Intermittent Patch Research Articles

A randomised-controlled pilot study using nicotine patches with pregnant women

Stopping smoking in pregnancy is a public health priority and a clinical imperative. However, many women who have not been able to ‘quit’ in early pregnancy find it very difficult to do so. This randomised-controlled pilot study examined feasibility issues in offering free nicotine patches with counselling to a group of 20 mid-trimester pregnant women at the Women's and Children's Hospital, Adelaide. A further 20 were offered counselling only. Smoking status at each visit was measured by self-report, carbon monoxide monitoring, and salivary cotinine. The most common pattern (eleven of the twenty women) was intermittent patch use. Only five women used patches continuously up to the 12 week maximum available. Three women in the patch group were abstinent at delivery compared with none in the control group. Notable features of the study were the low interest in participation and the high withdrawal rate. Nicotine patches may not be highly useful for pregnant women. Continuing tobacco control measures and customized support for women and their partners, often smokers, may prove more fruitful.

Efficacy of Long-Term Administration of Transdermal Nitroglycerin in Asymptomatic Patients with Effort-Induced Silent Myocardial Ischemia

The aim of our study was to investigate the effect of transdermal nitroglycerin (NTG) on effort-induced silent myocardial ischemia in asymptomatic patients treated with beta-blockers or calcium antagonists. The acute effect was compared to two different schedules, continuous (24 h/day) or intermittent (16 h/day), of long-term administration. Ten asymptomatic patients with coronary artery disease and a treadmill test positive for ischemia without angina were enrolled. Both acute (2 days) and long-term (24 days) evaluations were conducted in a randomized, double-blind, crossover fashion. The ergometric parameters were collected on the 1st and the 2nd day of the acute phase (placebo and transdermal NTG, respectively) and at the end of each 12-day period of long-term administration (continuous and intermittent, respectively). Transdermal NTG administration acutely increased (p < 0.05) both time to 1-mm ST segment depression (451 +/- 43.2 vs. 374 +/- 24.1 s) and total exercise time (561.3 +/- 43.2 vs. 419.5 +/- 24.5 s). The acute efficacy was maintained over long-term treatment, regardless of the modality of administration. During continuous and intermittent patch application, time to 1-mm ST segment depression was 437.9 +/- 30.4 and 422 +/- 33.4 s (p = NS vs. acute) and total exercise time was 498.8 +/- 30.4 and 495.1 +/- 33 s (p = NS vs. acute), respectively. Transdermal NTG increases, both acutely and chronically, exercise tolerance in asymptomatic patients with effort-induced silent myocardial ischemia. With the NTG dose we used, tolerance does not seem to be a problem over long-term administration.

Transdermal Nitroglycerin (Glyceryl Trinitrate)

Nitroglycerin (glyceryl trinitrate) has been used for many years via the sublingual route for treating acute anginal attacks. In recent years transdermal delivery of nitroglycerin has gained popularity for prophylaxis against angina. However, nitrate tolerance appears to be a therapeutic problem with all long-acting nitrates regardless of delivery mechanism, and it occurs in most patients with stable angina treated with continuous 24-hour application of nitroglycerin patches. Since continuous 24-hour plasma concentrations of nitroglycerin do not appear to be desirable, alternative approaches to therapy are needed. A simple method to minimise tolerance with transdermal nitroglycerin patches is to remove the patch at bedtime and reapply a new patch in the morning. Such intermittent therapy allows a patch-free period during the night, when most patients experience few angina attacks, but optimises nitrate sensitivity during the daytime. However, the place of intermittent nitroglycerin patch therapy in the treatment of stable angina needs clarification with further study, particularly comparisons with other long-acting forms of nitrates. There are insufficient data to recommend the use of transdermal nitroglycerin patches in the treatment of patients with unstable angina or congestive heart failure. In conclusion, transdermal nitroglycerin patches offer a convenient and cosmetically acceptable dosage form which has potential use in stable angina if administered as an intermittent regimen providing a patch-free period each night.

Prevention of tolerance to nitroglycerin patches by overnight removal

This investigation assesses the extent of tolerance development with nitroglycerin patches and whether tolerance might be prevented by overnight patch removal. On commencing therapy, active patches significantly prolonged exercise time (3.5 hours after patch application) in comparison with placebo, with an accompanying reduction in ST-segment depression at maximal common workload. Patients then received continuous or 12-hour-daily intermittent patch therapy, in a double-blind fashion, for 7 days. Exercise testing was repeated before and after active patch application, on the eighth day of each treatment phase. During continuous therapy, beneficial effects on exercise time and ST depression were abolished. By contrast, during intermittent therapy, prolongation of exercise time and reduction in ST-segment depression still occurred, on testing 3.5 hours after active patch application. These results confirm previous studies showing a high degree of tolerance during continuous therapy with nitroglycerin patches and suggest that tolerance can be prevented by 12-hour-daily intermittent therapy.