An older adult client who is taking doxazosin (Cardura) for hypertension is given a prescription of sildenafil for erectile dysfunction. The nurse should caution the client about which effect?

Question

1. Sildenafil causes rapid elimination of doxazosin through the kidneys.
2. Sildenafil will potentiate the hypotensive effects of doxazosin.
3. Sildenafil blocks the absorption of doxazosin from the gastrointestinal tract.
4. Sildenafil causes hypertension, counteracting the effect.

Answer 1

Correct Answer: 2
Rationale 1: Sildenafil (Viagra) has no effect on the elimination of doxazosin.
Rationale 2: Use of doxazosin (Cardura) with erectile dysfunction agents such as sildenafil (Viagra) can cause increased hypotension, since both these drugs relax the smooth muscles of the vessels. Using both together can cause added hypotension.
Rationale 3: Sildenafil (Viagra) has no effect on the absorption of doxazosin through the gastrointestinal tract.
Rationale 4: Sildenafil (Viagra) does not cause hypertension but hypotension, due to relaxation of the smooth muscle.
Global Rationale: Use of doxazosin (Cardura) with erectile dysfunction agents such as sildenafil (Viagra) can cause increased hypotension, since both these drugs relax the smooth muscles of the vessels. Using both together can cause added hypotension. Sildenafil (Viagra) has no effect on the elimination of doxazosin; no effect on the absorption of doxazosin through the gastrointestinal tract; and does not cause hypertension but hypotension, due to relaxation of the smooth muscle.