What stronger pain medication can be given for moderate to severe pain associated with kidney stones or urinary tract infections?

Stronger Pain Medication for Kidney Stones or UTI

For moderate to severe pain from kidney stones or urinary tract infections, you should give NSAIDs (such as diclofenac 50-75 mg IM or ketorolac) as first-line therapy, or morphine 5-10 mg IV/SC if NSAIDs are contraindicated or inadequate. 1

First-Line Approach: NSAIDs

• NSAIDs are equally effective as opioids for renal colic pain but cause significantly fewer adverse effects (vomiting in ~6% vs ~20% with opioids). 1
• Diclofenac 50-75 mg intramuscularly is the most studied and recommended NSAID for acute renal colic pain. 1
• Ketorolac is another effective option, typically given 30 mg IV/IM initially. 1
• NSAIDs should be used for short durations only (typically 3-5 days) with careful monitoring in kidney disease patients. 2

Critical Contraindications to NSAIDs

• Never use NSAIDs in pregnancy, heart failure, renal artery stenosis, dehydration, pre-existing renal impairment, or in very elderly patients. 1
• Avoid in patients on nephrotoxic drugs or with chronic kidney disease stages 4-5 (eGFR <30 mL/min). 3, 2

Second-Line: Strong Opioids

When NSAIDs fail or are contraindicated, escalate to strong opioids:

Morphine (First Choice)

• Morphine 5-10 mg IV or subcutaneous is the opioid of first choice for moderate to severe pain. 3
• Oral morphine 20-40 mg can be used if the patient can tolerate oral route. 3
• The oral to parenteral conversion ratio is 3:1 (divide oral dose by 3 for IV/SC dosing). 3

Alternative Strong Opioids

• Hydromorphone 1-2 mg IV (7.5x more potent than oral morphine) - particularly useful for rapid titration. 3, 2
• Oxycodone 20 mg oral (1.5-2x more potent than oral morphine) if oral route is feasible. 3, 4, 2
• Fentanyl 50-100 mcg IV - shorter onset, useful for breakthrough pain. 5, 2

Special Consideration: Renal Impairment

• If the patient has chronic kidney disease stages 4-5 (eGFR <30 mL/min), fentanyl or buprenorphine are the safest opioid choices due to lack of active metabolite accumulation. 3, 5, 2
• Avoid morphine and hydromorphone in severe renal impairment due to toxic metabolite accumulation. 2

Combination Therapy

• Adding morphine to an NSAID provides additional pain relief in approximately 10% of patients who don't respond adequately to either agent alone. 1
• This combination approach is reasonable when monotherapy with maximum-dose NSAID fails. 1

Weak Opioids (Generally Not Recommended for Severe Pain)

• Tramadol 50-100 mg or codeine 30-60 mg are options for mild-to-moderate pain but have ceiling effects. 3
• Weak opioids should not be used for severe pain - escalate directly to strong opioids instead. 3

Critical Management Points

• Prescribe laxatives routinely with all opioids to prevent constipation. 3
• Prescribe antiemetics (metoclopramide or antidopaminergics) prophylactically with opioids to manage nausea/vomiting. 3
• Use around-the-clock dosing, not "as needed" for ongoing pain control. 3
• Provide breakthrough doses equivalent to 10% of total daily opioid dose for rescue analgesia. 3

Common Pitfalls to Avoid

• Don't use paracetamol/acetaminophen alone for severe renal colic - it has not been adequately studied for this indication. 1
• Don't add antispasmodics (like scopolamine) - they provide no additional benefit when combined with opioids. 1
• Don't delay drainage if obstruction with infection is present - this is a urologic emergency requiring immediate decompression to prevent sepsis and permanent renal damage. 6, 7
• Don't use NSAIDs chronically in kidney disease patients - limit to short courses only. 2