Interacting drugs - summary

Respirdone +  Levodopa

Risperidone may antagonise the effects of levodopa and dopamine agonists

Carbamazepine + Respiridone 

Chronic administration of carbamazepine with risperidone may increase the clearance of risperidone

Clozapine + Rispiridone

Chronic administration of clozapine with risperidone may decrease the clearance of risperidone

Depression

Approved by FDA on December 29,1993.

Usual initial dosage:

Administer on a twice-daily schedule,generally beginning with 1mg twice daily, with increases in increments of 1mg twice daily on the second and third day as tolerated, to a target dose of 3mg twice daily by the third day.

When dosage adjusments are necessary,small dose increments/decrement of 1mg twice daily are recommended.

Overdosage- Symptoms

  Exageration of the drugs pharmacological effects,

Treatment

 1. In case of overdosage, establish and maintain an airway eg drowsiness, sedation, tachycardia, hypotension, and ensure oxygenation and ventilation. extrapyridamal symptoms.

2. Consider gastric lavage and administration of activated One case was aasiciated with a seizure. charcoal together with a laxative.

3. Commence cardiovascular monitoring to detect possible arrhythmias .

4. If antiarrhythmic therapy is administered disopyramide procainamide, and quibidine carry a theoritical hazard of QT- prolonging effects that might be additive to those of resperidone , resulting in problematic hypotension.

5.There is no specific antidote to resperidone, therfore institute appropriate supportive measures.

6.Treat hypotension and circulatory collapse with appropiate measures such as IV fluids or sympathomimetic agents (epinephrine and dopamine should not be used since beta stimulation may worsen hypotension in the setting of risperidone-induced blockade). In cases of severe extrapyridamidal symptoms administer anticholinergic medication

 Missed dose-

 1. If you miss a dose of this medicine, take it as soon as possible.

2. However, if it is almost time for next dose, skip the missed dose and go back to your regular dosing schedule.

3. Do not double doses.

RESPIRIDONE-

1.Advise patients of the risk of orthostatic hypotension,especially during the the period of initial dose titration.

2. Since risperidone has the potential to impair judgement, thinking or motor skills,caution patients about operating hazardous machinery,including automoboliles. Advise patients to avoid alcohol while taking risperidone.

3.Advise patients to notify their physician if they become pregnant or intend to become pregnant during therapy, and not to breast feed if they are taking risperidone

4. Allergies- Tell your doctor if you had any unusual or allergic reactions to respiridone Tell your doctor if you are allergic to any other substances such as foods, or drinks.

5. Pregnancy- Studies with respiridone has not been done in pregnant women. Some unwanted side efects have been reported in animal studies, but the risk with human babies is not clear. Before taking this medicine make sure that your doctor knows that you are pregnant or hoping to become pregnant

. 6. Breast feeding- Respiridone has not been to show to pass into breast milk of nursing animals. It may into human milk and cause unwanted effects such as behaviuor changes in nursing babies. It may be necesary for you to take another medicine or to stop breast feeding during treatment.

7. Children- Studies on this medicine have been done only on adult patients and there is no specific information comparing use of respiridone with use in other age groups

8. Elderly- Are more sensitive to the effects of respiridone. This may increase the chance of side effects during treatment

9. Other medicines- Tell your doctor if you are taking any of the following medicines- Antihypertensives or Central nervous system depressants or Tricyclic antidepressants - respridone may add to the effects of tesemedicines causing unwanted effects.

10. Other medical problems- Tell your doctor if you have any other medical problems- Brain tumor or Drug overdose or Intestinal obstruction or Reyes syndrome - risperidone may mask the signs and symptoms of these condtions

11. Missed dose- If you miss a dose ofvthis medicine take it as sooon as possible. However, if it is almost time for the next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

12. Storage - Keep out of reach of children. Store away from heat or direct sunlight. Do not store the capsule in bathroom, near the kitchen sink, or in other damp places.

13. Outdated medicines - Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of reach of children.

Pharmacology:

Risperidone is an antipsychotic agent belonging to the benzisoxazole derivative class. The mechanism of action is unknown.

Phamacokinetics:

Risperidone is well absorbed. It is extensively metabolised in the liver to a major active metabolite,9-hydroxyrisperidone, which appears proximately equi-effective with risperidone with respect to receptor binding activity. Apparent half-life of risperidone and 9-hydroxyrisperidone was 3 and 21 hours in extensive metabolizers and 20 and 30 hours in poor metabolizers respectively.

Not available.

Pregnancy:

There are no adequate and well controlled studies in pregnant women. Use with caution in pregnancy,only if the potential benefit justifies the potential risk to the fetus.

Lactation:

It is not known whether risperidone is excreted in breast milk. Women receiving risperidone should not breast feed.

Children-

Safety and efficacy in children have not been established.