Side Effects of Robinul (glycopyrrolate)

Robinul (glycopyrrolate) is an anti-cholinergic used to prevent secretions during surgery, reverse neuromuscular blockage, or may be used intraoperatively to counteract surgically or drug-induced irregular heart rate. It is also used in adults as adjunctive therapy to treat a peptic ulcer when rapid anticholinergic effect is desired or when oral medication is not tolerated.

Robinul works by blocking acetylcholine activity on smooth muscles and other tissues. Acetylcholine is a neurotransmitter, a chemical that nerves use for communicating. 

Blocking acetylcholine leads to decrease in volume and acidity of stomach secretions and decrease in pharyngeal, tracheal, and bronchial secretions. It also reverses symptoms of excessive bronchial secretions, bronchospasm, low heart rate, and intestinal hypermotility caused by medications that increase the action of acetylcholine. 

Common side effects of Robinul include

• dry mouth,
• blurred vision,
• dilated pupils,
• increased heart rate,
• sweating,
• weakness,
• dizziness,
• dry skin, and
• constipation.

Serious side effects of Robinul include

• severe constipation,
• severe stomach pain and bloating,
• diarrhea,
• painful or difficult urination,
• fast or pounding heartbeats,
• confusion,
• severe drowsiness,
• eye pain,
• seeing halos around lights,
• fever,
• shallow breathing,
• weak pulse,
• hot and red skin, and
• (in a child taking glycopyrrolate) dry diapers, fussiness, or excessive crying.

Drug interactions of Robinul include anti-cholinergic drugs such as phenothiazines, Parkinson's drugs, or tricyclic antidepressants because the combination can significantly increase anticholinergic side effects like pupil dilation, high blood pressure (hypertension), flushing, fever, and increased heart rate. 

Robinul should be used with caution with potassium chloride because concomitant use can decrease bowel movement and can cause irritation or lesions in the stomach and intestine. 

There are no adequate studies done on Robinul to determine safe and effective use in pregnant women. Small amounts of Robinul pass the placental barrier. 

It is unknown if Robinul enters breast milk. It is best to be cautious before using it in breastfeeding mothers. Anticholinergics may cause suppression of lactation.

Common side effects of glycopyrrolate are:

• dry mouth,
• urinary retention,
• blurred vision,
• dilated pupils,
• increased heart rate,
• sweating,
• weakness,
• dizziness,
• dry skin,
• constipation,
• urinary retention, and
• mental confusion.

Anticholinergics, including Robinul Injection, can produce certain effects, most of which are extensions of their pharmacologic actions. Adverse reactions may include

• xerostomia (dry mouth);
• urinary hesitancy and retention;
• blurred vision and photophobia due to mydriasis (dilation of the pupil);
• cycloplegia;
• increased ocular tension;
• tachycardia;
• palpitation;
• decreased sweating;
• loss of taste;
• headache;
• nervousness;
• drowsiness;
• weakness;
• dizziness;
• insomnia;
•  nausea;
• vomiting;
• impotence;
• suppression of lactation;
• constipation;
•  bloated feeling;
• severe allergic reactions including anaphylactic/anaphylactoid reactions;
• hypersensitivity;
• urticaria, pruritus, dry skin, and other dermal manifestations;
• some degree of mental confusion and/or excitement, especially in elderly persons.

In addition, the following adverse events have been reported from post-marketing experience with Robinul:

• malignant hyperthermia;
• cardiac arrhythmias (including bradycardia, ventricular tachycardia, ventricular fibrillation);
• cardiac arrest;
• hypertension;
• hypotension;
• seizures; and
• respiratory arrest.

Post-marketing reports have included cases of heart block and QTc interval prolongation associated with the combined use of glycopyrrolate and an anticholinesterase. Injection site reactions including

• pruritus,
• edema,
• erythema, and
• pain have also been reported.

Robinul is chemically a quaternary ammonium compound; hence, its passage across lipid membranes, such as the blood-brain barrier is limited in contrast to atropine sulfate and scopolamine hydrobromide. For this reason the occurrence of CNS-related side effects is lower, in comparison to their incidence following administration of anticholinergics which are chemically tertiary amines that can cross this barrier readily.

The concurrent use of Robinul Injection with other anticholinergics or medications with anticholinergic activity, such as phenothiazines, antiparkinson drugs, or tricyclic antidepressants, may intensify the antimuscarinic effects and may result in an increase in anticholinergic side effects.

Concomitant administration of Robinul Injection and potassium chloride in a wax matrix may increase the severity of potassium chloride-induced gastrointestinal lesions as a result of a slower gastrointestinal transit time.