Leg cramps

Question 1

Quinine

Common indications

Answer 1

1. Quinine is commonly used for the treatment and prevention of night-time leg cramps but should really be resevered for cases when cramps regularly disrupt sleep and when non-pharmacological methods, such as stretching have failured
2. Quinine is a first-line treatment option for plasmodium falciparum malaria

Question 2

Quinine

MOA

Answer 2

• Leg cramps are cuased by painful involuntary contraction of skeletal muscle.
• It is thought to act by reducing excitability of motor end plate in response to ACh stimulation
• This reduces the frequency of muscle contraction
• In malaria- the MOA is not well understood but overall it leads to rapid killing of P.falciparum parasites in the schiznot stage in the blood

Question 3

Quinine

Adverse effects

Answer 3

• Although quinine is usually safe at recommended doses, it is potentially very toxic and can be fatal in overdose
• It causes: tinnitus, deafness and blindness (which may be permanent), GI upset and hypersentivity reactions
• Qunine prolongs the QT interval and may therefore pre-dispose to arrhythmias
• Hypoglycaemia can occur and can be particularly problematic in patients with malaria, which also predisposes to hypoglycaemia

Question 4

Qunine

Warnings

Answer 4

• Quinine should be prescribed with caution in people with existing hearing or visual loss
• It is teratogenic, so should not be prescribed in the first tri-mester of pregnancy, although in the case of malaria it’s benefits outweigh the risk
• Qunine should be avoided in people wiht G6PD deficieny as it can precipitate haemolysis

Question 5

Qunine

Interactions

Answer 5

• Qunine should be prescribed with caution in patients taking other drugs that prolong QT interval or cause arrhythmias such as amiodarone, anti-psychotics, quinolones, macrolide and SSRIs

Question 6

Qunine

Communication

Answer 6

• For nocturnal leg cramps, explain that you are recommending a 4 week trial of quinine in the hope of reducing the frequency of cramps
• If there is no improvement after 4 weeks they are unlikely to experience any benefit and should stop taking it
• Ask your patients to report any adverse effects- such as loss of hearing, visual disturbances and palpitations immediately

Question 7

Qunine

Monitoring

Answer 7

• Review your patients symptoms after 4 weeks and advise them to stop taking quinine if there has not been a significant improvement
• review again at 3 months and consider discontinuation
• Aim to avoid long-term use due to potentially serious side effects

Question 8

Baclofen

Indications

Answer 8

• Pain of muscle spasm in paliative care
• Hiccup due to gastric distension in palliative care
• Chronic severe spasticity resulting from disorders such as multiple sclerosis
  *

Question 9

Baclofen

MOA

Answer 9

• Baclofen is an antispastic agent acting at the spinal level
• GABA derivative
• Acts as a GABAb agonist. This stimulation, in turn, inhibits the release of excitatory amino acids glutamate and aspartate.
• Neuromuscular transmission is unaffected by baclofen

Question 10

Baclofen

Warnings

Answer 10

• Containdicated in active peptic ulceration
• Cautioned in
  
  • Psychiatric disorders- Psychosis, schizophrenia, depression or PD may be exacerbated by baclofen, close monitoring required
  • Epilepsy- Baclofen may also exacerbate epileptic manifestations
  • Cerebrovascular accidents
  • Elderly
  • Urinary disorders- acute retention of urine may occur

Question 11

Baclofen

Adverse effects

Answer 11

• CNS- Sedation, confusion, resp depression, hallucination, euphoria
• Visual impairment
• Hypotension
• Pollakiuria, enuresis, dysuria
• Seizures

Question 12

Baclofen

Interactions

Answer 12

• Antidepressants- TCAs= increased risk of hypotension, sedation and antimuscarinic effects
• Levodopa- Increased risk of confusion, hallucinations, nausea and agitation. Worsening of PD has also occurred
• Antihypertensives- concurrent use is likely to cause a rapid drop in BP