Guide for Improving Adherence to Drug Therapies
Since 1996, the standard treatment for HIV infection has moved from single and double drug therapies to therapies containing three or more anti HIV drugs, also known as Highly Active Antiretroviral Therapy, or HAART. One of the main concerns of antiretroviral programs is to motivate clients to follow their complex drug regimen exactly as prescribed. Unless the therapy is adhered to at least 95 percent correctly, levels of HIV in the blood will rise, resulting in AIDS related complications.
To address this concern, the Population Council's Horizons Program collaborated with the International Centre for Reproductive Health and the Coast Province General Hospital in Mombasa, Kenya, to create a manual for training health care workers in improving patient compliance with antiretroviral therapy "This handbook is one of the first counseling training tools designed to increase adherence to HAART that has been developed in Africa," says Horizons/Population Council researcher Avina Sama, one of the handbook's authors. The manual is being used in an intervention study in Kenya that is investigating ways of improving patients' adherence to HAART.
Introducing Antiretrovirals to Africa
Although 70 percent of individuals worldwide who are infected with HIV live in sub Saharan Africa, antiretroviral treatment programs have only recently arrived there, and most are still on a small scale. Scarce financial resources and poor infrastructure have prevented broader introduction of HAART.
But as the cost of the drugs drops, policymakers, public health officials, and international donors are launching new initiatives to bring antiretroviral treatment to more Africans living with HIV/AIDS.
Patients face significant challenges in following multi-drug antiretroviral therapies precisely. HAART is a life long treatment. While first-line treatment regimens may be available in fixed dose combinations where all medications are contained in one pill, second- and third line regimens often consist of multiple medications that must be taken two to three times a day with vaiying dietary instructions.
Antiretroviral medications also have side effects. Some of these are temporary, but others may last longer and their severity may compel a change of treatment. When patients fail to follow the regimen closely, virus becomes more prevalent in their blood streams, killing their CD4 immune system cells. As a result, opportunistic infections appear, and health suffers.
Additionally, if proper treatment protocols are not followed, the virus can mutate into drug resistant strains.
The manual consists of four training modules for health care workers, each of which takes approximately two hours to complete. The material covered in the workbook includes information on educating the patient about HIV and the HAART regimen, including potential side effects; assessing patient adherence to the protocol; and identifying and overcoming barriers to following the regimen. The manual uses' various techniques to explore these topics: brain storming, small group discussions, PowerPoint presentations, case studies, and role playing.
The Mombasa HAART project, for which the training manual was devised, was initiated in 2003. It was designed as a learning site for similar service delivery programs that are starting up in public health facilities in Kenya and other African countries. The intervention compares two approaches to enhancing patient adherence to the HAART regimen.
One arm of the intervention involves counseling patients, teaching them to use medication diaries and pill boxes, and encouraging them to enlist the help of sympathetic family and friends, among other strategies. The other arm uses all these approaches, but it additionally focuses on modified "directly observed therapy."
Directly observed therapy (DOT) is a treatment strategy originally developed for tuberculosis patients, who must take all their medications consistently and on time for up to nine months to rid themselves of the infection. In the standard DOT approach, health workers or community volunteers literally watch clients as they take their medication.
"DOT has proven to be very effective in helping TB patients maintain their treatment schedules," said Sama. "One big difference between treatments for TB and HIV, though, is that antiretroviral medications for HIV/AIDS must be taken for life."
A DOT strategy for AIDS treatment is called DAART, for "directly administered anti-retroviral therapy." A DAART program includes observation of patients taking their medications, but less often than for TB.
Although it is too early in the study to report findings about long-term adherence, clients in both arms who have completed four to six months of follow up have shown weight gain and increases in the number of CD4 immune system cells that circulate in their blood.
They have also experienced significant improvement in quality of life measures such as physical functioning, cognitive functioning, depression, and pain and energy levels.
Emergency Contraception's Mode of Action Clarified
Emergency contraceptive pills, a hormonal treatment that can prevent pregnancy if taken within 72 hours of unprotected intercourse, have been the subject of heated debate. At issue is the method's mechanism of action: does it prevent the meeting of egg and sperm, or does it prevent a fertilized egg from implanting in the uterus? Recent research by members of the Population Council's International Committee for Contraception Research (ICCR) and other scientists shows that the most popular method of emergency contraception appears to work by interfering with ovulation, thus preventing fertilization, and not by disrupting events that occur after fertilization.
The most common and effective form of emergency contraception contains levo-norgestrel, a progestin. It is sold in the United States and Canada under the name Plan B®. Reproductive physiologist Horacio B. Croxatto of the Chilean Institute for Reproductive Medicine in Santiago, Chile, and his colleagues studied the effects of levonorgestrel on the reproductive cycle of female rats, monkeys, and humans. Croxatto and one of his study partners, biomedical researcher Vivian Brache of PROFAMILIA in Santo Domingo, Dominican Republic, are members of the ICCR.
Emergency Contraception in Animal Studies
Croxatto and his colleagues exposed female rats to very high doses of levonorgestrel at various stages in their reproductive cycle, either before or after ovulation or before or after mating. "When a woman uses emergency contraception," Croxatto explained, "she does not know whether she is taking the pills before or after ovulation or before or after fertilization." The researchers found that levo norgestrel inhibited ovulation totally or partially depending on the timing of treatment and the dose administered. However, the drug had no effect on fertilization or implantation when it was administered shortly before or after mating or before implantation.
Next, Croxatto and his colleagues studied the effects of levonorgestrel given to Cebus monkeys either before ovulation or postcoitally. The reproductive cycle of each animal was monitored by ultrasound examination of the ovaries, vaginal smears, and measurements of blood hormone levels, in order to time the administration of levonorgestrel. The researchers found that, when given before ovulation, levonorgestrel was able to inhibit or postpone ovulation. Alternatively, when it was given after mating at a time when fertilization was believed to have occurred (on the basis of previous monitoring) the pregnancy rates observed were identical in cycles treated with levonorgestrel or with a placebo. This indicates that levonorgestrel did not interfere with any postfertilization process required for embryo implantation.
Emergency Contraception in Women
Women may become pregnant when they have intercourse in the five days before ovulation. This is because sperm can live in the female reproductive system for up to five days. An egg, however, is usually viable for only six to 12 hours after it is released. Croxatto, Brache, and their colleagues studied the effects of levo norgestrel administered during this fertile preovulatory period of women's menstrual cycle.
Twenty nine women in Santiago and 29 women in Santo Domingo were enrolled in the study All of the women were protected from pregnancy by tubal ligation or a nonhormonal intrauterine device. The study was randomized, double blind, and placebo controlled: the gold standard for clinical trials. Women were treated with either placebo, a full dose of Plan B emergency contraception, or a half dose of the drug. They were followed over several cycles and, by the end of the study each woman had received all three of these treatments, separated by resting cycles. The women were randomly assigned to receive the treatments at specific times during the fertile preovulatory period, according to the diameter of the leading ovarian follicle, as determined by ultrasound. The leading ovarian follicle is the structure that ruptures to release the mature egg.
In 82 percent of Plan B-treated cycles, follicles failed to rupture within the five day period following treatment (the maximum time span sperm would survive in the female reproductive tract), or there was some significant ovulatory dysfunction. These conditions occurred in only 41 percent of placebo cycles. The rate of ovulatory dysfunction observed with Plan B treatment is identical with the estimated efficacy rate of Plan B emergency contraception. Blood tests indicated that Plan B affects ovulation by suppressing the surge of luteinizing hormone (LH) that normally acts as a trigger for the ovulatory process.
"There is no doubt that fertilization 'would not have taken place in those women should they have had intercourse prior to treatment," says Croxatto. "We conclude that the effects exerted by Plan B, when it is taken before the onset of the LH surge, may fully explain the pregnancies averted by emergency contraception. Failure to affect the LH surge, because treatment was begun too late in the fertile preovulatory period, explains the 20 per cent failure rate of this method."
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