BMA Concise Guide to Medicine & Drugs

Gabapentin

Brand name Neurontin

Used in the following combined preparations None

QUICK REFERENCE

Drug group Anticonvulsant drug

Overdose danger rating Medium

Dependence rating Low

Prescription needed Yes

Available as generic Yes

GENERAL INFORMATION

Gabapentin is an antiepileptic drug introduced in 1993. It is used to treat partial seizures, and is often prescribed in combination with other drugs when a patient’s epilepsy is not being satisfactorily controlled with the other drugs alone. Unlike some of the other antiepileptics, gabapentin does not need blood level monitoring. In addition, it does not have any significant interactions with other anticonvulsant drugs.

Gabapentin is also used to relieve neuropathic pain, such as the pain suffered after shingles or by some people with diabetes.

Patients with impaired kidney function should be given smaller doses, and diabetic patients taking gabapentin may notice fluctuations in their blood sugar levels.

INFORMATION FOR USERS

Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Tablets, capsules.

Frequency and timing of doses Dose is gradually built up to 3 x daily as maintenance treatment. No more than 12 hours should elapse between doses.

Adult dosage range 900–3,600mg daily; maintenance dose reached gradually over a few days.

Onset of effect The full antiepileptic effect may not be seen for 48 hours.

Duration of action 6–8 hours.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children.

Missed dose Take as soon as you remember. If your next dose is due within 4 hours, take a dose now and skip the next.

Stopping the drug Gabapentin should not be stopped abruptly. Gradual withdrawal over at least 7 days is advised to reduce the risk of seizures in those being treated for epilepsy.

Exceeding the dose An occasional unintentional extra dose is unlikely to be a cause for concern. Large overdoses may lead to dizziness, double vision, and slurred speech. Notify your doctor.

POSSIBLE ADVERSE EFFECTS

Drowsiness, dizziness, and fatigue are common adverse effects of gabapentin. Discuss with your doctor if they are severe or if muscle tremor, vision disturbances, indigestion, or weight gain occur. If you experience mood changes, hallucinations, or a rash with the drug, contact your doctor immediately.

INTERACTIONS

Antacids containing aluminium or magnesium These may reduce the effect of gabapentin. The drug should not be taken within 2 hours of antacid preparations.

Morphine This may increase gabapentin blood levels.

Urinary protein tests for diabetics False-positive readings have been recorded with some tests. Special procedures are required for diabetics taking gabapentin.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have a kidney problem.

· You have diabetes.

· You have a history of psychiatric illness.

· You are taking other medicines.

Pregnancy The drug is likely to reach the fetus and its effects are unknown. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk, and the effects on the baby are unknown. Discuss with your doctor.

Infants and children Rarely used in children under 6 years. Reduced doses based on body weight are required in children under 12 years.

Over 60 Doses may have to be adjusted to allow for decreased kidney function.

Driving and hazardous work Avoid driving or hazardous work until you have learned how the drug affects you. Gabapentin may produce drowsiness or dizziness.

Alcohol Alcohol may increase the sedative effects of gabapentin.

PROLONGED USE

No problems expected.