Calan SR (verapamil) is a calcium channel blocker used to treat hypertension, angina, supraventricular tachycardia, migraines, and cluster headaches. It can be used in patients age 16 and up.

The medication is thought to work by relaxing and slowing the heart, while also relaxing and dilating blood vessels, which lowers blood pressure and reduces the heart's workload. The mechanism by which it works in treating migraines and cluster headaches is not clear.

Note that the SR in this product stands for sustained release, meaning tablets need be taken just once or twice per day. Regular Calan tablets, taken two or three times per day, are available here. Calan SR tablets must be swallowed whole; regular Calan capsules can be mixed into soft foods if desired.

What to Expect from Calan SR

Calan SR may be prescribed when a person has one or more of several ailments:

• Hypertension (high blood pressure)
• Angina (chest pain)
• Supraventricular tachycardia (rapid heartbeat)
• Migraine headaches (preventative only)
• Cluster headaches (preventative only)

The medication is generally not prescribed in patients who have:

• Hypotension (low blood pressure)
• Left ventricular dysfunction in the heart
• Cardiogenic shock

The lowered heart rate and dilation of blood vessels reduce blood pressure and improve blood flow. Lowered heart rate also addresses supraventricular tachycardia, in which the heart beats too fast. Angina, typically caused by insufficient blood flow to the heart muscle, is also alleviated by the improved blood flow. While the exact mechanism behind treating migraine and cluster headaches is unclear, the medication does provide benefit in most cases.

In many conditions Calan SR treats, it is preventative---reduces the frequency and severity of angina, migraines, and cluster headaches. The medication provides little benefit if these conditions flare up; users will still need to utilize other rescue medications, such as nitroglycerin for angina or triptan medications for migraine or cluster headache pain, when they do flare up. As it takes several weeks to see the full benefit of Calan SR, having rescue treatments available will be especially beneficial at the start of treatment.

After several weeks of treatment at an appropriate dose full benefit should be seen. Blood pressure and heart rate should be lower; angina, migraines, and cluster headache frequency should be dramatically reduced, if they occur at all.

Taking Calan SR

Treatment with Calan SR is quite similar in all cases; the medication is taken daily over the long term. Other medications may or may not be involved. Personal variables, such as age and weight, can influence dosage levels, as will patient response to treatment.

In otherwise healthy adults, standard treatment is typically:

• Take 180 mg per day in the morning.
• Tablets should be swallowed whole and taken with food.

The initial dose may need to be adjusted; effects should be checked after one week of treatment for hypertension, perhaps longer---three to four weeks---for other conditions. If adjustments are needed there are several options:

• Take 240 mg once per day in the morning; or
• Take 180 mg in the morning and 180 mg in the evening; or
• Take 240 mg in the morning and 120 mg in the evening; or
• Take 240 mg every 12 hours.

Higher doses---more than 240 mg total per day---are typically reserved for heart conditions. For migraines and cluster headaches treatment is more likely 240 mg per day or less, though there may be exceptions. Patients taking Calan SR will likely need frequent heart and blood pressure tests until the ideal dosage is established, regardless of why it's being taken.

Calan SR can significantly extend and improve a patient's life by lowering blood pressure, regulating heartbeat, and reducing the frequency of angina, migraines, or cluster headaches---all of these things can have a dramatically negative impact if left untreated.