug Interaction
    • Drugs that induce liver enzymes may lessen the efficacy of hormonal contraceptives.
    • Such drugs which are commonly used in long-term treatments include the antibiotics rifampicin and griseofulvin and the anticonvulsants phenytoin , carbamazepine , and barbiturates.
  • Prevention of STD/HIV Transmission
    • Strict aseptic techniques should be maintained when giving the injections to avoid the risk of transmitting any infection including HIV.
    • Injectable contraceptives do not protect against STD/HIV infection.
    • Therefore, when there is a risk of sexual transmission of infection, condoms should always be used in addition to injectable contraceptives.
  • Elective Surgery
    • It is advisable to stop using CICs about four weeks before elective surgery that will involve prolonged immobilisation , and to restart them two weeks after the woman has returned to mobility.
    • Alternative effective contraception, including POIs, should be advised during this time.
    • In emergency procedures, the surgeon may consider prophylactic anticoagulant measures
  • Sickle Cell Disease
    • Either POIs or CICs can be used by women with sickle cell disease but POIs are a more suitable choice.
    • In addition to their contraceptive effect, there is some evidence of benefit on the disease itself.
  • Counselling
    • Clients considering the use of injectable contraception should be clearly informed about the advantages and disadvantages of the agents, their side-effects, their cost, and the alternative contraceptive options.
    • Where once-a-month injectables are available, clients should be told about the differences between these injectables and POIs.
    • Women who desire a rapid return to fertility on discontinuation of their contraceptive should be advised to use CICs where available or another method.
  • some misconceptions about injectables
  • Do injectable contraceptives cause infertility ?
    • No.
    • Although a woman's return to fertility can be delayed after injectables are discontinued, injectables do not damage fertility.
  • Do injectable contraceptives increase cancer risks ?
    • No.
    • Overall increase in cancer risk has not been demonstrated in long-term, multicountry studies of injectable users.
  • When amenorrhea occurs, does menstrual blood build up in the body, leading to disease ?
    • No.
    • Amenorrhea is not a  health risk.
    • It does not cause  blood to build up in the body.
  • Can injectable contraceptives transmit disease ?
    • No.
    • Injectable contraceptives are sterile preparations that are free from disease- causing agents.
    • Contaminated needles and syringes used to administer injectables can transmit disease, however .
  • special injection techniques
    • Injectable contraceptives are administered using deep intramuscular injection techniques.
    • The injection site should not be massaged afterwards, since this may accelerate absorption of the drug.
    • Because DMPA is an aqueous suspension, a DMPA vial must be shaken vigorously before it is loaded into the syringe, to resuspend any active ingredient in the bottom of the vial.
    • The syringe should then be checked to ensure that it contains the correct dosage.
    • NET-EN is an oil-based solution that needs special care to ensure that all the solution is both loaded and injected without leakage.
    • Warming the vial to body temperature makes it easier to draw into the syringe.
    • Since Mesigyna is an oil-based solution similar to NET-EN , the same attention to leakage applies.
  • When can the initial injection be given ?
  • Progestogen -Only Injectables
    • DMPA and NET-EN :
    • During the first 7 days of the menstrual cycle.
    • Injectables will be immediately effective.
    • Immediately after abortion.
    • At other times in a menstrual cycle as long as the possibility of pregnancy is ruled out.
    • At 6 weeks postpartum .
  • Combined Injectables Mesigyna
    • During the first 5 days of the menstrual cycle.
    • Injectables will be immediately effective.
    • Immediately after abortion.
    • At other times in a menstrual cycle as long as the possibility of pregnancy is ruled out.
    • At 6 months postpartum .
  • Margin for the follow-up re-injection
    • Progestogen-Only Injectables DMPA and NET-EN: up to 2 weeks (14 days) early or late
    • Combined Injectables Mesigyna:
    • Up to 3 days early or late
  • Breast feeding
    • Progestogen-Only Injectables DMPA and NET-EN:
    • Suitable for women who are breastfeeding at 6 weeks postpartum.
    • Combined Injectables Mesigyna:
    • Not suitable for women who are fully breast feeding until 6 months postpartum.
  • Thank you