Injectables Tomorrow: Subcutaneous DMPA and Home Injection
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Illustration: A new lower-dose formulation of DMPA is injected under the skin rather than in the muscle. In developing countries it will be available in prefilled Uniject devices, possibly by 2008. Many women may choose to give themselves the subcutaneous injection or have family members give the injection. Illustration: Rafael Avila/CCP
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A new lower-dose formulation of DMPA, depo-subQ provera 104 (also called DMPA-SC), is injected under the skin rather than in the muscle. It contains 104 mg of DMPA rather than the 150 mg in the intramuscular formulation. Like the intramuscular formulation, DMPA-SC is given at 3-month intervals.
Approved first in the United States and the United Kingdom, subcutaneous injection of DMPA may be available in some developing countries by 2008. DMPA-SC is available only in prefilled, single-use syringes. In developing countries it will be available only in prefilled UnijectTM devices designed for subcutaneous injection (102, 103).
DMPA-SC is just as effective as the formulation injected into the muscle, and the patterns of bleeding changes and amount of weight gain are similar (7, 87). One-year continuation rates in clinical trials were high, 68% on average at sites in North and South America and 80% in Europe and Asia. Despite the lower dose, DMPA-SC is effective for overweight or obese women (41).
Injections of DMPA-SC are given in the upper thigh or abdomen. DMPA-SC should not be injected intramuscularly, and the intramuscular formulation should not be injected subcutaneously. The intramuscular formulation cannot be diluted to make the lower-dose subcutaneous formulation.
Given the choice, many women prefer self-injections or home injection. In trials of DMPA-SC, some women gave themselves injections and many said they would prefer self injection. For example, among 1,787 women participating in trials of DMPA-SC with standard syringes, 16% gave themselves injections. Among the approximately 1,600 participants who answered a questionnaire, most would prefer to give themselves the injection either at home (50%) or in a doctor's office (21%), while 29% would prefer injections by a provider (42). Even with intramuscular injections, most women in small studies of Cyclofem in Brazil and the United States preferred self-injection in the clinic or at home (11, 184). Self-injection of DMPA-SC may require approval by drug regulatory agencies and ministries of health.
Self-injection will save women the time and expense of repeated visits to a health care provider and could increase continuation rates. Among 111 women who stopped using Cyclofem or DMPA in a study enrolling 360 women in Kenya, for example, 43% said the reason was related to problems returning to the clinic on time (165). Women could be given several Uniject devices at the clinic so that they could have home injections for a year or more, or they could buy the devices at a pharmacy.
Women or family members will need training to give injections. Training in Brazil to use Uniject for intramuscular injection of Cyclofem included several sessions under the supervision of a nurse. Women learned how to use the Uniject device, and they practiced giving injections in oranges. More than 90% of the participants learned to give themselves injections correctly (11).
Some women will not want to give themselves injections. In Brazil 102 Cyclofem users were invited to participate in the study of self-injection. Of these, 14 declined because they did not want to give themselves injections, 32 balked at giving themselves injections even after training, and 7 gave themselves one injection but no more, because of pain. The remaining 49—slightly less than half—gave themselves two or three injections (11).
Thus, while self-injection may become an option, it should not be required of everyone. Those who are fearful or hesitant may put off giving themselves an injection and thus increase the chances of pregnancy. Among people with diabetes or multiple sclerosis who give themselves daily or weekly therapeutic injections, anxiety reduces adherence to injection schedules (116, 117).
Self-service offers possible savings and will need guidelines. Home injection will decrease cost per client because self-service clients need less time with health care providers. Still, community providers will need to check periodically for problems with side effects, adherence to the injection schedule, and changes in health that would make switching to another method advisable. Providers will also need to ensure that women dispose of used injection equipment safely. A study of 100 diabetic patients in Tunisia reported that 94% threw used equipment in the household garbage (39). Family planning programs may want to develop guidance, including information on storage of injectable contraceptives and safe disposal of Uniject for women who choose self-injection and for the providers who serve them.
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