Dicyclomine Capsules

Dosage must be adjusted to individual patient needs.

2.1 Oral Dosage and Administration in Adults

The recommended initial dose is 20 mg four times a day.

After one week treatment with the initial dose, the dose may be increased to 40 mg four times a day unless side effects limit dosage escalation.

If efficacy is not achieved within 2 weeks or side effects require doses below 80 mg per day, the drug should be discontinued. Documented safety data are not available for doses above 80 mg daily for periods longer than 2 weeks.

• Dicyclomine hydrochloride 10 mg capsules: Clear Dark Blue cap/Clear Dark Blue body hard gelatin capsules, imprinted with white ink WATSON over 794 on cap and 10 mg on the body
  
• Dicyclomine hydrochloride 20 mg tablets: Blue, round, unscored, flat-faced, beveled-edge tablets, debossed WATSON and 795 on the periphery on one side and plain on the other side

Dicyclomine hydrochloride is contraindicated in infants less than 6 months of age [see Use in Specific Populations (8.4)], nursing mothers [see Use in Specific Populations (8.3)], and in patients with:

• unstable cardiovascular status in acute hemorrhage
• myasthenia gravis [see Warnings and Precautions (5.4)]
• glaucoma [see Adverse Reactions (6.3) and Drug Interactions (7.1)]
• obstructive uropathy [see Warnings and Precautions (5.8)]
• obstructive disease of the gastrointestinal tract [see Warnings and Precautions (5.5)]
• severe ulcerative colitis [see Warnings and Precautions (5.7)]
• reflux esophagitis

The pattern of adverse effects seen with dicylomine is mostly related to its pharmacological actions at muscarinic receptors [see Clinical Pharmacology (12)]. They are a consequence of the inhibitory effect on muscarinic receptors within the autonomic nervous system. These effects are dose-related and are usually reversible when treatment is discontinued.

The most serious adverse reactions reported with dicyclomine hydrochloride include cardiovascular and central nervous system symptoms [see Warnings and Precautions (5.2, 5.3)].

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The data described below reflect exposure in controlled clinical trials involving over 100 patients treated for functional bowel/irritable bowel syndrome with dicyclomine hydrochloride at initial doses of 160 mg daily (40 mg four times a day)

In these trials most of the side effects were typically anticholinergic in nature and were reported by 61% of the patients. Table 1 presents adverse reactions (MedDRA 13.0 preferred terms) by decreasing order of frequency in a side-by-side comparison with placebo.

Nine percent (9%) of patients were discontinued from dicyclomine hydrochloride because of one or more of these side effects (compared with 2% in the placebo group). In 41% of the patients with side effects, side effects disappeared or were tolerated at the 160 mg daily dose without reduction. A dose reduction from 160 mg daily to an average daily dose of 90 mg was required in 46% of the patients with side effects who then continued to experience a favorable clinical response; their side effects either disappeared or were tolerated.

6.2 Postmarketing Experience

The following adverse reactions, presented by system organ class in alphabetical order, have been identified during post approval use of dicyclomine hydrochloride. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

• Cardiac disorders: palpitations, tachyarrhythmias
  
• Eye disorders: cycloplegia, mydriasis, vision blurred
  
• Gastrointestinal disorders: abdominal distension, abdominal pain, constipation, dry mouth, dyspepsia, nausea, vomiting
  
• General disorders and administration site conditions: fatigue, malaise
  
• Immune System Disorders: drug hypersensitivity including face oedema, angioedema, anaphylactic shock
  
• Nervous system disorders: dizziness, headache, hallucinations insomnia, somnolence, syncope
  
• Psychiatric disorders: As with the other anti-cholinergic drugs, cases of delirium or symptoms of delirium such as amnesia (or transient global amnesia), agitation, confusional state, delusion, disorientation, hallucination (including visual hallucination) as well as mania, mood altered and pseudodementia, have been reported with the use of Dicyclomine. Nervousness and insomnia have also been reported.
  
• Reproductive system and breast disorders: suppressed lactation
  
• Respiratory, thoracic and mediastinal disorders: dyspnoea, nasal congestion
  
• Skin and subcutaneous tissue disorder: dermatitis allergic, erythema, rash

6.3 Adverse Reactions Reported with Similar Drugs with Anticholinergic/Antispasmodic Action

Gastrointestinal: anorexia,

Central Nervous System: tingling, numbness, dyskinesia, speech disturbance, insomnia

Peripheral Nervous System: With overdosage, a curare-like action may occur (i.e., neuromuscular blockade leading to muscular weakness and possible paralysis).

Ophthalmologic: diplopia, increased ocular tension

Dermatologic/Allergic: urticaria, itching, and other dermal manifestations;

Genitourinary: urinary hesitancy, urinary retention in patients with prostatic hypertrophy

Cardiovascular: hypertension

Respiratory: apnea

Other: decreased sweating,sneezing, throat congestion, impotence. With the injectable form, there may be temporary sensation of light-headedness. Some local irritation and focal coagulation necrosis may occur following the intramuscular injection of dicyclomine hydrochloride.

7.1 Antiglaucoma Agents

Anticholinergics antagonize the effects of antiglaucoma agents. Anticholinergic drugs in the presence of increased intraocular pressure may be hazardous when taken concurrently with agents such as corticosteroids. Use of dicyclomine hydrochloride in patients with glaucoma is not recommended [see Contraindications (4)].

7.2 Other Drugs with Anticholinergic Activity

The following agents may increase certain actions or side effects of anticholinergic drugs including dicyclomine hydrochloride: amantadine, antiarrhythmic agents of Class I (e.g., quinidine), antihistamines, antipsychotic agents (e.g., phenothiazines), benzodiazepines, MAO inhibitors, narcotic analgesics (e.g., meperidine), nitrates and nitrites, sympathomimetic agents, tricyclic antidepressants, and other drugs having anticholinergic activity.

7.3 Other Gastrointestinal Motility Drugs

Interaction with other gastrointestinal motility drugs may antagonize the effects of drugs that alter gastrointestinal motility, such as metoclopramide.

7.4 Effect of Antacids

Because antacids may interfere with the absorption of anticholinergic agents including dicyclomine hydrochloride, simultaneous use of these drugs should be avoided.

7.5 Effect on Absorption of Other Drugs

Anticholinergic agents may affect gastrointestinal absorption of various drugs by affecting on gastrointestinal motility, such as slowly dissolving dosage forms of digoxin; increased serum digoxin concentration may result.

7.6 Effect on Gastric Acid Secretion

The inhibiting effects of anticholinergic drugs on gastric hydrochloric acid secretion are antagonized by agents used to treat achlorhydria and those used to test gastric secretion.

12.1 Mechanism of Action

Dicyclomine relieves smooth muscle spasm of the gastrointestinal tract. Animal studies indicate that this action is achieved via a dual mechanism:

• a specific anticholinergic effect (antimuscarinic) at the acetylcholine-receptor sites with approximately 1/8 the milligram potency of atropine (in vitro, guinea pig ileum); and
• a direct effect upon smooth muscle (musculotropic) as evidenced by dicyclomine’s antagonism of bradykinin- and histamine-induced spasms of the isolated guinea pig ileum.

Atropine did not affect responses to these two agonists. In vivo studies in cats and dogs showed dicyclomine to be equally potent against acetylcholine (ACh)- or barium chloride (BaCl2)-induced intestinal spasm while atropine was at least 200 times more potent against effects of ACh than BaCl2. Tests for mydriatic effects in mice showed that dicyclomine was approximately 1/500 as potent as atropine; antisialagogue tests in rabbits showed dicyclomine to be 1/300 as potent as atropine.

12.2 Pharmacodynamics

Dicyclomine hydrochloride can inhibit the secretion of saliva and sweat, decrease gastrointestinal secretions and motility, cause drowsiness, dilate the pupils, increase heart rate, and depress motor function

12.3 Pharmacokinetics

Absorption and Distribution
In man, dicyclomine is rapidly absorbed after oral administration, reaching peak values within 60-90 minutes. Mean volume of distribution for a 20 mg oral dose is approximately 3.65 L/kg suggesting extensive distribution in tissues.

Elimination The metabolism of dicyclomine was not studied The principal route of excretion is via the urine (79.5% of the dose). Excretion also occurs in the feces, but to a lesser extent (8.4%). Mean half-life of plasma elimination in one study was determined to be approximately 1.8 hours when plasma concentrations were measured for 9 hours after a single dose. In subsequent studies, plasma concentrations were followed for up to 24 hours after a single dose, showing a secondary phase of elimination with a somewhat longer half-life. 

In controlled clinical trials involving over 100 patients who received drug, 82% of patients treated for functional bowel/irritable bowel syndrome with dicyclomine hydrochloride at initial doses of 160 mg daily (40 mg four times daily) demonstrated a favorable clinical response compared with 55% treated with placebo (p<0.05).

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