Final answer:
Drugs such as magnesium sulfate, nifedipine, and terbutaline are contraindicated for use as tocolytics in patients with tachy-sensitive maternal cardiac diseases and poorly controlled diabetes due to their impacts on heart functions and glucose control.
Step-by-step explanation:
The contraindications for tocolytics, which include Tachy-sensitive maternal cardiac disease and poorly controlled diabetes, would primarily exclude drugs that could exacerbate these conditions. For patients with these contraindications, the use of magnesium sulfate, nifedipine, and terbutaline can be particularly concerning. Magnesium sulfate and nifedipine are both negative inotropic agents, which can reduce the strength of heart contraction and may not be suitable for those with certain cardiac diseases. Terbutaline, while not a negative inotropic agent, can increase the heart rate, and thus may not be suitable for those with tachy-sensitive disorders. Additionally, drugs like indomethacin can affect blood sugar control, making them a poor choice for people with poorly controlled diabetes.
Considering the contraindications mentioned, we must avoid specific tocolytic agents. Indomethacin, as a nonsteroidal anti-inflammatory drug (NSAID), is also not recommended in these cases due to the potential for adverse effects on the fetal cardiovascular system when used in the third trimester and possible impacts on maternal and fetal renal function.