BMA Concise Guide to Medicine & Drugs

Pilocarpine

Brand names Minims Pilocarpine, Pilogel, Salagen

Used in the following combined preparations None

QUICK REFERENCE

Drug group Drug for glaucoma

Overdose danger rating Medium

Dependence rating Low

Prescription needed Yes

Available as generic Yes

GENERAL INFORMATION

Pilocarpine is a miotic drug that is used to treat chronic glaucoma and severe glaucoma prior to surgery. The eye drops are quick-acting, but have to be reapplied every four to eight hours. Eye gel is longer acting and needs to be applied only once a day. Pilocarpine frequently causes blurred vision; and spasm of the eye muscles may cause headaches, particularly at the start of treatment. However, serious adverse effects are rare. Pilocarpine tablets are used to treat dry mouth following radiotherapy to the head and neck, and dry mouth and eyes due to Sjögren’s syndrome (an autoimmune disease).

INFORMATION FOR USERS

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

How taken/used Tablets, eye gel, eye drops.

Frequency and timing of doses Eye drops 4 x daily (chronic glaucoma); 5-minute intervals until condition is controlled (acute glaucoma). Eye gel Once daily. Tablets 3–4 x daily after food with plenty of water.

Adult dosage range According to formulation and condition. In general, 1–2 eye drops are used per application. Tablets 15–30mg daily.

Onset of effect 15–30 minutes.

Duration of action 4–8 weeks for maximum effect (tablets); 3–8 hours (eye drops); up to 24 hours (eye gel).

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children (tablets/eye drops). Discard eye drops 1 month after opening.

Missed dose Use as soon as you remember. If not remembered until 2 hours before your next dose, skip the missed dose and take the next dose now.

Stopping the drug Do not stop the drug without consulting your doctor; symptoms may recur.

Exceeding the dose An occasional unintentional extra application is unlikely to cause problems. Excessive use may cause facial flushing, an increase in the flow of saliva, and sweating. If accidentally swallowed, seek medical attention immediately.

POSSIBLE ADVERSE EFFECTS

The adverse effects of pilocarpine vary according to the form of the drug. Eye drops or gel commonly cause blurred vision, poor night vision, headache, aching of the brow, sweating, chills, and eye pain or irritation. More rarely, they may cause red, watery eyes or twitching of the eyelids. If you experience eye pain or irritation, consult your doctor immediately. For the other symptoms, discuss with your doctor if they are severe. Pilocarpine tablets commonly cause nausea, diarrhoea, dizziness, headache, and frequent urination. Discuss with your doctor if these are severe. If you develop wheezing, stop taking the drug and contact your doctor immediately.

INTERACTIONS

General note A wide range of drugs (including aminoglycoside antibiotics, clindamycin, colistin, chloroquine, quinine, quinidine, lithium, and procainamide) may antagonize pilocarpine.

Beta blockers These drugs may reduce the effects of pilocarpine.

Calcium channel blockers These drugs may increase pilocarpine’s systemic effect.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have asthma.

· You have inflamed eyes.

· You wear contact lenses.

· You have heart, liver, or gastrointestinal problems.

· You are taking other medicines.

Pregnancy No evidence of risk with eye drops at doses used for chronic glaucoma. Safety of tablets in pregnancy not established. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk, but at normal doses adverse effects on the baby are unlikely. Discuss with your doctor.

Infants and children Not usually prescribed.

Over 60 Reduced night vision is particularly noticeable; no dosage adjustment required.

Driving and hazardous work Avoid such activities, especially in poor light, until you have learned how pilocarpine affects you because it may cause short sight and poor night vision.

Alcohol No known problems.

PROLONGED USE

The effect of the drug may occasionally wear off with prolonged use as the body adapts, but may be restored by changing temporarily to another drug.