Yes, if you use Primidone for a long time, you may become dependent on it. Moreover, stopping the medicine suddenly may also lead to withdrawal symptoms. Therefore, you must inform your doctor before stopping the Primidone.

Do not stop taking Primidone even if you are feeling well, unless your doctor advises so. Suddenly stopping Primidone may cause unwanted effects commonly known as withdrawal symptoms. To prevent this, the dose of Primidone needs to be reduced gradually before completely stopping it.

Inform your doctor if you are taking any other medicines including medicines for epilepsy or seizures, medicines used to thin your blood (e.g., warfarin), birth control pills, medicines to control bacterial infection (e.g., chloramphenicol, metronidazole, and doxycycline), medicines to control viral infection (e.g., nelfinavir), and asthma medicines (e.g., theophylline and montelukast), etc. Also, inform your doctor if you are planning to become pregnant or are breastfeeding. Further, you should tell the doctor if you have ever had liver problems, kidney problems, lung problems, or porphyria (a rare blood pigment disorder).

If Primidone makes you feel sleepy, avoid driving or operating heavy machinery. Alcohol consumption should be avoided since taking both together may cause excessive sleepiness. You should avoid getting pregnant since Primidone is associated with an increased risk of abnormalities in babies.

Severe allergic reactions, skin reactions, abnormalities in blood cells, and worsening of seizures are some of the serious side effects of Primidone. Severe allergic reactions may result in difficulty in breathing, swelling of the lips, tongue, face, or hives. Skin reactions may cause redness, pain, ulcers, blisters, shedding the outer layer of skin. If you have an abnormality of the blood cells, your skin may appear pale. Additionally you may suffer from abnormal bleeding or frequent bruising, fever, or sore throat.

Though headache is not a very common side effect of Primidone, it can occur in a few patients.

No, Primidone does not have any effect on blood pressure.

While taking propranolol and Primidone together, your blood pressure should be monitored as Primidone may interfere with working of propranolol. Your doctor may modify your dose if needed.

Keep it in a cool dry place where the temperature stays below 25°C. Do not leave it on a windowsill or in the car on hot days. Keep it out of reach of children.