Precautions and Warnings With Penbutolol
There are numerous precautions and warnings with penbutolol to be aware of before starting treatment. For example, it is important to know that penbutolol may worsen certain medical conditions such as asthma or heart failure. Also, you should not take this medication if you have second- or third-degree heart block, cardiogenic shock, or a very slow heart rate.
You should talk with your healthcare provider prior to taking penbutolol sulfate (Levatol®) if you have:
- Kidney disease, such as kidney failure (renal failure)
- Chest pain (angina)
- Heart failure
- A slow heart rate (bradycardia)
- Heart block
- Chronic obstructive pulmonary disease (COPD)
- An upcoming surgery
- Any allergies, including allergies to food, dyes, or preservatives.
Also, let your healthcare provider know if you are:
- Pregnant or thinking of becoming pregnant
Make sure to tell your healthcare provider about all other medicines you are taking, including prescription and nonprescription medicines, vitamins, and herbal supplements.
Some precautions and warnings to be aware of prior to taking penbutolol include the following:
- As with all beta blockers, you should not abruptly stop taking penbutolol, as serious problems (including heart attacks) may result. Your healthcare provider will advise you about how to safely stop taking this medication. You likely will be advised to slowly reduce the dose over a period of one to two weeks, with careful monitoring, and to minimize physical activity during this time. Let your healthcare provider know if you develop chest pain or any other problems while stopping treatment.
- Beta blockers can worsen breathing problems like asthma or COPD. If you have breathing problems, check with your healthcare provider before taking penbutolol.
- The kidneys remove penbutolol from the body. Therefore, if you have kidney disease, your healthcare provider may need to monitor your response to the medication more closely and a lower dosage may be recommended.
- Like all beta blockers, penbutolol can worsen heart failure in some situations. However, beta blockers are also useful for the treatment of heart failure. If you have heart failure, your healthcare provider may need to monitor you closely while you take this drug. Let your healthcare provider know immediately if your heart failure symptoms seem to become worse.
- If you will be having surgery, make sure your surgeon and anesthesiologist know you take penbutolol, as it may affect the choice of medications used during the procedure.
- Beta blockers can mask some of the symptoms of low blood sugar (hypoglycemia), particularly the "racing heart" feeling. This can cause serious problems for people with diabetes, who need to be able to sense that they have low blood sugar in order to correct it before it becomes life-threatening.
- Beta blockers can mask some of the symptoms of an overactive thyroid (hyperthyroidism). Stopping penbutolol suddenly could cause symptoms of a "thyroid storm" (a sudden and severe worsening of hyperthyroidism symptoms).
- Penbutolol can potentially interact with many other medications (see Drug Interactions With Penbutolol).
- If you have an anaphylactic allergy (the type that affects the entire body and often interferes with breathing), penbutolol may make you more sensitive to the allergen and may make the usual treatments (such as epinephrine or an EpiPen®) less effective.
- Penbutolol is considered a pregnancy Category C medication. This means that it might not be safe for use during pregnancy, although the full risks are not currently known (see Levatol and Pregnancy).
- It is unknown if penbutolol passes through breast milk in humans. Therefore, if you are breastfeeding or plan to start, discuss this with your healthcare provider prior to taking the drug (see Levatol and Breastfeeding).