INTRODUCTION Psychopharmacology is the study of drugs used to treat psychiatric disorders. They have significant effect on higher mental functions. They work by adjusting levels of brain chemicals, or neurotransmitters, like dopamine, gamma aminobutyric acid (GABA), norepinephrine, and serotonin. THE CLASSIFICATION OF DRUGS INCLUDES: Antipsychotic agents Antidepressant agents Mood stabilizing agent Anxiolytics and Hypnos sedatives Anti epileptic drugs Anti parkinsonian drugs Miscellaneous
MOOD STABILIZER Any medication that is able to decrease vulnerability to subsequent episodes of mania or depression and not exacerbate the current episode or maintenance phase of treatment. GARY.S – (1996) Commonly used mood stabilizers are Lithium Carbamazepine Sodium valproate
lITHIUM
DESCRIPTION Lithium is used to treat and prevent episodes of mania in people with bipolar disorder (manic-depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods). It works by decreasing abnormal activity in the brain . Lithium therapy remains a key component in the treatment of psychiatric conditions where the main symptoms are mood changes but requires strict monitoring.
HISTORY YEAR NAME DISCOVERED In 1817 Johan August Arfvedson Lithium was discovered as a chemical element In 1847 Garrod Lithium treatment for gout In 1870 Silas weir Lithium bromide as an anticonvulsant and a hypnotic In 1871, William Hammond First recorded use of lithium for mania In 1894 Fredrick Used in the prevention of melancholic depression In 1949 John Cade Rediscovered the use of lithium for mania In 1970 FDA Approved the use of lithium for mania
MECHANISM OF ACTION BRAIN STRUCTURE NEUROTRANSMITTER MODULATIONS INTRACELLULAR CHANGES MULTIPLE LEVELS OF ACTION OF LITHIUM But the exact mechanism of action of lithium is unknown.
PATHOPHYSIOLOGY
PHARMACOKINETICS Half life – 18 – 24hrs Lithium is readily absorbed with peak plasma levels occuring 2 – 4 hours after a single oral dose of lithium carbonate Lithium is distributed rapidly in liver, kidney, muscle, bone and brain. Elimination is predominantly 95% via kidneys and is influenced by sodium balance Depletion of sodium can precipitate lithium toxicity
DOSAGE Lithium is available in the form of following preparation: Lithium carbonate 300mg ( Licab ) 400mg sustained release tablets ( lithosun – SR) Lithium citrate 300mg/5ml liquid
Contd.. The usual range of dose per day in acute mania is 900 – 2100mg given in 2 – 3divided doses. The treatment is started with after serial lithium estimation is done after a loading dose of 600mg or 900mg of lithium to determine the pharmacokinetics.
INDICATIONS ACUTE MANIA PROPHYLAXIS FOR BIPOLAR AND UNIPOLAR MOOD DISORDER SCHIZOAFFECTIVE DISODER BORDERLINE PERSONALITY DISORDER
OTHER INDICATIONS CYCLOTHYMIA IMPULSIVITY AND AGGRESSION TRICHOTILLOMANIA
CONTRA INDICATIONS Cardiovascular disease Concomitant use of diuretics Debilitation Dehydration Renal diseases, sodium depletion Pregnancy
LITHIUM LEVEL..??
LEVELS OF LITHIUM TOXICITY Mild Lithium toxicity – reaches 1.5 mEq /L or higher Moderate toxicity – 2.0 mEq /L and above which is life threatening in rare cases. Levels of 3.0 mEq /L and higher are considered as medical emergency.
ADVERSE EFFECTS L – Leucocytosis I – Insipidus (Diabetic) T – Tremors, teratogenicity H – Hypothyroidism I – Increased weight gain U – Vomiting(GI disturbances) M - Miscellaneous – ECG changes, Acne
SYSTEM NEUROLOGICAL Tremors, motor hyperactivity, muscular weakness, cogwheel rigidity, seizures, neurotoxicity 2. RENAL Polydipsia, polyuria, tubular enlargement, nephritic syndrome 3. CARDIOVASCULAR: T – WAVE depression 4. GATROINTESTINAL Nausea, vomiting, diaarhoea , abdominal pain and metallic taste 5. ENDOCRINE Abnormal thyroid function, goitre , weight gain 7. PREGNANCY & LACTATION Teratogenic possibility Increased incidence of ebstein’s anomaly Secretes in milk and causes toxiity in infant 6. DERMATOLOGICAL Acniform eruptions, populareruptions and exacerbation of psoriasis
Lithium toxicity
MEANING Lithium toxicity is another term for a lithium overdose or poisoning Lithium is similar to sodium. In addition, lithium may inhibit the release of monoamines from nerve endings and increase their uptake. TYPES OF POISONING: ACUTE POISONING –voluntary or accidental ingestion in untreated patient ACUTE ON CHRONIC – Voluntary or accidental ingestion in patient currently using lithium CHRONIC OR THERAPEUTIC – progressive lithium toxicity in a patient on lithium therapy.
SIGNS & SYMPTOMS MILD – MODERATE TOXICITY: Generalized weakness Fine resting tremor Mild confusions MODERATE – SEVERE TOXICITY: Severe tremors Muscle fasciculations Stupor Seizures COMA Signs of cardiovascular collapse
COMPLICATIONS Truncal and gait ataxia Nystagmus Hypertonicity Short term memory deficits Dementia( rare) PROGNOSIS: Most cases of lithium toxicity result in a favourable outcome; however up to 10% of individuals are with severe toxicity.
MANAGEMENT There is no specific antidote for lithium toxicity Vital signs monitoring – unusual signs Lab studies – serum lithium level, electrolytes, RFT and ECG as soon as possible Gastric lavage or bowel irrigation – if have taken lithium within one hour. IV fluids – to restore electrolyte balance Hemodialysis – to remove excess lithium from blood Medication – if seizure occurs
NURSE’S RESPONSIBILITY Baseline evaluation – ECG, LFT, RFT, urine analysis Serum lithium levels should be monitored every 3 – 4 days during initial phase of therapy and every 1 – 2 months, weekly monitoring. Lithium should be monitored at the 12 th hour of last dose. Assess of increased urine output, persistent thirst is important Assess for therapeutic response
PATIENT EDUCATION Lithium should be taken after meals Take as directed Do not discontinue the drug except physician advice. Thirst and frequent urination may occur Oral fluid intake of 2 – 3lit/day and normal intake of salt to avoid dehydration. Educate about side effects and Advice to inform immediately when side effects are notified. Inform about the regular checkup.
TO RECAPITULATE… ANY QUESTIONS??
REFERENCES Abou-Saleh MT, Coppen A. The efficacy of low-dose lithium: clinical, psychological and biological correlates. J Psychiatr Res. 1989;23:157–162. doi : 10.1016/0022-3956(89)90006-X Bschor T. Lithium in the treatment of major depressive disorder. Drugs. 2014;74:855–62 . Erden A, et al. Lithium intoxication and nephrogenic diabetes insipidus : a case report and review of literature. Int J Gen Med. 2013;6:535–9 . Jaeger A, et al. When should dialysis be performed in lithium poisoning? A kinetic study in 14 cases of lithium poisoning. J Toxicol Clin Toxicol . 1993;31(3):429–47.